A C Highfield
Of all the difficulties encountered by turtle enthusiasts, that of raising healthy young animals without carapace deformity is without doubt the most problematic. It is not that information on this subject is absent, but more a case of so much of that information being contradictory; the newcomer to breeding turtles may be forgiven for feeling confused. The following guide-lines have been developed and tested over 8 years with a variety of species including Testudo graeca, T. hermanni, T. ibera, T. marginata, T. horsfieldi, Geochelone pardalis, G. sulcata, G. (Chelonoidis) carbonaria, G. (C). denticulata, G. (C). chilensis and Geochelone gigantea. This basic set of rules also works well with Gopherus agassizzii (Desert tortoise) and Testudo kleinmanni Before turning to the positive steps which can be taken to ensure a natural, healthy growth pattern it is worth looking in some detail at the causes and effects of incorrect dietary management. These may be summarised as follows;
Most tortoises and turtles, will, if overfed either in terms of sheer quantity or quality of feed, demonstrate a quite phenomenal growth rate out of all proportion to that attained under natural conditions within the same time scale. In the case of hatchlings, after 12 months, captive bred specimens may be 300 or even 500% larger than wild equivalents of the same age. This 'gain' is not without its costs. Greatly accelerated growth of this order places a considerable strain upon the overall metabolism, and further results in an extremely high (and often in practice, often unattainable) demand for sufficient mineral trace elements to permit bone formation. Some species are worse than others in this respect - Testudo hermanni hatchlings for example are notoriously voracious. New evidence also suggests that hatchlings and juveniles have a higher digestive efficiency than adults; in other words, they need to eat less for the same benefit. This also means that if they overeat, the results will be far worse. This evidence is backed up by observation. It is indeed the case that over-fed juveniles tend to have very poor long-term survival prospects.
This problem is closely associated with excessive growth. Lumpy shells are caused directly by providing too much dietary protein, by overfeeding and by an incorrect balance of calcium, phosphorous and vitamin D3. The problem is entirely preventable with good dietary management.
Swollen eyes and poor skin condition
Tortoises in general do not make good vivarium animals. They react quickly (and badly) to incorrect environmental conditions. If subjected to conditions which are either too dry or too damp then eye, nose and skin problems are rapidly encountered.
The following basic guide-lines are brief, but effective. For more information on specific topics please see other caresheets in this series or consult the recommended reference works.
Feed once per day only. Do not overfeed. It is better for hatchlings to be slightly hungry than over-fed. Tortoises which are over-fed are lethargic and unhealthy. Over-fed hatchlings will grow too rapidly and may develop 'lumpy' shells.
Avoid feeding excessive quantities of fruits or 'soft' leaves such as lettuce - coarse weeds (vetches, dandelions, grasses etc.) are much better. These not only tend to have the correct calcium:phosphorus balance, but they are also high in fibre. This latter is essential to healthy gut function. We feed our own captive-bred hatchlings exclusively on a 'wild flower' diet of hand-picked 'weeds'. The difference this makes to overall health is simply remarkable. The droppings are perfectly formed and diarrhoea is non-existent. Contrast this with the results obtained on a fruit/lettuce/tomato diet!
Things to avoid
The following items should be excluded entirely from the diets of Mediterranean species; meat; peas; beans; avocado; banana and cheese (yes, this latter has seriously been recommended as a suitable food for tortoises!).
Calcium & supplements
We use and recommend 'Nutrobal' [a general animal multivitamin and calcium supplement] as a dietary supplement for hatchlings, rapidly growing juveniles, and egg laying females. This is lightly dusted onto each meal. It ensures that adequate calcium is available at all times. It is our experience that 'Vionate', another regularly used supplement, whilst adequate for routine use with adults, is not sufficiently high in calcium to guarantee good bone development in hatchlings. [A good mammal or human multivitamin supplement may be used with an additional calcium supplement added to the food.]
An open-topped housing method is much better than an enclosed 'fish-tank' type vivarium. In fact, provided good physical protection can be attained, the sooner (Mediterranean species) hatchlings can be housed out of doors the better. Certainly, in spring, summer and on warm autumn days they will do far better outside than if confined under artificial conditions in a vivarium. Be sure to make any such enclosure not only escape proof but also predator proof - birds and rats don't treat captive tortoises any different than wild ones and regard small tortoises as a tasty morsel!. A strong covering of wire mesh will ensure adequate protection however. A natural, earthen base is best and will allow the juveniles to express their natural desire to dig and burrow. Some plant cover is also essential. Such an outside terrarium is infinitely better than even the most carefully constructed of interior vivariums. In this sort of exterior housing hatchlings will experience natural sunlight and rain; both of these provide much stimulation. Compare the behaviour patterns of juveniles housed in this way with those kept permanently indoors under artificial conditions.
©1995 The Tortoise Trust