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Mediterranean Tortoises: How much to feed?

By A C Highfield


     We receive a considerable number of questions on the subject of how much to feed juveniles. We have selected one very typical letter which highlights the problems we all face when attempting to raise healthy animals with 'perfect' shell development.

Tortoise Trust member Nigel Budd asks:

     "I'd be very grateful if you would offer some advice on the feeding of my two T. graeca graeca juveniles which we hatched out at the beginning of October from eggs laid by our female. I've been following the advice from your books and web site plus various other sources of information. However I can't find any guide to the amount of food they should consume daily except one book I purchased recently from the BCG which recommends about a "teaspoon" of food daily for the first few months, far less than we've been feeding them. These are our first hatchlings and we are keen to ensure they remain healthy and don't develop lumpy shells. They are fed once a day on a mixture of freshly picked clover, sow thistle, dandelion, plantain and bindweed. I don't have accurate enough scales to accurately weigh the amount of food so a very rough estimate would be about 4 clovers, two medium dandelion leaves, one plantain leaf, half a bindweed leaf and a sow thistle leaf. These are lightly sprinkled with Nutrobal and Calcium Powder Plus. They also have access to cuttlefish though they never seem interested. They are housed in a tortoise table and have 3" loam based substrate with some rocks, slate and a bark "house". Heating is provided by a 60W spot light in one corner providing a spot temperature of around 30 degrees for basking and a 5% UVB fluorescent tube along one edge. We soak them for 5 minutes in warm water every day. They weighed around 10g after hatching and now after 3 months weigh between 25 and 30g and are both 47mm in length.

     Both hatchlings appear active and healthy, although one has a slightly bumpier feel to it around the growth rings on each scute. I'm concerned that this might be the start of lumpy shell syndrome. At what age would lumpy shells start to show? I know it's not an exact science, but any advice on the amount of their daily food intake would be greatly appreciated. Should I also include small amounts of fruit and vegetables in their diets?"

The Tortoise Trust answers:

     Your general set-up sounds excellent, and your dietary regime is also good, though be careful with bindweed (Ipomea sp.); which can contain LSD-related hallucinogens and potentially toxic levels of nitrates and oxalic acids. I would avoid use of fruits and other vegetables, and instead try to provide more flowers.

     The reason we have never provided a 'recommended quantity' to feed juveniles is quite simply because there are so many variables involved, and we feel that any such guidelines are as likely to mislead as to help. Some of these variables include

  • Basking and background temperatures
  • Amount of daily activity (influenced by temperature and light levels)
  • Precise make-up of the diet (protein, fiber, mineral content, etc.)
  • Genetic factors (see below)
  • Competition and behavior within a group

     Each of these has a major impact upon nutritional requirements, and clearly, is almost impossible to assess except on a highly individual basis. Therefore, attempts at formulating a "general rule" is difficult in the extreme, if not impossible. It would be excellent if it were as simple as stating "a 6 month old juvenile weighing 50 grams requires 2 grams of fresh green leaves and flowers a day" - but unfortunately, it is not that simple! Let's look at genetic factors, for example. Even within the Mediterranean Testudo complex there are huge differences in early phase growth patterns. Jill Martin, who manages our own breeding projects, makes the following observations:

Testudo hermanni

     Grows at a far more rapid rate than T. ibera, even on the same feeding regime. Not easy to grow absolutely smoothly if constant access to food and high temperatures are provided.

Testudo graeca graeca (including Libyan race and Moroccan animals)

     Rapid early phase growth, comparable to T. hermanni, but considerably easier to grow smoothly. Easier in this regard than T. ibera

Testudo marginata

     Relatively easy to grow with smooth carapaces, provided adequate D3 and calcium is available and protein levels are within limits.

Testudo ibera

     Very susceptible to 'lumpy shell' problems, and difficult to control. Problems soon develop on diets even marginally high in protein (or if overfed, which amounts to the same thing).

Testudo kleinmanni

     The same observation applies. Very difficult to obtain perfectly smooth growth, as almost any captive dietary regime is likely to verge on excess due to lack of estivation periods and the highly cyclic feeding patterns typical in the wild.

     We find, therefore, that even on an identical feeding regime, with identical environmental conditions, growth rates vary considerably according to genetic origin. It is easier to grow a North African Testudo graeca graeca smoothly, and more rapidly, than it is to grow a Testudo ibera from Turkey, for example. Interestingly, those species which are the most difficult to grow smoothly tend to be from regions where a summer estivation and a winter hibernation (or at least, slow-down) occurs. This reduces the total food intake per year quite dramatically - something few captive juveniles experience.

     In the wild, there are periods of food abundance (spring, for example) and of food scarcity (the heat of summer). In most Mediterranean countries, juveniles tend to hatch in September. This is by no means when food availability is at is peak, but there is usually sufficient for survival (combined with the absorbed yolk sac which is capable of sustaining them, even in the absence of additional food, for quite some time). Within a couple of months or so, many are already facing their first hibernation. Their first major feeding cycle often does not occur until the following spring. At that time, food is plentiful and growth rates are rapid. In most captive situations, feeding tends to be more or less constant from the moment of hatching - this has important implications for growth rates, bone density and other physiological aspects of development (early sexual maturity, for example). As you can see, there are many variables, and it is extremely difficult to quantify an individual animal's minimum or optimum needs! Personally, I feel that "a teaspoon" a day is likely to be too little one day, and too much the next. Instead, I would recommend constant re-assessment and adjustment, guided by careful observation. If growth is excessive and problems are manifesting, try reducing temperatures on alternate days to slow activity and reduce demand. I tend to prefer this approach to imposing strict diets on hungry tortoises. Provided weight is stable, or increasing slowly, and the animal is in good health generally, environmental control of food demand is, I feel, a safer and more effective solution than applying artificially strict rations. Some "off days" for feeding more closely mirror natural patterns, and in our experience, contribute greatly to slow, smooth growth with excellent bone formation and long-term survival. Your chosen substrate is a great help in this respect, as it does provide a facility for microclimate utilization (via burrowing). In addition to helping to regulate growth and activity, burrow use will also reduce the dangers of bladder and kidney stones due to dehydration. Use of as outdoor accommodation as possible is also recommended. The amounts you are offering sound fine to us - we would continue with similar quantities, but would take a close look at managing demand by means of environmental means, as described above.