Information On Tortoise Body

 

One Of The Most Popular Questions That We Get Asked Is- Is It A Turtle?

   No, although tortoise can sometimes be known as a Land Turtle, and the Americans like to class everything as a turtle, particularly thanks to the Teenage Mutant Ninja Turtle phenomenon. However, ours are a breed of tortoise called the Giant Aldabra Tortoise. The basic UK rule is that tortoises live on the land and turtles live in the sea, whilst terrapins span a bit of both but stick with freshwater rather than sea water.

 

   Tortoises also tend to be more domed shaped, in the shell, and turtles are flatter, and smoother, to make them more streamlined in the water. Both tortoises and turtles come in many different patterns and colours, depending on what they need to hide from and how hot their original environment is.

 

   In some, millions of way, way, way, distant past there would probably have been a common ancestor but now turtles rarely come on land and tortoises rarely enter the water.

 

How Much Do They Eat?

   It is difficult to say exactly how much an Aldabra tortoise eats in a day because they are a grazing animal. When they are let out of their house, in a morning, they go off foraging, helping themselves to as much as they want. At a rough guesstimate Samson, our biggest tortoise, can probably munch his way through 4 or 5 carrier bags of grass and weeds, on a nice day. In spring when the grass is fresh and new they will eat more. He does spend several hours just eating!

 

   One common mistake owners, and keepers, make is to dump a pile of food conveniently in front of them and then refill and refill, with the idea that its a big tortoise it must have a big appetite and want to eat all day. The problem with that is that the tortoise is gaining weight but not getting any exercise. If you sat in a chair and ate five, full portion, meals a day for a month, you would put on weight too but with not moving around you would not be converting that food into muscle mass, which is what they need to haul their heavy bodies around.

 

   Grass is not the most nutritious of foods, but that is the type of sustenance that their body is set up for. Aldabra is a harsh place but their nutritional requirements have evolved over many millennia, we cannot think that we know best when we don’t. Everyone want to treat their animal once in a while, and that is fine, but they don’t need to be fed 12 cauliflowers in a day- ‘think have a chocolate - not a box full!’ Continually eating anything too high protein will set the animal up for body issues and anything too sweet will cause digestive issues- you don’t want diarrhoea in an animal the size of Samson!.

 

   In captivity tortoises need extra calcium, vitamins and UVB light to avoid metabolic bone disease, which causes softening and malformation of bones and shell. It is caused by incorrect husbandry.

 

   Diet and lifestyle changes may improve the condition slightly, in the future but it is a very slow process and although it may become less noticeable as the animal grows, it is generally permanent. Pyramiding is quite common in captive tortoises and is caused by a diet of excess protein, inadequate calcium and low fibre as well as other dietary excesses or deficiencies. A high protein diet will lead to liver problems, which are incurable.

 

   On Aldabra, the temperature is often too hot for them to do much other than hide from the sun for a lot of the day, so an Aldabra tortoise can spend up to 18 hours a day just sleeping. This means that when they are awake they need to be moving around and eating, leave them to make up their own mind how much they want to feed on but make them work for it, it stimulates their mind as well as body.

 

   The tropical rain on Aldabra can change the landscape within just a few hours, the tortoises have been waiting for this to arrive and refresh the foliage so it will grow once more. As a result they will eagerly eat their fill, after potentially months of meagre rations and fasting, hence them being able to sit and happily eat for several hours constantly. Aldabra's in the wild consume 26 million lbs or 11.8 million kg of plant matter each year.

 

 

Do They Chew Their Food?

   No, they do not have molar teeth to grind their food down. They only have a beak at the front and a finely serrated jaw line, so when they take a bite whatever they have in their mouth gets swallowed down whole. It must be quite uncomfortable- imagine yourself taking a bite of an apple and swallowing it straight down without chewing first!

 

Do They Have Teeth?

   No, instead they have a beak at the front of their mouth to pierce their food and hold it in place as a serrated jaw line cuts through the food but they also have a strong bite. They can eat through foods like pumpkin and watermelon, which have very tough outer skins, and crunch through a carrot in one bite. If you get your finger in the way when they are eating, they will accidentally give you a nasty nip, which can go down to the bone and maybe through it if the animal were big enough. This is why we do not allow hand feeding of our animals by the public.

 

   In general, a healthy tortoise beak is slightly longer on the top and curved ever so slightly downward over the bottom. However, depending on their diet they can grow faster than the animal can naturally wear it down and in cases like these the vet has to intervene and file the beak down for them.

 

   An overgrown or deformed beak can directly impact the animals ability to eat. The beak should not be crooked and should never be held open for extended periods. The feeding of hard foods like pieces of carrot or tough to shred foods like hay are a good natural method of helping to keep the beak growth under control.

 

   Many tortoises don’t like being poked and prodded, and a healthy tortoise will determinedly resist you from opening its mouth. A normal tortoise mouth should be pink and clear inside.

Treat time- they only get watermelon and apples as a special treat

Why Do They Eat Poo?

   Many tortoises routinely eat their own, and other animals, droppings this is probably to extract more nutrients, by digesting it again, or to get to the healthy microbes in it if they have an imbalance in their own gut bacteria.

 

Do They Drink A Lot?

   Despite being surrounded by miles and miles of in the form if the Indian Ocean, there is very limited freshwater on their island that they can actually drink. This collects in pools after the rain, being near the equator monsoon season is between November and March. So for several months of the year the tortoises are unable to drink and are forced to obtain most of their moisture from their food. A quarter of their weight is also taken up by stored fluids in their body for such occasions.

