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Feeding Tortoises: Avoiding Dietary Disasters


A wild Testudo hermanni hermanni grazes on low-lying vegetation.



Updated Tortoise Trust guidelines for:


Feeding Leopard tortoises - Feeding Mediterranean tortoises - Feeding Redfoot and Yellowfoot tortoises - Feeding American Box turtles - Feeding Russian tortoises - Feeding Hingeback tortoises - Feeding Desert tortoises


Almost no topic is as confused and difficult for a beginner to understand than feeding tortoises in captivity. It is also true that no other subject is as riddled with misinformation and myths. The proliferation of inaccurate and often lethal advice on this subject in books, in magazine articles, on social media and on the Internet is astonishing. It is no wonder that many new keepers find themselves totally confused, and often end up making basic, but serious mistakes that can have devastating consequences to the tortoise concerned. A 'dietary disaster' is something that goes so wrong that it can never be fully corrected. The best that you can hope for is that it gets no worse. The damage done is invariably permanent, and the most unfortunate thing of all is that pretty much without exception ALL of these problems are entirely preventable with good dietary management from the very beginning.


Clearly, the ideal diet for any captive tortoise or turtle would be exactly the same as it

experiences in the wild. For obvious reasons, this is not usually possible, but this does

instantly eliminate some of the more bizarre and grossly unsuitable items which have been suggested from time to time. When anything is suggested as a suitable food to feed your tortoise, it is a very good idea to ask the following question:


Would this particular species eat this (or something very like it) in the wild?
If the answer is “no”, then it is probably not a good idea to include that item in the diet in captivity.

That might sound simplistic, but it happens to have a very sound scientific basis and a strong practical track-record of long-term success with multiple species.


Getting the diet 'right' necessitates an understanding of an individual species nutritional requirements, an understanding of how environment affects nutritional needs, an understanding of basic food chemistry and some knowledge of the vitamin and mineral trace element metabolisms. Unfortunately, many of those who publish advice on this subject seem to lack such knowledge, and hence much of what appears in print and upon the Internet is incomplete, is based upon misunderstandings of these essential principles, or is a gross oversimplification. Whole books can be written on the subject of feeding tortoises and turtles in captivity, and indeed have been. Even genuine experts in this field often disagree upon the finer points. Most do agree on the basic principles, however.


The object of this present article is to 'get you started' with a simple, but safe and effective, basic diet which you can undoubtedly develop and refine further. The focus is on setting some basic ground rules that conform to the principle of 'do no harm'. The guidelines presented here have been developed and tested over many years by the Tortoise Trust. We do not pretend that in the simple form presented here they represent an optimum in every case; they are, however, fundamentally safe and effective in practice. This is a good place to start if you are new to this subject and wish to avoid causing irreparable harm to your animals. More experienced keepers will refine these diets and optimise them for the individual species they keep, taking into account the age of the animal, its sex, alternative foodstuffs that may be available, and local environmental factors among other considerations.


We have also included a short ‘Feeding FAQ’ that attempts to answer some of the questions we are asked most often. Study these carefully.


First, a few important facts:


Variety

In the wild, tortoises tend to be browsers. They wander over a wide area and in the process take small quantities of a very wide variety of seasonally available food. Some species are known to consume up to 200 different kinds of plants during the course of the year. The exact combination of plants, and their status, young, fresh and succulent or old and dry, varies seasonally. Even some true tropical species experience major seasonal (rainy/dry) variations in food availability. Redfoot and Yellowfoot tortoises from South America, for example, will eat a diet comprised almost exclusively of leaves and flowers for part of the year, changing to a diet heavily biased in favour of fallen fruits later in the year. In the case of Savannah and semi-arid habitat species, food availability often peaks during early spring, but is sharply reduced during the very hot summers experienced in such zones. In response, the tortoises may enter a state of aestivation to conserve energy, ceasing all normal activity at such times. A tortoise’s diet changes continually throughout the year. In temperate species, from a fairly high moisture and energy content in spring, to a very dry, and often lower energy content later on. By wandering over a wide area, and by consuming such a variety of foods, tortoises ensure that their overall intake is well-balanced and can supply the essential mineral trace elements that they require for reproduction and healthy bone development. Even the best captive diets tend to be very restricted when compared to these natural feeding patterns.



An excellent diet for a captive-bred Mediterranean tortoise (Testudo ibera) at the Tortoise Trust. These animals live in well-planted outdoor pens that have been seeded with appropriate vegetation that approximates that found in their natural habitats.


Growth rates

High growth rates dramatically increase the risks of metabolic bone diseases in all of its various forms. For a more detailed overview of exactly what happens, see our recent article 'Tortoise Shell Deformities: A View from the Inside'.


