December 19, 2011 Leave a comment
Not Exactly Rocket Science has an interesting article on the possible hunting patterns of some dinosaurs that had claws resembling the talons of big birds of prey. They may have used their claws to pin down their prey, as opposed to hacking and slashing. The article is definitely worth reading in its entirety, so go check it out if you can, but otherwise here are the highlights:
In [paleontologist Denver Fowler’s] vision, which he calls the “ripper” model, Deinonychus killed small and medium-sized prey in a similar style to a hawk or eagle dispatching on a rabbit. Deinonychus leapt onto its target and pinned it down with its full body weight. The large sickle-shaped claws dug into its victim, gripping tightly to prevent it from escaping. Then, Deinonychus leant down and tore into it with its jaws. The killer claws were neither knives nor climbing hooks; they were more like anchors.
It’s a simple idea, but a potentially important one, for it casts Deinonychus’s entire body into a new light. Fowler thinks that it flapped its large feathered arms to keep its balance while killing a struggling victim. And its feet, which were adapted for grasping prey, would have given its descendants the right shape for perching on branches. Fowler says, “It really helps to make sense of the weird anatomy of these little carnivorous dinosaurs.” …
This idea of Deinonychus sitting on top of small prey seems at odds with classic picture of this predator working in packs to bring down larger quarry. But again, modern birds show how the same grasping motions might have worked against big targets. Golden eagles can kill reindeer. They dig their talons deep into their victim’s back, holding on while the struggling reindeer widens its own wounds. Deinonychus might have used the same strategy to kill larger prey.
Tom Holtz Jr, who studies predatory dinosaurs, says, “Prey-riding is also common in the Galapagos hawk – there’s classic footage of them taking down marine iguanas much bigger than they are. They pin them down, and flap away as the iguanas take them for a ride.” Philip Currie from the University of Alberta also mentions the famous Mongolian “fighting dinosaurs” – a Velociraptor found in pitched battle with a Protoceratops. “It confirms that dromaeosaurids were seeking prey animals of their own approximate body size.” …
If Fowler is right, his model has important implications for the evolution of flight. The dromaeosaurids would have been very nearly ready for life in the trees. Their grasping feet, with opposable toes, could easily have adapted to grip branches as well as prey. Their flapping arms, used to balance themselves, could have adapted to help them fly. These animals were positively pre-adapted for life in the trees. Perhaps the graceful wings and perching feet of a blue tit got their start with bloody murder on the ground.
Proposing such a strong connection between dinosaurs and modern birds is pretty interesting; it’s useful to see how everything is related. Keep in mind though that at this point, this is only one person’s theory.