 

   Aldabra tortoises have actually evolved the ability to drink through their noses, as a direct result of there being such a water shortage. They have to make the most of access to every vital drop. They have very elaborate nasal passages, which form a deeply ascending loop before entering the throat. It also has a large fleshy flap, made of tissue, near the opening to the olfactory recess, directing forwards. Its purpose is to block the entrance to its lungs, to stop water from going down there, when it drinks through its nose.

 

   The 19^th Century sailing ships would store a number of them in the hold of the ship and when the crews ran out of water they would drink the urine and fluids stored in the water pouches around the base of the tortoises neck as emergency rations.

 

   One of the dangers in captivity, where we tend to have water available to tortoises at all times, is that they can gorge on it making themselves ill. Too much water available can cause water retention, they get into the mindset that they must drink it all up before the dry season arrives but it never does because we keep refilling the bowl for them!

 

   Like too much food, too much water is bad for them - they were designed to fast through the dry season which lasts for several months. That does not mean that they should be denied all water. Just don't give them a big bowl of water. Also move it around their pen- make them look for it as a form of enrichment.

 

   When our big tortoise Samson, has a drink he swallows once approximately every 9 seconds and can spend several minutes drinking, so he takes on a lot of water at one sitting.

 

   Aldabra tortoises don't sweat so there needs to be plenty of shade available for them during hot times of year. Shade is just as important to reptiles, to help them thermoregulate. Normally they would like to find a mud wallow, to hide in, to cool themselves down. If you leave a hose pipe accidentally running then they will create their own mud wallow and make a real mess of your garden in the process.

 

   Tortoises like to got to the toilet in water, they find it comforting to know that there is fresh water available to take onboard. Naturally it encourages them to go, as they know they wont end up getting dehydrated, once they have passed their used fluids from their systems.

 

The Digestive System

   Tortoises have the same digestive organs as most other vertebrates, however they have adapted to cope with conditions where food and water conservation is necessary, as replenishment is scarce at certain times of the year.

 

   They have the ability to extract and assimilate moisture and nutrients from foods, which we would say were dried up and would be of no nutritional use.

 

   Tortoises achieve this by a means known as a "hindgut system" which is a bit like having two digestive tracts. The second reabsorbs any moisture from waste products already produced by the first so nothing is wasted.

 

   Arid dessert tortoises such as the Sulcata can also split up their urinary waste in their kidneys, allowing them to store valuable water in their bladder and only expelling the waste product in the form of white insoluble uric acid crystals. This has been described as having a similar look to toothpaste or cottage cheese when passed.

 

   Aldabras do drink a lot, at times, but they also pass a lot of urine and copious amounts of poo but it is good for the roses!.

 

Lets Talk About Poo

   Tortoise poo is not something that you need to be scared of. Mention the word poo and most people recoil and go ‘eewww!!’ in disgust. However, most tortoises are Herbivorous, meaning they eat plants ad grass. What comes out the other end is in a neat package of varying size, for ease of passing. It is usually a dark brown or blackish colour and fairly dry. It is a neat bundle of roughage that is not much different to what you would encounter when you clean the lawnmower out.

 

   In spring it can be a lot looser and greener looking, as they are feasting on an abundance of new fresh grass, which has not been dried out by the sun and so contains more fluids. This in turn makes the resulting poo wetter and slimier. It is the fluids that can cause it to smell not the fibrous content. This type of poo also has a strong staining factor, so don’t get it on your best clothes!

 

   Tortoises have a variable gut passage time depending on the species of tortoise.  The average digestion ranges from a few days to 3 weeks, allowing for potential dispersal distances of hundreds of metres. Some seeds can take up to 3 months to pass through an Aldabra gut though.

 

   Not many people have the desire or reason to actually handle tortoise poo but as a species there is a chance of Zoonotic infections like Salmonella, which will make you sick, so it is always advisable to use a good hygiene routine, after touching a tortoise, especially before eating your sandwiches!!

 

Studies have shown that Aldabra poo contains:-

42% Bacteroidetes, which are gut bacteria. 

32% Firmicutes Bacteria which helps maintain metabolic and immune health. It is this that helps break down the fibre that the tortoise has eaten by fermentation, which produces important vitamins amongst other things.

9% Spirochaetes Bacteria which are found in water, mud and sediments. They can cause disease in humans such as Dysentery and Lyme Disease. It is these bacteria why it is important for you to wash your hands

 

   Not all tortoise species pass urates- that's the white stuff -and it should be white or just off white, maybe a hint of grey or yellow. Any other colour or if there is blood in it is a cause for concern. However, if your tortoise is passing gritty or dry urates, this is a problem, it is a sign it is dehydrated, it should be the consistancy of toothpaste or cottage cheese. If you notice your tort straining to pass urine, urates, or faeces, this is something your vet needs to know about.

 

   This little guy did not produce this, one of our larger Aldabra juvenilles did. If this was from Samson there would probably be three times more!

 

   A healthy Sulcata's poo is very similar looking and it would probably produce this much, each time, for a 15 year old animal.

 

 

Do They Have Ears?

   Tortoises have no external ears, they are beneath flaps or smooth scales, usually circular shaped and a darker grey, which are located behind the tortoises eyes, towards the rear of the head. Their hearing is quite good.

 

 

Do They Have A Good Sense Of Smell?

   Yes, tortoises' primary sense is smell and not sight. They can detect smells that human noses cannot, in particular the smell of females. They will sniff at anything new that comes across their path. Our big female Bonnie can sniff out a Banana, even if you have hidden it from view. Besides finding food their sense of smell can help them decide if a spot is good for digging a nest.

 

   Their nostrils are called ‘Nares’ and they breathe through them, but they also scent through them. They smell by pumping their throat to move air past their Jacobsen’s Organ- the scent organ most reptiles use.

 

   A tortoises nose should always be clear. A runny nose is cause for concern. A tortoise who is gasping or has bubbly or thick discharge coming from its mouth or nose may be very ill. It needs to see a vet as soon as possible.