In brief, however, while an adult with an already-formed, stable shell and skeletal structure can tolerate a poor diet for quite a long time without immediately showing obvious signs or damage this is absolutely not the case with a juvenile or younger tortoises where growth and development is still taking place. These are incredibly vulnerable to all deficiencies, excesses or imbalances. Over-feeding, and grossly accelerated growth can result in permanent damage, and ultimately in an early death, in a surprisingly short period in such cases, as little as 12 months in some instances. Some of the reasons for this are quite complex, but tortoise behaviour and life-cycles are intimately linked to food intake, and hence, also linked to growth rates. For example, Testudo horsfieldii (the Russian tortoise) is only active for around three months out of every twelve months in the wild. For nine months they are buried, not eating at all. Even when they are active, data from field observations suggests they they only forage for approximately 15 minutes per day. Yet - in captivity, people often force them into a continual activity and feeding cycle all year round. This - naturally - results in massively accelerated growth and is one of the main reasons why we see such disastrously high rates of metabolic bone disease in this species.



For comparison here are two Russian tortoises (Testudo horsfieldii) of approximately the same age. On was reared from a hatchling by the Tortoise Trust using the dietary and environmental guidelines described here, the other was purchased as a pet, kept in a vivarium and forced into a continual feeding cycle. The diet provided in the latter case was lacking in fibre, but was far too high in readily digestible carbohydrates and protein content. It was also high in phosphorus, but low in calcium. The excess growth (pale areas) in the latter case are all-too obvious. We're sure you will have no difficulty in telling which is which.


Even species from less extreme environments such as Testudo graeca graeca or Testudo hermanni spend much of the year either brumating ('hibernating') or aestivating (summer dormancy due to high temperatures and lack of rain). Even in 'peak' activity period there can be cold days when they are not as active as usual. This is being written from a location surrounded by Testudo graeca graeca habitat in Southern Spain, yet today it is cold (10 Celsius or 50F), overcast and is raining slightly. In simplistic terms they too are not active 24/7 on 365 days a year. Some pet keepers immediately rush to get the tortoises inside and under heat lamps in such conditions! This can, however, be very counter-productive. This does vary by species, but they certainly feed for far fewer periods, and in substantially less quantities, than most pet keepers seem to believe. This has a direct effect upon their growth and especially upon the bone densities they are able to achieve. Generally speaking, many captive tortoises have terrible bone density, while almost without exception tortoises in their natural habitats display flawless growth and excellent bone density. In fact, we conducted an 'ad hoc' survey of tortoises pictured on one well-known social media site and found that more than 90% of the Russian tortoises featured in owners posts displayed unmistakable evidence of both excessive growth rates and shell deformities resulting from poor diets and a failure to take their natural life cycles into account. Most of these will suffer severe consequences and very few are likely to survive long-term. Remember, 'long-term' for a tortoise is not four, ten or even fifteen years. It is measured in decades. The best way to avoid these problems is to study the life cycle and the natural diet of the species you keep, and try to replicate it as closely as possible. Forcing tortoises that have limited activity periods in the wild into continual activity/feeding patterns is a sure-fire recipe for a real-life 'dietary disaster'.


In addition, because tortoises are reptiles their digestive processes are also highly dependent upon ambient temperatures. Specifically, temperate species in particular often experience a really big drop in temperatures overnight, especially in spring, when their feeding cycle is at its most active. For example, just a week ago (late April 2024) we measured overnight temperatures next to wild Testudo hermanni hermanni at just two degrees Celsius (35.6 F). This has the effect of slowing down the fermentation-based digestive processes and hence, limits excess growth. In captivity tortoises are often subjected to excessively high overnight temperatures, further driving excess growth and contributing to various forms of metabolic bone disease.

The Tortoise Trust has a separate article on the realities of overnight temperatures for Testudo species: Failure to learn from these natural cycles is a major factor in why so many captive tortoises suffer such devastating 'dietary disasters'. Almost without exception the most extreme examples of these conditions we see are of tortoises that are maintained largely indoors in various forms of 'vivarium' housing.


DIETARY FIBRE

Fibre is required to help a tortoise's digestion, though again this varies according to species. Without an adequate dietary fibre intake arid and grassland habitat tortoises tend to suffer from diarrhoea and loose, wet droppings. Frequently, these problems can be cured simply by increasing the amount of coarse, fibrous vegetable matter provided in the food. Mixed grass and hay is probably the most natural source for some species, and most tortoises from Savannah habitats enjoy it, for example Leopard tortoises (Stigmochelys pardalis) and African spurred tortoises (Centrochelys sulcata) but it is not readily accepted by Mediterranean tortoises. Ideally, it is clear that a mix of fresh green (and some dry), high fibre vegetation based upon flowers and herbs combined with a very high fibre (in the region of 30-40% on a crude fibre basis) coarse supply of dried vegetation supplied on a cyclic basis would more closely approximate the natural diet of Mediterranean and most other semi-arid habitat tortoises.


Typical captive diets supply nowhere near this figure. It can be very instructive to

compare the droppings of wild vs. captive tortoises. There is usually a very noticeable

difference. The importance of this should not be underestimated. It is a critical factor in

obtaining good, healthy growth and development in all species. Wet, runny droppings from a tortoise are a clear indicator that something is seriously wrong, usually either a parasite problem or an incorrect diet. Do not ignore it, but identify the cause and take corrective action. This is such an important topic that we have a separate, in-depth and detailed article on the subject: Dietary Fibre in the diet of the Herbivorous Tortoise Testudo graeca graeca in Spain: Some implications for captive husbandry. See below in the discussion on commercial foods for some simple and practical options that you can use to easily increase fibre intake to more appropriate levels.


