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 large amounts of fruit it will cause severe digestive tract upsets, diarrhea, 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 (Geochelone 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.