 

   Tortoises’ rib cages don’t move, as this is their hard shell, so they force air in and out of lungs by working front limbs, which can look like they are shrugging their shoulders.

  

Do They Have Good Eyesight?

   Aldabra tortoises have good all-round vision due to having their eyes on the side of their head as opposed to having binocular vision like humans do. It is thought that they use their eyes to catch movement but may have difficulty picking out detail. As they are neither predators nor prey (apart from to humans) they do not need particularly strong eyesight. They eat grasses which are on the floor, or at head height, and close to them so they do not need long sight to find food.

 

   Tortoises are particularly attracted to reds though and other strong colours, food such as strawberries and tomatoes make good rewards, when trying to train them but many owners say that their tortoise will chase them around the garden when they have red toe polish on!

 

  A tortoise should have bright and shiny, alert eyes. Dryness of the eyes could indicate that they are dehydrated or be the onset of an illness. Again, excessively wet, runny, weepy eyes could be a sign of infection too, so don’t ignore discharge and take your animal to a vet if you are concerned.

 

   Aldabra tortoises do often have weeping eyes, it does not mean they are upset or there is anything particularly wrong with them. There are two current thoughts for the reason that this happens. One is that they are like elephants, who produce musk which runs down their faces. The other is that it is a way of them cooling down because they are unable to sweat. If it happens with your Aldabra tortoise, don’t panic it is perfectly normal.

 

   Injuries to the eyes can cause blindness, so peer visually at your tortoises retinas, for scratches, during your regular maintenance checks. However, unless you know what you’re doing, never try to pry a tortoise’s eyelids open.

 

   To protect their eyes while burrowing, tortoises have a third eyelid. Don’t be surprised if you can see your tortoises third eyelid at the front corners of their eyes. However, don’t be alarmed either if you don’t see this eyelid at all, as that is normal too. Sulcata, especially, often have their eyelid closed and it creates a white barrier, making you think they have got cataracts, or something. However it is just a way of keeping the eye protected from dust and heat and they can still see movement through it, to react if there is a predator coming near. If you see that the eyelid is always closed or looks swollen or unusual it could mean an eye injury, or the animal isn’t feeling well in general and needs to be checked by an expert.

 

    Our Aldabras are part of an on going eye study with the Vets from The University of Cambridge.

 

Can They Sense The Weather?

  Yes, tortoises have an inbuilt 'sensor' in their skull, which allows them to evaluate the weather. They know if it is not going to be a good day and it is more efficient for them to stay in bed and have a 'duvet day' or if it is going to be good weather and they should get up early and make the most of it. 

 

  They can also tell when there is going to be bad weather, if it is going to rain hard then they will often head back to bed early. For example, the other day Samson was out in his pen and it was lovely sunny weather, he then made the decision to head back to bed. He went straight there, with no deviation or stopping on the way for a snack, which was unusual. However, he clearly knew something that we did not because half an hour later we had a thunder storm, complete with lightening and stair rod rain but Samson was tucked up warm and in the dry of his house. This sense may be something that develops with age because several of his younger brethren got very wet!

 

Why Do They Have A Long Neck?

   The long neck and ability to raise themselves higher off the ground allows them to reach low hanging browse from trees and shrubs, thus increasing the variety of their diet. Some sub species of Giant Galapagos Tortoises have developed their shells differently to make this easier to achieve. Instead of the usual dome shaped shell they have raised shell above their neck making them look more 'saddle' shaped to allow greater movement of the head.

 

   Most tortoises have 5 vertebra and they fold back in a 'S' shape. However Aldabra have longer necks so they have 8 Vertebra to support the extra length. When they retract their heads into their shells, it is by a vertical 'Z' fold rather than the S shape. Generally when they are super relaxed, they sleep with their head and neck right out, at full extension, either resting on the floor or the shell of a smaller animal.

 

   Some Aldabra's have developed the skill that they can stand on their hind legs and reach out, even higher, for succulent leaves and shoots that are more than 3 feet above ground level. It is an impressive sight to behold. This is a perilous acrobatic feat, for them, as they risk death if they tip over onto their back because they are unable to right themselves and will asphyxiate with the weight of their insides crushing down on their lungs.

 

   Aldabra Tortoises have a shorter, thicker and less mobile necks than their Galápagos counterparts. The saddleback Galapagos Tortoises in particular have a long reach with their neck, so that they can stretch up for browse and gain access to more food resources. They also use they necks for display and fighting other males at breeding time, which is not something the Aldabra tortoise does.

 

Do Tortoises Have Claws?

   Yes, there are five on the front and four on the back feet. A tortoise walks on its toes like an elephant and this is called digitigrade. Tortoises have big claws which allows them to be amazing diggers and climbers, they also allow them to grip in order to clamber over rough terrain.

 

   Tortoises need areas of hard substrate in their enclosures, where they frequently walk, in order to wear their claws down naturally. If they do become overgrown then the smaller breeds can be trimmed using dog nail clippers, but with the large species it requires power tools!

 

Clipping tortoises nails is not something that should be done by an inexperienced person, as it is easy to cut too much off and nick one of the blood vessels, causing a bleed. If you are going to clip nails it is advisable to have paper towels and a silver nitrate pen handy to quench any blood before you begin. Cutting less off and more frequently is always the better option than cutting too much in one go.

 

An adult Hermann has the same number of claws, just a lot smaller!

 

Why Do Tortoises Have Scales?

   A tortoise’s skin is usually quite smooth and dry-feeling, except at the joints where it wrinkles to allow movement, however, if your tortoise is dehydrated then the skin will feel more wrinkled and loose.

