Food preference, fish attractability and behavior manifested toward new feed in young nile crocodiles, Crocodylus niloticus

Abstract

Food preference and fish-attractive parameters were studied on 1000 15- to 18-month-old Nile crocodiles, using two-choice preference tests. All three experimental groups preferred live fish over dead fish and live chicks, while ground meat was the last choice. As for fish attractiveness, motion, freshness, size, color and species were found as important parameters in the food-preference mechanism. When new feeds were presented to naive, ground-meat-eating crocodiles, we could find out the nature of innate and learned food recognition. Live fish, frogs and tadpoles were identified immediately as food, and the recognition of dead fish, chicks and anagmas required learning.