Calcium and Vitamin D-3

Tortoises tend to be found in regions where the soils are relatively rich in calcium and other essential trace elements. They also have free access to sunlight for basking. Natural sunlight contains UV-B radiation which is required by the tortoise to internally synthesise vitamin-D3. This is required by the tortoise to enable it to use the calcium it consumes in its food. Without an adequate level of D3, this calcium is useless for building bones. In order to synthesize D3 properly, both UV-B radiation and radiant heat is required.


True rain forest species obviously cannot and do not bask to the same extent as species from deserts or plains. Their diets tend to be very different, in that such species are usually partial omnivores. Much of the vitamin D3 component they require is, in this instance, met from the animal component of their diets. They are therefore far less dependent upon basking than exclusive herbivores. This is merely one example of how environmental factors influence diet, and vice versa.


Tortoises have a very high demand for calcium in their diets, especially when undergoing rapid growth (a juvenile, for example) or in the case of egg-laying females. Such animals tend to actively seek out extra calcium to meet these needs. If it is not available, they can rapidly suffer deficiencies.


This California Desert Tortoise was raised from a hatchling on a high protein, highly digestible commercial 'pellet' diet based around unsuitable ingredients (corn, soy and grain derivatives) together with salads, fruit and 'vegetables'. This promoted excessively rapid growth. The diet was also seriously calcium deficient and far too high in phosphorus, so Instead of developing a normal, rounded carapace shape, it developed the typical lumpy, flattened form characteristic of MBD (Metabolic Bone Disease)


A similar example, this time a Testudo graeca again raised (in a vivarium) and fed on a diet of 'supermarket salads', root vegetables and fruit. The acute depression over the pelvic region is caused by the weak, porous and 'rubber-like' bone of the carapace being 'pulled inwards' by internal muscular attachments.


Habitat and diet

Tropical rain forest species encounter carrion and fallen fruits quite often. It is a typical feature of these environments. Species that inhabit dry, grassland savannahs or arid desert environments hardly ever encounter carrion or fruit, however. Both groups of tortoises have developed different ways of dealing with the foods that they naturally encounter. If you feed arid habitat tortoises fruit it will cause severe digestive tract upsets, diarrhoea, encourage the proliferation of digestive tract parasites such as flagellate organisms, and can even lead to sudden death from a maladjusted gut pH. By the same token, you cannot expect to keep a tropical rain forest tortoise such as an African Hingeback (Kinixys sp.) healthy on a diet of mixed grasses and hays. Such a diet is very well suited to a Leopard tortoise (Stigmochelys pardalis), but is completely unsuited to the needs of a species that has evolved to consume a combination of live prey, soft fallen fruits, and carrion. These are not dietary 'preferences' - they are dietary imperatives. They are not interchangeable. Any attempt to do so invites very serious consequences indeed. These ill-effects may not show up for some time. It can even take years. By the time it does show up, however, it may well be too late to do anything about it.

We cannot stress this enough: learn about the real needs of the species you keep and try to understand the reasons why it has those needs, and then try to find out how best you can meet them.

Commercial tortoise diets

It is worth commenting upon the canned (usually dried) 'complete tortoise diets' that are widely available and heavily promoted in pet stores. These are advertised as complete, or almost complete, solutions to all of your tortoise nutrition concerns. Words such as 'scientifically formulated', 'approved by zoo vets' and 'quality ingredients' are used to describe them. You may think you are safe relying upon such products. The truth is rather different. See our in depth article on these products. We have tested most of these products over the years, and in our view, they should be avoided with very few exceptions (one of these is AGROBS, which is a very good product indeed that can be a genuinely useful and safe way to increase fibre intake). We have also seen numerous 'dietary disasters' attributable to the use of 'mass market' pet-shop sold pellet diets. These products are usually extremely high in digestible energy, encourage over-fermentation, and many contain high sugar levels and totally unnecessary and counter-productive 'probiotics' in addition. They in no way approximate the natural diet of these animals. Rather than describe each one in detail, we will let the following picture speak for itself. This Terrapene carolina (American box turtle) was raised on a diet advised by a resident 'reptile expert' at a pet store. A mass-market pelleted food and mealworms.


Note the severe deformity here: a condition typical of animals raised on high protein, high growth rates and inadequate levels of calcium. Feeding mealworms in excess to these species is another common cause of this same condition as they are extremely high in phosphorus but very low in calcium.




A Stigmochelys pardalis (Leopard tortoise) raised from a hatchling on the diet recommended by the Tortoise Trust. Note the very smooth carapace and even growth.


Our advice is simple. We see no need for these mass-market commercial 'pellet' products and we believe their use is unsafe and is very likely to lead to the kind of severely deformed animals shown above. We strongly recommend that you avoid them. If you do use them, study the ingredients carefully. Avoid all that contain soy or grain-based items, fruit or vegetable derivatives, strange and undocumented additives, or are made from highly processed fibres. All of these can cause serious and irreversible damage quite rapidly. Look instead for minimal processing, the preservation of coarse, long fibres and freedom from inappropriate and unnatural ingredients or unproven additives.