 

   Although they are reptiles, the skin has a type of Pachyderm feel, like elephants and rhinos, which means it is quiet thick and leathery to the touch. The skin around the neck, hips and shoulders is a lot smoother because they have to be able to tuck these aspects deeper into their shell and they want to feel comfortable. There is also the fact that arms and feet will pull into place to cover these vulnerable points, so there does not need to be strong protection there.

 

   This smoother skin is is not robust enough to stand up against the harsh environments tortoises live in. There are a lot of rocks and jagged coral to walk and climb over, not to mention the prickly plants tugging at their skin as they pass by. So they have evolved scales on their head and legs, both as a method of protection against injury from whatever source but also as a way of regulating their temperature. The scales also offer much more protection against harsh sun and sandstorms, which could flail thinner skin from their frames.

 

   The colour of these scales are usually shades of browns and greys, the colour variations are called morphs. Colour depends on the species of tortoise, the smaller ones will be looking to blend into their habitat for maximum camouflage against predators, and whereabouts in the world they originate from. Generally the lighter the colour of the tortoise the warmer their country of origin as, it helps to reflect the suns rays away from them, whilst darker skin absorbs the heat better.

 

   The size of the scales will differ to the environment the tortoise naturally calls home. smaller tortoises tuck close inside their shell at the threat of danger so only the outer edges of their limbs have pronounced scales. Aldabra tortoises are not combative animals so they do not need defence protection and they have no real predators. However, they have thick protection on their forearms and feet for when they are walking over and through sharp and hostile terrain, to prevent their skin being sliced open. Where as Sulcata have much more armoured scales, they are formidable to look at, because they are a confrontational species and need to protect themselves as much as possible from attack.

 

   As reptiles, tortoises can shed their skin. However, they are not like a snake and will shed their whole skin in one go- you are not going to go in the pen one day and find a perfect skin replica of a tortoise sat there. Instead they flake off in small bits, its like when your sunburn is peeling off, you will usually notice it on the back of their neck or in their shoulder cavity. Don’t be alarmed by this, it is natural and no different to our skin peeling off to reveal new growth underneath. However, please don’t try to peel the shed skin off the tortoise, it will happen naturally, when ready. If you try to pull it off, you could cause a painful injury that could lead to an infection. If you want to help pop them in a warm bath for a short while and let them soak, it softens the skin as it rehydrates and makes it easier to shed.

 

   A healthy tortoise will not have sores or open wounds anywhere on its skin. If it does then you need to keep a close eye on them to prevent fly strike, which is when flies lay their eggs on an open wound and you can find it covered in maggots. It is a revolting thing and you need to seek veterinary advice if it does happen.

 

   There may be marks and scars from older injuries on their bodies, which should be noted in case it becomes a recurring problem. If it keeps getting a cut from clambering over a certain rock,-remove the rock from its environment, there is no need for unnecessary injuries.

 

   Make sure you also check you tortoise for ticks, mites, and other parasites. They will usually be found close to the shell where the skin is softest or between their thicker scales. If you do find a tick on them do not try to remove it, you may end up leaving the mouth part attached which will cause more problems than if it is allowed to do its thing and fall off naturally. If the tortoise has more than a couple of them then it would be a good idea to seek professional medical advice to remove them, after all they are draining its blood! They are usually found in the long grass and as the tortoise brushes past they latch on, so some attention to their pen may be required to stop them from being re infested. In our experience they are not a common problem, we’ve only had one case in all the time we have kept tortoises.

 

How Does The Shell Help With Seed Dispersal

  Very few tortoise shells grow perfectly smooth, there is always ridges and bumps, in which small seeds or bits of foliage and detritus can get stuck. They will remain perched on the tortoises shell until they get brushed or blown off and then they can begin to grow in a new location, thus spreading the plants range of habitation.

 

  Sometimes, the seeds will begin to grow whilst sat on the back of the tortoise and they can end up wandering around carrying small plants and shrubs. They look a little like an Army Infantryman with camouflage stuck in his Kevlar helmet.. Obviously the larger the foliage is the more chance of it being brushed off by overhanging foliage as they make their way through the undergrowth. So they never really have issues with something growing on them, it has usually been dislodged before it can become a medical problem to their shell.

 

Even in captivity, in this country, seeds get stuck in the ridges and then get blown off else where in the pen.

 

 

What Is The Shell Made Of?

   Keratin and this is the same material that makes you own finger nails, or things like horses’ hooves and Rhino horn but it does not have any medicinal qualities like some cultures believe, it is made up of the same stuff as your hair.

 

How Many Segments Do Tortoise Shells Have?

   The segments , which act like shields, that make up the tortoises shell are called Scutes and the patterns and design differ between species of tortoises, also there are often individual differences among members of the same species. Very old tortoises, particularly wild animals, often have very worn scutes giving their shells a completely smooth appearance. One of the differences between tortoises and Turtles is that Tortoises cannot shed their Scutes, they just get bigger with age.

 

   The Carapace is the top domed section of the shell and here the tortoise has 38 Scutes. The Carapace incorporates tiny pores, which trap in the radiant heat. Oils should never be put on pet tortoise's shells as it significantly hinders their thermoregulation capacities. this means that if you put oil on your tortoise and let them out into the sunshine you effectively run the risk of unintentionally cooking you beloved pet. Give them a nice hose down with some water, they will appreciate it much more.

 

   The Plastron, which is the area beneath the tortoise, has between 12-14 Scutes. Females are flat but males have a concave (internal bowed) Plastron to help in mating, when he climbs on the back of his partner. If his shell were flat he would not be able to balance as well and would probably roll over backwards as a result, risking death as he would not be able to right himself. The anal scutes on female tortoises are usually shorter and more flexible, allowing her to lay her eggs with ease. The Carapace and Plastron are fused together at the sides by a 'Bridge'.

