ACCORDING to Jurassic Park, everyone's favourite fleet-footed predators dispatched their prey by disembowelling them with deadly "killing claws". Not so, say palaeontologists who have studied the biomechanics of Velociraptor claws. Instead, the notorious dinosaurs used their claws to cling to prey and to climb trees.
Phil Manning of the University of Manchester, UK, and colleagues previously showed that Velociraptor's sharp-tipped foot claw could puncture skin and help the dinosaur cling to wounded prey but was not sharp enough to rip the skin open. Now an analysis of the biomechanics of the hand claw suggests it could have supported the dinosaur's weight when it was climbing (Anatomical Record, DOI: 10.1002/ar.20986).
Manning suggests Velociraptor used its climbing ability to perch in trees and pounce on prey from above, with its claws puncturing the skin so it could cling to its victim's body while biting and subduing it. He points out that Microraptor, a tiny dinosaur in the same sickled-clawed dromeosaur family as Velociraptor but which lived some 50 million years before, had four feathered limbs to help it glide down from trees. "The leg and tail musculature show that these animals are adapted for climbing rather than running," he says.
Peter Makovicky, a palaeontologist at the Field Museum of Natural History in Chicago, says smaller ancestral dromeosaurs such as Microraptor may have been climbers, but their descendants adapted the claw for other purposes, such as latching onto prey, much as big cats with their sharp, curved claws do today.
You see the same claw shape in the dromeosaurs Utahraptor and Achillobator, both of which could grow to 6 metres long and weigh several hundred kilograms, Makovicky says. "You'd be hard put to find a tree they could climb."