Unfortunately most of the 'mass market' foods include totally unsuitable, unproven and potentially damaging ingredients. We highly recommend entirely avoiding MAZURI, T-REX, ZOOMED, PRO-REP, KOMODO, ARCADIA and REP-CAL pelleted products.

There are, however, some much safer commercially available products that can be genuinely useful. These include seed mixes designed for herbivorous tortoises that you grow yourself in outdoor pens, and various pre-packaged dried leaves and flowers. These can add variety and will greatly assist with increasing essential fibre intake.


Unlike ultra-processed, typical commercial 'tortoise foods', items such as these undergo minimal processing and preserve the essential long, coarse fibres intact. That avoids accelerating digestive fermentation and contributes to a normal, healthy gut function.


One of the best known of such products is the Agrobs Alpin and Testudo diets (original, fibre and herbs). These differ from most others in that they are minimally processed to preserve the critical coarse, long fibres, do not include unnecessary, unproven or potentially damaging ingredients and are based upon low protein natural meadow grasses and herbs. They are also free of artificial colourings, flavourings or preservatives. The Tortoise Trust has no affiliation with the manufacturer whatever, but we have tested these over many years now and can confidently recommend them as safe and effective.


Agrobs Testudo original in both dry and hydrated states. When hydrated this can be added to fresh graze or supplementary feeds to greatly increase the overall fibre content of the diet.


Most variations are supplied as compressed 'cobs' that can then by hydrated by soaking in water for 10-20 minutes before use. Their extremely high fibre content is immediately obvious. Some tortoises can be resistant initially to accepting new diets, so a gradual introduction by mixing the hydrated cobs with fresh edible 'weeds' is a good way to transition. This can take some time, but tortoises will not starve. They get used to it eventually. The prepared diets should be used in combination with fresh graze on a daily basis. This dramatically increases the fibre content of the diet, helps to prevent excess fermentation and growth, and provides an excellent range of trace-elements with a good calcium to phosphorus ratio. Our experience is that tortoises raised with this dietary combination, in conjunction with the correct environmental conditions, grow very smooth shells and do not suffer from any of the forms of metabolic bone disease sadly so often seen in animals on 'salad' diets and in unsuitable vivarium housing.


FEEDING MEDITERRANEAN TORTOISES

The diet of Mediterranean tortoises (Testudo species) in the wild consists almost entirely of herbaceous and succulent vegetation, including leaves, grasses and flowers. Fruit is categorically not a regular or significant component of their diet. These tortoises are almost exclusive herbivores. They categorically do not consume animal proteins of any kind in the wild, other than - possibly - on a very (very) rare and opportunistic basis. It is in no way a regular part of their diet. High protein content vegetable Items such as peas, beans are also highly damaging to herbivorous tortoises. High protein foods result in a dangerous increase in blood urea levels: This causes renal stress, greatly amplifies the risk of bladder 'stones' and can lead to complete kidney failure. It is also a contributory factor in a very unpleasant condition known as articular gout where concentrated uric acid deposits infiltrate the joints of the limbs. This is painful and disabling, and can result in very serious complications.


Although Mediterranean tortoises will take animal protein if offered (as will most normally herbivorous tortoises), in practice this leads to excessive growth and causes severe shell deformities, liver disease, and renal stress. It should therefore be avoided entirely. In our experience, herbivorous tortoises that are fed animal protein suffer premature mortality. In other words - it kills them.




Look closely at this picture: it provides a rare insight into what Mediterranean tortoises really eat. This is a wild Testudo ibera in Turkey. There are no fruits here. There is no carrion lying around. There are no 'treats'. The shell, however, is absolutely perfect!



Outdoor pens planted with edible 'tortoise seed' mixes. In enclosures such as this Mediterranean tortoises can graze under near-natural conditions and may require little, if any, supplementary feeding throughout their entire season of activity.


Drinking

During episodes of rainfall tortoises will drink from the puddles which form, and they may also approach streams or ponds. They frequently pass urine at this time as well, and will simultaneously dispose of the chalky white uric acid residues which form in the bladder. It is categorically not true that wild tortoises rarely drink. I have seen both Testudo ibera in Turkey, and Testudo graeca graeca in Morocco approach streams and ponds and drink copiously, in addition to regular observations of drinking following rain.


In captivity a source of fresh, clean water is advised at all times.


General rule for feeding Mediterranean tortoises

In captivity, a high fiber, low digestibility, varied plant-based and calcium rich diet will ensure good digestive tract function and smooth shell growth provided suitable environmental conditions also exist.


  • Mediterranean tortoises fed on cat or dog food, or other high protein food items such as peas or beans, frequently die from renal failure or from impacted bladder stones of solidified urates.

  • Avoid reliance upon ‘supermarket’ greens and fruits which typically contain grossly inadequate fiber levels, excessive phosphorus and are too rich in sugars.

  • Avoid the use of root vegetables which are too-digestible and again, poor in calcium but dangerously high in phosphorus.


Excellent example of smooth shell growth in a Testudo graeca graeca graeca on a 100% herbivorous, high fibre, high calcium diet.