 

   The shell is made of fused bones; the Carapace is a fusion of about 50 bones, including the back ribs and vertebrae. The Plastron, which is underneath the tortoise and protects the tummy, is a union of bones including the clavicle (collar bone) and bones between the clavicle and portions of the front ribs. The names and numbers of these Keratin covered Scutes roughly correspond to the adjacent bones and body portions. The Scutes do not precisely overlap the bones; instead they are staggered, which helps to give more rigidity and strength to the shell.

 

   No matter the species of tortoise, as the shell grows the number of Scutes does not change - just their size as the animal grows and additional rings are added around the base of each one. In between each Scute is a suture line, but is more commonly known as a growth ring. The tortoises can produce several of these regularly, if they are receiving a good diet, you will see them as white lines on an Aldabra and darker rings on some other species of tortoises. This is where the scutes sit against each other and seal the shell closed. Any gaps or soft spots between the scutes are reasons for concern.

 

    The rest of the shell should be hard to offer maximum protection. A healthy shell should be smooth and well sealed. if your tortoises shell is damaged or scarred there could be internal damage too. this is usually from trauma such as dog or fox bites, falling over into a rock or other hard surface or fighting with another tortoise.

Why Are Tortoises Different Colours

   There is no standard colouring for a tortoise’s carapace, the patterns are often down to how much camouflage they need, you will usually find smaller animal breed are more camouflaged in order to hide from predators. As a general rule the colour of the tortoise denotes the area of the world that the tortoise originated from, the lighter the shell covering the hotter the region. This is to repel the heat, those needing more heat, to warm their cold blood. will be a darker colour. The shapes of the shell are also influenced by their natural habitat.

 

   The plastron, beneath the tortoise is usually much paler, often white or yellow but in the Aldabras case it is a dark grey to black colour.

 

   You can notice that your tortoises shell changes colour over time, they may start out a dark colour and gradually lighten that means that their current environment includes lots of UV, which is good for them.

 

   Reptiles have two cells that help to dictate the shell’s colour; the Chromatophores and the Melanocytes. These cells are strategically located to send colour pigments to the shell to give it its colour The tortoise’s colour depends on these cells’ presence and distribution. They cannot change the colour of their basic pigmentation once the embryo fully develops. If you do notice any colour changing in patches or the shell seems different, this indicates an unhealthy shell and could be down to poor nutrion, trauma or infection.

 

Can They Feel Through Their Shell?

   Yes, shells have a blood and nerve supply to them, so bleeding and pain can result if the shell is injured. They can feel you touching them, realistically giving them a stroke on their shell is like a summer breeze blowing lightly on us, we know it is there but it is not really bothering you.

 

   They also get itches on their shell and will rub against something to relieve the irritation- like a bear having a good back scratch!

 

   It used to be popular to drill a tether hole in the back of a tortoises shell shell, by their tail, or rear legs, so that the animal could be attached to a string or chain and not wander off and get lost. When it was done it was probably like having your ears pierced- it hurt at the time but as the body adjusted to it and healed it, so it would no longer hurt. It is no longer considered good practice to do this to a tortoise.

 

Can A Tortoise Come Out Of It's Shell?

   The shell is part of the body of the tortoise and one cannot be removed from the other without killing the animal and please do not try it. It would be like someone skinning you alive and cause immense pain.

 

 Tortoises are not like crabs who shed their shells for a new one when they outgrow the original one. And neither are they like turtles who can shed scutes,  to get rid of parasites that have stuck to it making it less streamlined in the water.  A tortoise keeps its shell for life and it grows with it.

 

How Hard Is a Tortoise Shell?

   Tortoises use their shells for protection against predators; therefore, the harder the shell the better the protection. An adult tortoises shell is very solid, the more they grow the harder the shell becomes and it can take a pressure of up to 200 times its weight without breaking. Surprisingly, an empty tortoise’s shell is even tougher than a live one.

 

   As hatchlings they are born with soft shells to enable them to squeeze inside the egg, where they are bent over in order to fit. Once they hatch, their shell begins to straighten out and harden. At no time in later life should they have a soft shell.

 

   Although the armour, consisting of their hard Scutes is exceptionally strong, there are some predators can still damage and kill a tortoise. Birds will take young animals high into the air and then drop them down onto rocks to crack their shells and gain access to the meat inside. With larger animals a crocodile or a honey badger can break it, though it is not easy and they would only pick on a tortoise if there are no easier alternatives. 

 

   Interestingly, Aldabra tortoises are unique among living giant tortoises because they do have relatively thick shells. Most tortoises trade the thickness of the shell to  make their body weight lighter. However, the shell of a large Aldabra tortoise averages about 7.6 cm (3 inches) thick.

 

   Distressingly many tortoises in the wild are damaged and killed by bullets, as men use them for target practice. The great speed of the bullet exerts a lot of pressure on the surface, tearing through the shells keratin layer. In these situations the tortoise is likely to bleed out. After all someone who has just used the animal for target practice is not really going to regret their actions and rush the injured tortoise to the vets in a fit of contrition are they?

 

   It is said that an adults shell will remain intact, protecting the tortoise within even if you run a small car over it, as a small car exerts little pressure. PLEASE DO NOT TRY THIS AT HOME!!

 

   If your tortoise has a broken or damaged shell, it is not immediately fatal but you need to stop infection from getting in because it is that which will likely kill the tortoise and not the damage itself.

 

   Shell damage can be caused by many things, trauma or poor diet. Unsanitary conditions in their housing can cause ulcers on or around the shell which is known as Shell Rot and this is a condition that can be fatal. It can also lead to kidney damage, liver disease and thyroid issues.

