I Know Dino Podcast: Deinonychus (Episode 14)
In our fourteenth episode of I Know Dino, we had the pleasure of speaking with Matt Martyniuk, a science teacher and paleoartist who has a prolific blog, several books, and more. Learn more about his work at mpm.panaves.com. You can also visit him on Facebook and Twitter.
The dinosaur of the day: Deinonychus, which means "Terrible Claw"
Lived in the Cretaceous about 115–108 million years ago
Paleontologist Barnum Brown technically found the first Deinonychus fossil in 1931, but he was looking for the hadrosaur Tenontosaurus and forgot about the raptor (which he had named Daptosaurus)
Grant E. Meyer and John H. Ostrom in southern Montana discovered Deinonychus in 1964, and they were the first to talk about how similar dinosaurs are to modern birds
Ostrom and Meyer found several hundred Deinonychus bones in 1964; their description of an agile predator changed people's notions about dinosaurs and made scientists speculate they were warm-blooded
Deinonychus has been found in the Antlers formation and Cloverly formation
Eight other Deinonychus fossils have been discovered in Montana, Utah and Wyoming (9 total specimens)
Deinonychus had good depth perception
Deinonychus was very bird like. It was light, fast, and walked on two legs (bipedal)
It had a flexible, curved neck, and sharp, serrated teeth
It had three fingers on each hand with large claws
It had four tows on its feet, and the second two had a sickle like claw (5 inches)
It had a large brain and was one of the most intelligent dinosaurs (measured by EQ, or brain size to body weight)
Deinonychus was 5 feet tall, 10 feet long, and weighed about 175 pounds
Compared to bigger Cretaceous theropods (T-rex, Spinosaurus), Deinonychus had a weak bite, but it was still as powerful a bite from a modern alligator
Dr. Robert Bakker wrote in his book The Dinosaur Heresies (1986) that Deinonychus had many similarties to birds
Dr. Philip Currie has recent research that dinosaurs similar to Deinonychus (Velociraptor, Utahraptor, Dromaeosaurus) probably had feathers covering all or at least part of their bodies (proto-feathers used for insulation and/or display)
Could probably run at 6 mph, not as fast as other theropods
The Velociraptors in Jurassic Park were actually Deinonychus
Velociraptor would come up to a bit above the knee on an adult average man while Deinonychus would reach a man's chest
Deinonychus was one of the first raptors discovered from an almost complete skeleton. Scientists had found Velociraptor 40 years earlier, but only named it based on a skull and some parts of its hands and feet
This new idea that dinosaurs were agile partly inspired Gregory S. Paul, a paleo-artist, to create his 1988 book Predatory Dinosaurs of the World. He grouped Deinonychus fossils as Velociraptors, since the two had so many similarities (and Velociraptor was named first)
Paleontologists still think the two dinosaurs are different, but the book was very popular. Michael Crichton read the book (acknowledged it in the Jurassic Park novel) and he described Deinonychus in the book as Velociraptor (stayed that way in the films)
Larger Deinonychus's could probably bite through bone
It used its tail to counterbalance when running and pivoting, which would have helped catch up to prey
Deinonychus fossils have been found near Tenontosaurus fossils, which makes some scientists think Deinonychus hunted in packs
Deinonychus may have hunted sauropods and ankylosaurids (in packs)
Tenontosaurus adults weighed two tons, which means the only way Deinonychus could have hunted it was in packs
Deinonychus may have used its arms to hold onto prey and tear off chunks with its teeth
Studying Deinonychus has given a lot of insight into how raptors behaved
The tail had a rigid "pole" that only moved at the base (tendons at the tail overlapped several vertebrae)
Deinonychus used its claw on the second toe of each foot to stab prey (Velociraptors used their claws for slashing)
Deinonychus may have used the claw to hit the neck, or used as defense against other dinosaur species or against other Deinonychus when defending its territory or trying to dominate the pack
The claw was held back and did not touch the ground when Deinonychus was walking (means it did have a specific purpose). Instead, it rotated the claw upwards and ran on its other toes
Deinonychus may have stabbed its prey and waited for it to bleed to death from a safe distance
Ostrom compared Deinonychus to an ostrich or cassowary
Can see Deinonychus at the American Museum of Natural History and the Harvard Museum of Comparative Zoology, though they are from different areas and have different shaped claws (may be two different species or genera)
Deinonychus is part of the Dromaeosaur family; though no Deinonychus fossil feathers have been found, Dromaeosaurs are known for having feathers
Their family name means "running lizards" and they are often referred to as raptors (they have very bird like habits)
They also had great vision and large brains and lived in the Cretaceous
Dromaeosaurs had a great sense of small, like tyrannosaurids and turkey vultures
They were mostly small to medium sized and they were bipedal
They had long tails, many with rod-like extensions. Tails were flexible at the base, probably used as a counterweight or to help stabilize while running
Dromausaurs may have been most closely related to birds
They had feathers. Some feathers were long, some were shorter and more down-like. The feather patterns were very similar to Archaeopteryx
Scientists think at least two dromaeosaurs could have flown or at least glided (Rahonavis ostromi and Microraptor gui)
Dromaeosaurs had light skulls, sharp backward curved teeth, long arms and hands with claws, and sickle-like second toe claws that never touched the ground in order to keep it sharp
May have used their sickle like claw to climb trees or large prey (as well as for stabbing)
Phillip Manning and a team tested the function of the sickle claw in 2009 by using X-ray imaging
The team compared how the sickle claw curved with the foot curvature of modern birds and mammals (curvature gives insight into an animals lifestyle; strongly curved means the animal climbs, but less curved means the animal spends most time on the ground)
Deinonychus has a 160 degree curvature, good for climbing
Still, some later, larger dinosaurs with very curved claws would have been too large to climb trees, so may have used it to latch on to prey instead
Phil Senter said in 2009 that dromaeosaur toes may have been able to get through tough insect nests, so some smaller dromaeosaurs (Rahonavis and Buitreraptor) may have eaten insects as part of their diet, and larger ones such as Deinonychus may have caught small prey in insect nests (though he did not test whether the claws could actually do those things)
Denver Fowler and his team in 2011 said dromaeosaurs may have used "raptor prey restraint" or RPR on smaller prey, by jumping on the prey, pinning it, and gripping it with its claws, taking bites while the prey was still alive (prey eventually bleeds out and organs fail)
Fun fact: Most baby dinosaurs had proportionally larger eyes and smaller faces than adults, which made them just as cute as other baby animals
For those who may prefer reading, see below for the full transcript of our interview with Matt Martyniuk:Continue Reading …
Filed Under: Dino Podcast, Interviews Tagged With: Deinonychus, dinosaur, dinosaurs, dromaeosaurs, i know dino podcast, jurassic park, Matt Martyniuk, paleoartist, terrible claw, velociraptor