We do not use fruit at all with our Mediterranean tortoises and we suggest you do the same. Unfortunately, it is all-too-common to see totally inappropriate and dangerous advice on feeding these species. One veterinary website published a truly appalling diet for Mediterranean tortoises, heavily biased towards root vegetables and fruit (both of which cause major gastric disturbance in these species), including peas and beans which are far too high in protein and have a terrible calcium to phosphorous ratio. It also finished up with recommending meat and boiled eggs. We have also seen many other such examples of awful feeding practices in zoos and similar institutions where you would think that they should know better. Evidently not.



Although it is difficult to tell, due to the extreme deformity, this is a Marginated tortoise, Testudo marginata. For comparison we include a healthy and well-grown example. This animal was also raised on a high protein, highly digestible calcium deficient diet and a low-grade commercial pellet intake This is a terrible example of what poor dietary management will do to a naturally herbivorous tortoise adapted to live on a low energy, low-digestibility and high calcium diet.


Because they grow quite rapidly, and are actually developing their bone structure in the process, juvenile tortoises are exceptionally likely to suffer serious consequences from dietary mismanagement. There is no room for error at all when feeding hatchlings and juveniles. Just a few weeks on an incorrect diet can result in irreparable harm.


A fully grown adult may survive longer, even on a truly terrible diet, but it too will slowly suffer serious liver and kidney complications over the medium-long term. Herbivorous reptiles are not equipped to deal with large amounts of saturated fat, or with high protein, highly digestible diets.

This also covers the point that you will often see people say that they have given some totally unsuitable food to their tortoise '"for years" with "no ill effect''. These are invariably pre-existing adults. Those same unsuitable items fed to a still-growing juvenile will have a very different result, and very quickly too. There is a degree of tolerance, especially to metabolic bone diseases, in adults that simply does not exist with still-growing hatchlings and juveniles.


When planning a diet for captive tortoises, take their natural dietary behaviour into account as fully as possible. In the case of Mediterranean tortoises, try to provide a mixture of edible flowers and leaves. A lack of dietary fiber, or roughage, will precipitate digestive tract disturbance, diarrhoea and an apparently much increased susceptibility to flagellate and other parasite problems.


Root vegetables are far too high in readily digestible carbohydrates, and also have no place whatever in the diets of these species. Mediterranean tortoises should really be viewed as 'goats in a shell', and are similarly adapted to do best on what at first sight may appear to be a very 'low quality' diet in mammalian terms.



Captive-bred Russian tortoise (Testudo horsfieldii) raised by the Tortoise Trust exclusively on a herbivorous diet based upon the guidelines (both nutritional and environmental) discussed here; high fiber, no fruit, rich in calcium, low in digestible carbohydrates, low in protein, no animal matter, and containing a wide variety of fresh and dried edible 'weeds'.

Allowing Mediterranean tortoises to forage and graze naturally outdoors helps the tortoise to maintain good digestive-tract health, and greatly assists in the prevention of obesity. If scute pyramiding is noted, this usually indicates that either too much of the ‘right’ type of food is being consumed, or, more likely, that the overall energy content of the diet is too high and the calcium/UV-B provision is inadequate. As noted elsewhere, other factors are also involved such as excess exposure to the intensely drying effect of artificial heat lamps also plays a role. A 'raw' calcium carbonate supplement may safely be used on a frequent basis.


If the tortoise is maintained indoors for any significant period, be sure to make provision for UV-B exposure. If you keep Desert tortoises (Gopherus agassizii) you will find that the above diet is also suitable, with minor modifications, as their requirements are very similar indeed to the Mediterranean Testudo species.


A really well-grown Centrochelys sulcata (African spurred tortoise). No 'humid hides', no commercial 'junk' pellet foods, no fruits, no 'vegetables', just a very good outdoor environment in a suitable climate and a very high fibre, calcium-rich diet based on natural forage,


FEEDING LEOPARD AND SULCATA TORTOISES

For large savannah species, such as Centrochelys sulcata (African spurred tortoise) or Stigmochelys pardalis (Leopard tortoise), coarse grasses and hays are a critical dietary component. Aldabra and Galapagos tortoises also do extremely well on this type of diet. Some other species also benefit from the inclusion of both fresh and dried grasses in their diet - although certain species, such as Redfoot, Yellowfoot, Hingeback and Mediterranean tortoises are ill-equipped to digest the high silica content of grass fodder. For species adapted to it, however, grass is not only nutritious, but its fiber content makes a significant contribution to digestive health. For leopard and African spurred tortoises, mixed grasses and meadow hays should comprise approximately 70-75% of the total diet.



A Centrochelys sulcata enjoys a meal of mixed meadow hays. Hay forms an important part of the diet of this and other grassland species.


Availability of grass types varies greatly according to location. The following list of suitable fodder grasses is based upon availability in the USA. In Europe, these particular species are rarely available - although local equivalents can usually be found. General 'meadow hay' and 'orchard hay' mixes are usually suitable, for example. Avoid hays that have excessively 'prickly' seed heads - these can injure mouths or eyes. The use of coarse Timothy hay is excluded on this basis. Second or third cuttings of grass hays tend to have less spiny heads than first cuttings.