 

   Lack of calcium and not enough sunlight or UVB as well as disease can cause shell abnormalities and weakness. Tortoises cannot moult or grown another shell if their original one is damaged, instead the shell grows with the tortoise. If there is damage to the shell caused by injury and the animal recovers. This healed wound will never truly go away, it may become less visible as the tortoise grows bigger but it will always leave a scar, just like if you cut yourself or have an operation.

 

   There has been some groundbreaking work done by vets over recent years regarding shell damage. Previously if an animals health issue was serious then they would have to be put down. However, now it is becoming more common for vets to replicate damaged portions of shell using fibreglass products. These are then used to keep out infection either whilst a wound heals or as a long term replacement.

 

 

 

 

 

Why Does My Aldabra Have A Split 5^th Vertebral Scute?

  The simple answer to that question is, we don't know. It is quite a common thing amongst Aldabra, so you are not alone and it is not detrimental to the tortoises health in anyway. A number of our own animals have them and it makes no difference to how they treat or are treated by other members of the group.

 

  Usually it is just one mark going across the scute, sometimes it is more, forming x or y shapes. Some are just like scratches, others are deeper and others form protrusions like horns. The visible size and depth of this mark will alter as the animal gets older.

 

  There are two thoughts to the cause of this. The first is that it is an issue with incubation which causes it. However, we think that is unlikely, the breeding parks have been successfully breeding baby Aldabras for a while now, so if there was an issue with their processes then they would have sorted it. Particularly when animals with a split rear scute traditionally sell for slightly less than those without the split. Not being mercenary but that could be quite a chunk of income they loose out in, if it was a problem that could be easily fixed with temperature or humidity levels or something.

 

  That leaves the most likely reason for this happening is that it was down to genetics. Maybe one of the earlier parents had this split scute and they passed it on to their offspring. There would have been much delight that eggs had been hatched so maybe the split was not noticed until the animal was older. Maybe the parents dont actually have a split themselves and they just pass the gene on. It is difficult to say but this split scute is now firmly entrenched in the Aldabra population, in the UK and probably elsewhere in the world and it would be difficult to breed back out again, particularly when there has been no successful breeding in this country yet.

 

  It would be interesting to know if the wild population had it too or if it was just in the ones in captivity, as this would strengthen the thought about it being down to genetics.

 

 

What Is Under The Shell?

   There isn’t A Lot Of Room Inside Their Body Cavity, everything is packed in there quite tightly. for one thing they would not want their insides moving around as they walked because it would upset their balance.

 

   A tortoise is a vertebrate animal. Its backbone is fused to the inside of its upper shell. The shell design has remained almost unaltered in 200 million years of evolution and is basically an extension of the rib cage, which are outside rather than inside the body. Due to the fusion between shell and bones it can make it harder for the tortoises to breathe as the shell is rigid and does not expand with every breath, like human torsos. It is particularly uncomfortable for them to breath if they become obese as there is even less room to expand their lungs

 

   Beneath the protection of their tough shells tortoises have all the usual organs and things; Their liver is unusually large and is about a third of their whole weight of flesh. The shell, which goes all of the way around them, holds everything in place. About 25% of their body weight is fluid, so they don't need to drink during the dry season as they gain their water through metabolism.

 

    Approximately, the top 1/3^rd of their shell is filled with lungs, they are specifically called the Chelonian Lungs because they are more like sponges than big bags of air, which could collapse.

 

    Their respiratory system is driven by a need for oxygen rather than getting rid of Carbon Dioxide like us. This gives them a great ability to hold their breath. One of our big males likes to sit in a water wallow where he can fully submerge his head, and most of his body, we discretely timed him one day and he held his breath for over 7 minutes! this makes them very difficult to safely anaesthetise if they need to go to the vets.

 

   If you startle a tortoise then instinctively it will want to pull its head and legs inside to protect itself. However, in order to fit the head back into the body cavity it first needs to release air from its lungs to make space. the speed of the air being forced out makes a hissing sound, with is not confrontational like it might sound.

 

   The tortoise has an interesting bladder as it can store liquids for longer periods of time in case the tortoise cannot find a reliable source in the wild. A lot of plant matter that tortoises eat contain water to some degree. So, tortoise, depending on the species, can actually live for a good while with no food or water.

 

   Just below the lungs up near the front of the tortoise and working down there is the stomach, liver, gall bladder, kidneys, and if the tortoise is male then the testes right by the kidneys. Under all these organs are the intestines taking up the centre. Up higher in the chest of the tortoise sits the heart, all of this including their fat pads makes up about half of the animals total weight

 

   The shell grows with them all of their life, although active growth is only until they are about 50 years old when they begin to bulk out weight wise.

 

   Tortoises are not like some crabs that shed their shells and then find a new, larger one to inhabit, once they outgrow the first one.

 

   The shell also acts as their very own solar panel system and they usually bask with the rear of their shell towards the sun. It is more efficient that way as there is more scutes to capture the suns rays and who wants to sit with their head exposed in the sunshine and get a headache.

 

   The tortoise’s heart pumps blood to all the vital organs and muscle groups, but a large amount of blood is also effectively sent underneath the carapace to heat up before circulating around the rest of the body to raise its core temperature. optimum body temperature is 30°c for metabolic efficiency. this means they require extra heating in their house to provide a basking temperature of between 25-35°c. However, they do also require cold spots so they can cool down if they want. Too much heat or too much cold is not good for them, they need a happy medium.

 

 

Bing pictures.

Can A Tortoise Die If Rolls Onto Its Back?

   Whilst it is true that when a tortoise fall over onto its back it will die if it cannot right itself. This is not a quick process; the animal will suffer exposure, dehydration, stress, and, as previously mentioned, its own internal body weight crushing down on its lungs slowly asphyxiating it.

