New Research into Arboreal Velociraptors – Sickle Claws Used as Crampons

New Study Indicates that Velociraptor Climbed Trees

A newly published scientific study, looking at the claw on the second toe of dromaeosaurs such as Velociraptor suggests that these little theropod dinosaurs were tree climbers.  In essence, Velociraptor was arboreal.

With the discovery of many more small dromaeosaurs in recent years, scientists have begun to explore the environmental niche and place in the eco-system of these agile carnivores.  In a new study conducted by researchers at the University of Manchester, animals such as Velociraptor are depicted as tree climbers.  The team suggest that the so-called “sickle-shaped killing claws” on the second pes of the hind feet were not primary weapons but were used to help these animals cling onto struggling victims.

Velociraptor was Arboreal

The paper adds weight to the theory that the claws and hind leg muscles were not strong enough to disembowel prey.

Velociraptor is classified as a member of the dromaeosaurids (the name means swift lizards).  Fossils of this dinosaur have been found in Mongolia, China and Russia.  It is thought that this animal was feathered, this would have helped insulate this active warm-blooded animal.  The curved “killing claw” was up to 9 cm long and the hands had three fingers each with an eagle like talon.

The Manchester based team, claim that the hand claws were designed to help this little dinosaur climb trees.  The long, stiff tail that made up over half the length of Velociraptor was thought to help it keep balanced as it turned sharply.  However, a stiff tail could have easily helped this turkey-sized dinosaur maintain its balance on a tree branch, much in the same way as a tightrope walker’s pole does.

A Scale Illustration of a Feathered Velociraptor

Picture credit: Everything Dinosaur

Published in the New Scientist

The report, published in the New Scientist provides evidence that the toe claws of Velociraptor were not sharp enough or strong enough to rip through the hide of typical prey animals.  The scientists led by Dr Phil Manning of Manchester University used a biomechanical model of a dromaeosaur to calculate the sort of forces the claw could generate.  The team concluded that the sharp-tipped toe claw could puncture skin and help the dinosaur to cling onto prey but it was not sharp enough along the curvature to enable the hide to be ripped open.

Studies of the jaws and dentary of Velociraptor indicate that the mouth could have been opened very wide and we have always thought it was the teeth that did the majority of the damage, perhaps by clamping down on the windpipe and causing death through suffocation or from blood loss as Velociraptors attacked this vulnerable part of many hypsilophodonts and iguanodontids.

Were Dromaeosaurids Like Velociraptor Able to Climb Trees?

The claws on the toes of some dromaeosaurids may have helped them to climb trees.  Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Examining Biomechanics

Now, an analysis of the biomechanics of the hand claw suggests it could have supported the dinosaur’s weight when it was climbing.  Dr Manning proposes that Velociraptor used its ability to climb to perch in trees and pounce onto prey animals from above.  The toe claws could act like crampons helping these dinosaurs grab onto their prey whilst the 80 or so sharp teeth in the strong jaws went about their business of subduing the poor, unsuspecting victim.

Dr Manning points out that Microraptor, a tiny dinosaur in the same sickled-clawed dromaeosaur family as Velociraptor but which lived some 50 million years before, had four feathered limbs to help it glide down from trees.

He commented:

“The leg and tail musculature show that these animals are adapted for climbing rather than running”.

The ability to climb trees may have also provided a useful escape mechanism as these smaller predators tried to avoid larger theropods.

This new paper does provide an interesting insight into the anatomical structure of the hands and feet of dromaeosaurs, after all if the majority of these dinosaurs were feathered they would not be the only feathered creatures to take to the trees, just look at the birds for example.

The Beasts of the Mesozoic range includes a variety of articulated dromaeosaurid figures.  To view this range of scale models: Beasts of the Mesozoic Models.

In commenting on the paper, Peter Makovicky, a palaeontologist at the Field Museum of Natural History (Chicago), stated that smaller ancestral dromaeosaurs such as Microraptor may have been climbers, but their descendants adapted the claw for other purposes, such as latching onto prey, much as members of the Felidae (cats) with their sharp, curved claws do today.

He stated:

“You see the same claw shape in the dromaeosaurs Utahraptor and Achillobator, both of which could grow to 6 metres long and weigh several hundred kilogrammes.  You’d be hard put to find a tree they could climb”.

If you look at modern birds, as a clade they fill a number of niches in the ecosystem.  There are large cursorial forms such as the Rhea, Ostrich and the Secretary bird as well as many other types of bird that spend much of their lives in an arboreal habitat.

Were Some Dromaeosaurs Tree Climbers?

It is certainly clear from the fossil record that there were many types of small theropod dinosaur and it is likely that this particular group of dinosaurs filled a number of places in the Dinosauria eco-system.  Certainly, if there were arboreal dromaeosaurs, forests would have been very dangerous places for small herbivorous dinosaurs.  The implications of this study on the theory of the evolution of the birds from small, bipedal theropods could also be revisited in the light of the new evidence presented in this paper.

To view a replica of the sickle-shaped claw of a Velociraptor and the other items in the extensive range of dinosaur themed toys and gifts, take a look at Everything Dinosaur’s award-winning website: Everything Dinosaur.