Tadpoles avoid eating each other when alone, but overcrowding may trigger cannibalistic feeding frenzies.
Cannibalism is not all that common in nature, despite the fact that one might think that eating a member of your own species might be nutritionally beneficial - after all, a body contains all the nutrients a body needs. Dale Jefferson, a PhD candidate in Biology at the University of Saskatchewan, has been studying cannibalism in Wood-frog tadpoles, which has been observed often in nature. He was investigating what triggered cannibalistic behaviour, and he found that when raised alone, tadpoles will wait until near starvation before eating tadpole flesh. However, when other tadpoles are present, competition raises its ugly head and the tadpoles shed their reluctance. He also found that tadpoles didn't thrive on a diet of tadpole flesh, suggesting that cannibalism in the wild is a reaction to overcrowding and competition, rather than an opportunity for a good meal.