 

   It is a good idea to try to teach your tortoise how to right itself whilst it is small, as it is learned behaviour. Therefore, if you find your tortoise on its back don’t immediately rush to right it or else it will come to expect a big hand to come down from the sky to rescue it every time, and will not try to save itself. If it happens when you are not around then the worst can occur.

Instead as the tortoise naturally flails its arms and legs around in panic put your finger or a small rock beside it so that it has something to push against and use to turn itself back over. It will give it the idea of how to get itself out of such a mess in the future.

 

   Take extra care when turning the bigger animals over because they can turn and land with such force that the knees and elbows, furthest away from the ground, can be damaged. Put a cushion or a tyre or something beneath them so that the landing can be more controlled.

 

How Many Bones Does A Tortoise Have

   A tortoise has a total of 52 bones in its body, this is fewer than most other animals, and 20 to 30 of those bones are just in its shell, depending on the species.

 

 

Bing pictures.

 

How Big Do They Get?

   Wild male adults typically have a Carapace shell length of 105cm (41 inches) but can grow to 4ft. The females get up to 3ft (91 cm). Tortoises kept in captivity will typically grow quicker than their wild counter parts as they have access to more food and it is normally of a better quality than food found in their natural home range. However, over feeding them can cause weak bones and other health issues, it is best to allow them to forage and allow them to eat as much or as little as they require. They can spend many hours eating but they can also spend an awful lot longer sleeping the day away.

 

   Wild Aldabra tortoise size varies across the atoll, depending on how much food they have had access to in their lifetime and the type of food can also affect the smoothness of their shell. Too much fruit in their diet can cause pyramiding of the shell.

This is something that tortoise keepers need to be aware of. Too rapid a growth can cause issues such as problems moving due to over weight. Also weak bone structure, which is why captive animals need calcium supplements. Their bones are solid and without marrow inside them.

 

   A regular dosing of vitamin and mineral supplement, on their food, such as Nutrobal, is helpful if the diet is lacking. However, weeds contain plenty of natural calcium, so do not over do it as it is possible to overdose them (not as in fatal overdose!) and create a different set of problems, the key is to give them eveything in moderation.

 

   If an adult Aldabra tortoise stands fully upright, on their four legs, the head easily reaches an adult humans waist. Aldabra tortoises have large feet, like elephants, to help disperse their heavy weight when walking and make them more stable. The limbs are covered in bony scales to protect their soft skin both from cuts and injuries and as a defence against the harsh sun of the Indian ocean.

 

   They are very strong animals and the larger ones are able to carry the weight of an adult human sitting on their back with no trouble, after all the females have to support their weight and the males pressing down on her when mating. however, we do not encourage riding the tortoises- they don’t go very fast and it isn’t very comfortable!

 

   Thanks to a previous, unintentionally over indulged, effortless, lifestyle our big males need to do a little more exercise to build up muscle strength but we are working towards improving their leg strength, it will just take a while. nothing ever happens quickly with these guys.

 

   Aldabras will actively grow until they are about 50 years old and then it becomes more about bulking on the weight rather than physical size, and growth rates becomes more spasmodic. Sexual maturity is down to size more than age. In the UK they are slower to reach sexual maturity, which isn't until they are about 40 compared to about 25 in the wild, when they are about half their fully grown size. This is one of the reasons no one in the Uk has managed to successfully breed the Aldabras yet.

 

How Heavy Are They?

   Adult females are smaller than the males, usually weighing in at about 130-150kg when fully grown. However, the big males can be over a quarter of a ton (250kg).

 

   The heaviest known, free roaming, (wild) Aldabra tortoise ever recorded was a male who tipped the scales at 305kg. We believe there is a male currently living at Fort Worth Zoo in Texas who reportedly weighs 363kg.

 

   Esmerelda, an old free roaming Male, who lives on Bird Island in the Seychelles, was weighed in the 1980’s and broke the scales! registering 298kg. In comparison the heaviest adult Sulcata recorded was a mere 105kg!

 

How Much Do They Grow In A Year?

   The amount of food available affects the number of growth rings the tortoise produces in a year, in a good year they could have numerous rings but in a lean year they do not have energy to spare to grow. New growth rings are added concentrically around each 'Scute' or segment of shell, so the animal grows quite quickly as the size increases exponentially. contrary to popular belief, you cannot count these rings, like you would a tree, to determine the animals age.

 

   During the rainy season the keratin of their shell grows faster than in the dry season, this is another reason why it is unreliable to try and count the tortoises 'rings' on its shell.

 

The Muscular System

   Tortoises have different muscular systems to most other types of vertebrates this is mainly due to their spines being rigid. It means that they don’t need to flex and twist their backbone, so they don’t require those muscles. In contrast they do have very well developed neck muscles allowing them to stretch out to full extension and retract right back into their shells. They also have well developed leg and tail muscles.

 

   Tortoises and Aldabras in particular, can bite through some very tough foods so they have strong muscles in their lower mandibles. This is something you will have noticed if you have ever tried to pry open a tortoises mouth when it is reluctant to eat, it is not the easiest thing to achieve.

 

   A healthy tortoise of any species will have strong muscles, weak flaccid tortoise is not feeling well and needs expert treatment. A sick or stressed tortoise will be reluctant to stand and come out of its shell but a healthy animal will stand tall with their plastrons off the ground, how the animal stands will give you a good idea about how the tortoise is feeling.

 

   An Aldabra that is in good health is a very strong animal, even the babies, and you are never going to win a tug of war against the big guys!

 

What Is Their Heart Beat?

   Interestingly tortoises have a three-chambered heart. Giant tortoises have a resting heartbeat of 6 beats per minute and an average lifespan of 177 years. In contrast mice have a resting heart beat of 240 bpm and a lifespan of just 5 years. Humans average 60-70 bpm and live and average of 70-80 years. This does show that the lower the hearts rate the longer the life.

