Thanks to sensational documentaries and summer blockbusters, we are all familiar with the anatomy of a shark attack. The victim, unaware that they are in peril, is struck from below and behind with such speed and violence that, if they are not actually killed during the first strike, they soon find themselves a few pounds lighter in the middle of a billowing red cloud of blood. The trouble is that this stereotyped scenario does not hold for all sharks, particularly one peculiar group of deepwater sharks which has long puzzled naturalists.

Thresher sharks, represented by three species within the genus Alopias, possess the classic shark body plan, but there is one feature that immediately stands out when you look at