· Buffalo grass

· Couch grass

· Kikuyu grass

· Dallas grass

· Blue Grama grass

· Big Bluestem grass

· Darnel Rye grass

· Wintergrass or Bluegrass

· Western Wheatgrass

· Fescue sp. grasses


This grass-based primary diet should be supplemented with flowers and edible succulents as frequently as possible. Again, as with Testudo species, fruit is inappropriate and can be rapidly damaging to these tortoises. This is discussed in another in-depth article on this website: Fruit for Arid Habitat Tortoises - 'Treat' or Tragedy?


Indian star tortoise (Geochelone elegans). The diet for this species is quite similar to that of Leopard tortoises.


FEEDING INDIAN STAR TORTOISES

Indian Star tortoises (Geochelone elegans) have dietary requirements that fall mid-way between that of Mediterranean tortoises (Testudo species) and Leopard tortoises (Stigmochelys pardalis). In captivity, they should not be given fruit either in quantity or on a routine basis, or they will suffer serious digestive tract disorders. They need a diet which is very high in fiber, is low in sugars and easily digestible carbohydrates, and which is primarily based around coarse green leaves, mixed grasses, and flowers. Juveniles and egg-laying females require large amounts of calcium and adequate exposure to UV-B and basking temperatures.


Avoid diets based upon 'supermarket salad'. This will not offer adequate fiber, and tends to be very poor in essential trace elements and other nutrients. Thousands of baby Indian Star tortoises are sold each year in some parts of the world as pets: the vast majority die within 12 months because the basic feeding advice given here is ignored. If you keep this species, you must provide an adequate diet and you must ensure that both calcium and UV-B needs are met.


FEEDING REDFOOT, YELLOWFOOT AND AFRICAN HINGEBACK TORTOISES



A wild Hingeback tortoise (Kinixys belliana) enjoys a meal of a live snail (photographed in the field, in South Africa). Snails and millipedes are a regular part of their diet.


These tortoises are omnivorous to a greater or lesser extent depending upon species. Include a small amount of low-fat animal protein in the diet of these species. It is no coincidence that all species with this class of diet occur in high rainfall, high humidity ecosystems with regular access to free water. This is reflected not only in their digestive tract biochemistry, but also in the manner in which they eliminate the waste products of the protein metabolism; tortoises from habitats where water is plentiful are predominately aminoureoletic, excreting a combination of ammonia and urea, while tortoises from arid environments are predominantly uricotelic, excreting uric acid and urates. A suspected protein (or more probably, an amino-acid) deficiency has been noted in some Redfoot and Yellowfoot tortoises raised on entirely herbivorous diets. We recommend re-hydrating low fat dried cat foots with additional minerals and vitamins as for turtles. Provide one meal per week containing animal protein. We now give about 25g (1 ounce) of moist low fat cat food to a fully grown (10 kg/ 22 pound) Red-foot tortoise on a weekly basis (proportionally less for juveniles).


Redfoot tortoise, Chelonoidis carbonaria.


Fruits are also a seasonal part of the diet of these species in the wild and unlike Leopard or African spurred tortoises, their digestive tract copes easily with this richer, carbohydrate-rich intake, comprising up to 70% of the total diet during the wet season and approximately 40% during the dry season. Fruits are normally consumed in a very ripe state after they have fallen from the tree. Some wild species consumed include: Pasiflora coccinea, P. vespertilio, Ficus sp., Philodendron sp., Spondias luteas, Duguetia surinamensis, Mauritia flexuosa, Pouteria hirta and Brosimum potabile. After fruits, flowers are the second most popular food of the Red-foot tortoise. Favoured flowers in the wild include Jacaranda copaia, Mauritia flexuosa and Cholospermum orinocense. During the dry season, such flowers constitute up to about 25% of the diet of this species. The rest of the diet (about 20%) is comprised of green leaves and stems and, (a further 20%) miscellaneous fungi, mosses, termites and carrion.


The same frequency for provision of small amounts of animal protein seems to suit Hinge-backs, which are also highly omnivorous in nature, but here approximately 5-10 g of animal protein per week is more appropriate (depending upon size). It is also important to note that these tortoises, if allowed access to a damp, moist garden or well vegetated tropical house will usually find slug, snails and night crawlers for themselves. This is both psychologically and gastronomically stimulating for them in addition to helping out with their owners' garden pest control efforts! Needless to say, never use slug pellets or other toxic chemicals in any garden where tortoises (of any sort) are kept. Millipedes and similar invertebrates constitute an important part of the diet of Kinixys sp. in nature.



It is a common myth that omnivorous tortoises do not suffer from nutritional disorders to the same extent as herbivorous species. Not true. This African Hingeback tortoise was raised on a grossly calcium deficient, phosphorus-rich diet that was far too high in protein and readily available energy content.



FEEDING AMERICAN BOX TURTLES




These North American semi-terrestrial turtles are also omnivorous in their feeding habits. In the wild, they consume slugs, snails, earthworms and similar small prey as well as fallen fruits, mushrooms and some green leaf material. Juvenile box turtles are often almost exclusively carnivorous, their diet broadening out to include more vegetable matter with increasing age.


