Adaptation

Crocodilians routinely feed on fish and other small animals which do not require dismemberment before being consumed. However, when encountering prey larger than what can be swallowed whole, crocodilians are faced with a very big problem; their teeth are not adapted to cut or slice. Crocodilian teeth are sharply pointed but conical, having no side edge or serration. This of course makes it impossible for crocodilians to bite off smaller pieces of flesh to swallow

The tooth on the left is from a common crocodile while the tooth on the right is from a Carcharodon carcharias, a type of shark. The conical un-edged shape of the crocodilian tooth is especially evident when compared to the tooth of the shark, which has sharp serrated edges for cutting. Images credit phatfossils.com

Despite this handicap, crocodilians do still consume game larger that what can be swallowed whole, by removing pieces of flesh of a more manageable size. And they accomplish this through the death roll adaptation. The death roll enables crocodilians to remove pieces of flesh by rapidly twisting, forces their teeth sideways through the flesh and thus slices pieces off (1). Although there are instances of crocodilians executing a death roll on land, it is a behavior especially well adapted to a water environment, in which the specific dynamics of the roll produce relatively little drag on the crocodilians body, and the water suspends the animal during the behavior, leading to relatively low energy expenditures (1). This adaptation can also be seen in a species of subterranean amphibian that also has extremely small conical teeth, providing an interesting example of a homoplasic adaptation (2)