 

   On their home Atoll the tortoises are not hunted and they do not hunt anything themselves, so they do not have that stress. They move very little when they are eating so they do not need a rapid heartbeat. Even when they are climbing a hill, which is probably the most activity they would get, their heartbeat would only be around 25 bpm.

 

 

Do Tortoise Have Blood?

   Yes, tortoises have blood, even though they are cold blooded reptiles they blood is still red and not blue, and you can see it if they scratch or injure themselves. Their erythrocytes have a central nucleus.

 

   Tortoises are ectothermic animals, which means they need sunshine and shade to warm and cool their body temperature. The heart will first pump the blood through the vessels beneath the plastron so that it can be warmed to approximately 30°C, whilst they are basking and then through the circulation system, within the body to distribute the heat and encourage metabolism.

 

   If you look inside a tortoises mouth they should have a pink mouth and tongue, which indicates they are well. If they are looking pale or dry in there, they are at least dehydrated and need medical attention.

 

   It is difficult to get a blood sample from a tortoise because most of the body is covered in shell. The vet usually tries in the neck cavity or by the rear legs but then they usually pull in and can bend the needle. Some native communities think that tortoise blood has medicinal benefits and that it can cure ailments like anaemia.

 

   If your tortoise is oozing blood, of any colour, from any orifice, then they have a health issue, which could be serious and they need the attentions of a vet.

 

Do They Have A Tail?

   Yes, it is under the back, bottom edge, of their shell and is usually tucked to the side so that it does not impede movement or so that it is not accidentally damaged. The males have a lot longer tail than the females and on adults it will almost reach their back legs, they can tuck it either side but they usually have a preference. Their Testes are located internally.

 

   The tail has strong muscles and both males and females have just one multi-purpose opening, the cloaca, also called a vent, which is used for defecation, urination, mating and for the females to lay eggs. if they start ‘Wagging’ their tail from side to side it is usually an indication that they are about to go to the toilet. Tortoises will either stand up or just raise their back legs, to make room for their tail to hang down, when going to the toilet. They are able to multi task and will quite often still be eating at the same time!

 

Do They Have A Hierarchy?

   Not really, Aldabra tortoises don't have a possessive nature and are quite happy to share food together no matter their size, sex, or age. Obviously due to their greater size and strength the bigger tortoises are able to push their way through, most situations, to get to what they want. If the smaller tortoises are in the way then they get shoved too but it is not with malicious intent.

 

   The smaller tortoises have the advantage that they can get into smaller spaces that the bigger animals can’t reach, so it evens things out well. Samson particularly likes to use one of our smaller animals, Little George, as a pillow, a little hard but each to his own.

 

 

 

Can They Communicate With Each Other?

   Communication between them is restricted, a large part of their body is immovable shell so visual movement communication between tortoises is not that good. They partake in a social contact called ' nosing' when one animal comes close to another and lies down on the ground and gives the other animal a nose rub on its back or the neck. A ritual that can continue for quite some time. There is no clear explanation known about what it means, probably a bonding thing. There is a thought, amongst some scientists, that they emit a sound like elephants, which is out or range for the human ear to hear. Every year more research is being carried out about these animals but there is still a lot to learn. It would not be surprising if they did have a form of communication that we cannot detect.

 

   Although they do go exploring on their own Aldabra tortoises are a herd animal and like the social interaction of being in groups. They have a strong sense of smell so they can use this to learn a lot about their fellow tortoises, particularly when they are looking for a receptive mate. Smaller breeds will also use ‘ramming’ to communicate with anther individual, whether it is to express interest in a female or to show aggression to a competing male.

 

   Interestingly when we got our largest Aldabras they were part of a bigger group, only three of them came to us and the rest were re-homed somewhere else. Years later, we got the opportunity to take on some of these other animals and when the five of them met up again there was no animosity between them, they all settled together really easily, you got the definite impression that they recognised each, other even though they had been apart for nearly ten years.

 

 

 

Are They Intelligent?

   Aldabra Tortoises have a reasonably high intelligence rate and are often compared with a white rat. They can learn and remember things but aren’t the cleverest animals on the planet. However they don’t need to be- they have a very plain and boring lifestyle, they don’t need to get away from hunters or find and catch live prey. They have sufficient intelligence to do what they need to do but the actual brain of a tortoise is extremely small.

 

   In 2020, a female Aldabra Giant Tortoise living on Fregate Island, in the Seychelles,  was observed hunting and eating a juvenile Lesser Noddy, indicating that the species was in the process of learning to catch birds.

 

Gross but interesting

   In the 17th century, there was an Italian, scientific, gentleman called Francesco Redi, who was known as the founder of experimental biology. He performed an experiment that involved removing the brain of a land tortoise, which then proceeded to live for six months. Redi also cut the head off a tortoise entirely, it was still capable of walking 24 hours after decapitation and and it lived for 23 days. Not sure if that applied to the head or the body part though, which ever it is very disturbing!.

 

What Do They Taste Like?

   Aldabra tortoise meat has been described as 'wholesome and not unlike mutton but more delicate. The fat is white and does not congeal and is never known to cause indigestion and is considered superior to the finest butter in Europe. The liver is delicious and very large in proportion to the animal- about 1/3 of the whole weight of the flesh'.

   Never having tasted it, and with no desire to do so, I could not comment but I believe most things taste like chicken.

 

  You may want to demonise the locals for eating the tortoises, in the past, but the fact is that they are a good source of meat to feed your family. Every countries diet will be made up with what is easy for them to produce or farm. Just because we find it distasteful does not mean that it is wrong for them. It is probably very similar to the UK breeding cows and sheep- we have been doing it for many hundreds of years but other religions, and parts of the world, would find us routinely eating these animals completely abhorrent.