· Slugs, snails

· Earthworms, waxworm larvae, mealworms, night crawlers

· Beetles

· Fruit (most turtles prefer “mushy” over-ripe fruits rather than fresh)

· Green leaf vegetables

· Mushrooms

· Small quantity (low fat) dog food, thawed pinkie mice (for T. ornata)


As with all tortoises and turtles, great care must be taken to ensure a varied diet adequate in all essential trace elements. Regular supplementation of the diet is therefore recommended - extra calcium supplementation during their carnivorous phase is especially critical.

PRACTICAL GUIDELINES


  • Try to ensure that all diets are as varied as possible, but only using appropriate ingredients for the species in question. In this manner a wider cross-section of natural trace elements will be made available.

  • Do not dose with 'pure' vitamins unless under veterinary direction - some pure vitamins, including vitamins A & D, are highly toxic if taken in excess. These should only ever be used as part of a treatment program to correct a properly diagnosed specific deficiency.

  • The best calcium supplements for tortoises are phosphorus-free, and are free of added amino acids. Pure calcium carbonate is recommended.

  • If you maintain tortoises outdoors in a geographical zone where natural UV-B irradiation closely approximates that of the habitat in nature, then you should not need to provide additional oral D3 supplementation, though calcium should still be provided. Even in areas with lower UV-B levels these lower levels are compensated for by virtue of the fact that the tortoises tend to spend longer periods in full exposure, so overall, still attain very satisfactory levels (in the natural zone high temperatures limit exposure periods). For more on this see our separate article.

  • Aim for a high calcium, high fibre, low phosphorous content diet for semi-arid or grassland species. For tropical species, carefully research that precise species natural diet and try to approximate it.


TORTOISE & TURTLE FEEDING FAQ


These are real questions from real tortoise keepers. If you have a similar question that requires answering you can submit it to us at tortoisetrust@me.com .We cannot promise to answer it here, but if it is of general interest we may do so.


Q. I understand the need for a calcium supplement, but can I use egg-shells? I read somewhere that these are a very good source of calcium.


A. Eggshells are not a good source of calcium, in fact. They can also contaminate your animals with salmonella. A far better, safer source of calcium is plain calcium carbonate. This can be obtained very cheaply, in bulk, from animal feed stores. You can also use any food-grade calcium supplement, or any phosphorus-free specialty reptile supplement. We strongly recommend avoiding the use of poultry eggshells.


Q. If Mediterranean and Desert tortoises do not eat meat, where do they get their protein from? I thought they needed at least some meat so that they got some protein in their diet?


A. Flowers, leaves, seeds and grasses contain perfectly useable levels of protein, especially for the slow fermentation-based digestive tract of these tortoises. Think about some of the largest mammals around, elephants and giraffe! They are also exclusive herbivores and easily meet all of their protein requirements from the vegetation they graze upon. It is a common misunderstanding to assume that 'meat = protein' and 'vegetables = no protein'. This is completely untrue. Even some vegetable matter can be dangerously high in protein for tortoises; peas, beans, alfalfa and beansprouts in particular are far too high to be used safely.


Q. One veterinary website I visited says that tortoises should be given fruit regularly, other sites disagree. Which is true?


A. None of them are correct. The problem here is that the term 'tortoises' is being used in a far too general sense. You just can’t do that. There are many different species, from vastly differing habitats, and they each have individual needs. Some tropical species eat fruit regularly. It is part of their natural diet and causes them no harm at all - they are adapted to it. The Yellowfoot tortoise, Chelonoidis carbonaria, is a good example. Other species, usually from more arid environments, hardly ever consume fruit in nature, for example, Testudo graeca or Centrochelys sulcata. These species are not well adapted to it, and if it is given, they can suffer very serious consequences, including severe diahrea, colic, and imbalances of the gut pH (acidity), acute cases of which can result in rapid death or major damage to the gut walls. Be very careful when reading advice which is framed in such inaccurate and general terms. Always seek species-specific advice and avoid advice which is so generalised as to be useless, or even dangerous.


Q. The same website states that according to numerous publications Tortoises and Turtles eat a variety of foods - mainly vegetarian, but in the wild they sometimes eat meat such as dead mice or birds and they also eat various invertebrates such as crickets and worms.


A. This is another gross generalisation, and is factually incorrect insofar as many individual species are concerned as numerous highly regarded field studies conclusively demonstrate (Hansen, Johnson and Van Devender, 1976, Swingland, 1984, Luckenbach, 1982). There is not one credible field study that we are aware of that supports the view that in nature species such as Testudo graeca or Gopherus agassizzi consume animal protein on any kind of regular basis. They are herbivores, plain and simple. There are not “numerous publications” that demonstrate these species eat “dead mice, birds or crickets” in the wild ether. You only have to spend time in these habitats to realise that dead mice, birds or other carrion is not just lying around freely. Even if it was, far more efficient scavengers would get to it first. Stating that “tortoises eat a variety of foods” is completely meaningless as pointed out previously. Tortoises will typically eat almost anything that is placed before them in a captive situation. This does not mean that it is therefore safe or appropriate or that they would encounter the same items in nature. In simplistic terms, a child may be happy to exist on a diet of fries, burgers and candy - but this is certainly not healthy and in no way constitutes a balanced diet.


