Fastest animal appendage

The fastest self-powered predatory strike by an animal's appendage is that achieved by the Dracula ant (Mystrium camillae) native to rainforests of the Indo-Australian region, which can shut its mandibles (principal outer jaws) at speeds up to 90 m/s (295 ft/s; 324 km/h; 201 mph). They achieve this high-speed movement ­– 5,000 times quicker than the blink of a human eye – with a “snap-jaw” mechanism. This involves pressing the tips of both mandibles together to build potential energy until one slides across the other – a movement akin to us snapping our fingers. Dracula ants are known to use this weapon to kill small arthropods living in the leaf litter of the forest floor, but most likely also use it for self-defence.

The research was a joint collaboration between the Smithsonian Institute, the University of Illinois, North Carolina State University and North Carolina Museum of Natural Sciences (all USA), led by with the findings published in the journal Royal Society Open Science on 12 December 2018.

Dracula ants are so-called not for their fast-moving mandibles, but for their unusual practice of feeding on the “blood” of the young in their own colonies. They consume small amounts of haemoglyph (insect “blood”) from larvae and pupae in their nests, but not enough to kill the unwitting donors.

This takes the record from a fellow ant with similarly speedy mandibles: the trap-jaw ant (Odontomachus bauri) of Central and South America, which can shut snap its outer jaws at speeds of 35-64 m/s (114-209 ft/s), as documented in 2006.