Q. I have been told that excess fibre intake can lead to distension of the gastrointestinal tract - bloat - and that I should avoid feeding too many high fiber foods, is this true?


A. That terrestrial herbivorous tortoises in nature consume very high fiber intakes compared to captive animals is easily confirmed by faecal-pellet analyses. Donoghue and Langenberg (in Mader, 1996) state: “Dietary fiber is a concern when feeding herbivorous reptiles. Tortoises on low fiber diets (less than about 12% DM) have loose faeces. Although it is not well-documented, low-fiber diets may also predispose herbivores to bloat and/or lactate induced diarrhoea from too-rapid fermentation of carbohydrate”. Far from too much fiber being a concern, then, the opposite is the case according to Donoghue and Langenberg. Wet and loose faeces is in fact a typical characteristic, as any competent keeper can attest, of ‘supermarket salad and fruit’ based diets. Jarchow (1984) published a detailed analyses and comparison between a diet based on supermarket produce (lettuce, kale, mustard greens, chard, tomatoes, endive and green beans) and reported crude fiber contents ranging from 6.8 to 14.1%. An equivalent analysis of typical wild foods revealed a crude fiber content ranging from 9.3 to 36.9%, with an average well above 20%. Hansen and Van Devender, conducting a similar study, found wild tortoises consumed vegetation with an average DM fiber content in excess of 30%. Jarchow concludes that diets based upon ‘supermarket produce’ items fail to supply adequate levels of crude fiber to herbivorous tortoises, and also fail to supply adequate levels and ratios of calcium. This is an opinion we unreservedly endorse. The facts speak for themselves.


Q. My tortoise has a white, chalky discharge with its urine. I was told this means it is suffering from too much calcium in the diet - is this true?


A. No. Definitely not. This is uric acid, and it has nothing at all to do with calcium. It is a by product of the protein metabolism in reptiles and in birds. If it is concentrated and thick it suggests one of two conditions: an excess of dietary protein, or dehydration. It is normal to see some uric acid, but too much requires investigation and a possible change in your husbandry practices.


Q. Why should I choose a 'phosphorus free' supplement rather than a supplement that contains a 2:1 ratio of calcium to phosphorus? Isn’t phosphorus important too?


A. Yes, it is. It is also very abundant in just about all green, leafy plants, and there is therefore no need at all to provide any more. It is calcium that tends to be seriously deficient in herbivore diets, not phosphorus. By using a 2:1 ratio supplement, you may increase the overall amounts of calcium and phosphorus available to your tortoise, but you will do nothing much to improve their ratio. You need an absolute minimum ratio of 2 parts calcium to 1 part phosphorus. This is a minimum, not an optimum ratio. We aim for a minimum 3:1 ratio. Many self-selected items in wild tortoise diets have a 5:1 ratio or better.


Q. Is it OK just to use calcium carbonate as a supplement, or should I be concerned about other trace elements?


A. Adding calcium carbonate is a safe way to prevent calcium deficiencies (provided vitamin D3 is also available) and the calcium/phosphorus content of the diet is within safe limits for the species in question. You are correct, however, in pointing out it will not help with other potential mineral deficiencies. A varied, but suitable, diet is the best solution to that issue.


Q. I keep a Centrochelys sulcata (African spurred tortoise) and I live in Arizona. My tortoise is outdoors almost all year. He is doing well, but I worry if I need to provide an oral D3 supplement in addition to the calcium I have always provided daily?


A. You are fortunate to live in an area with a high concentration of sun-loving reptiles and many days a year of cloudless skies! Like your tortoise, they are successfully synthesizing their D3 requirements from the UV-B component of solar radiation. In your situation, we believe you have no need of any oral D3 supplementation.


Q. Many books I have read suggest that I should use a vitamin-A supplement regularly? What do you think?


A. On a good diet, as suggested above, this is not necessary. Certainly, we do not advise use of ‘pure’ vitamin A or D supplements as there is a possibility of overdose with all of the fat-soluble vitamins if used in this manner.


Q. Can I use ‘liquid sunshine’ D3 drops instead of spending all that money on expensive UV-B lighting systems?


A. We absolutely do not recommend products like this. They are potentially very dangerous (see answer to vitamin-A question, above). Overdoses are very possible with ‘pure’ D3 products. Avoid them.


Q. Can tortoises become overweight?

A. Yes, they can. Species which naturally have very short annual activity cycles, due to hibernation, estivation, or both are especially susceptible to problems of this nature resulting from the excess or ‘glut’ of food available in captivity. Species such as the Russian tortoise (Testudo horsfieldii) and Centrochelys sulcata (African Spurred tortoise) are notoriously difficult in this regard. We have seen some truly obese examples. In fact any tortoise maintained on a really inappropriate diet will become overweight, and ultimately may suffer from fatty infiltration of the liver. Any diet that is high in saturated fat is almost guaranteed to produce this outcome in an herbivorous tortoise.



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(c) A. C. Highfield/Tortoise Trust 2024



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