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Fowler et al. 2011b -extra images
FOWLER, D.W., FREEDMAN, E.A., SCANNELLA, J.B., & KAMBIC, R.E. (2011) The predatory ecology of Deinonychus and the origin of flapping in birds. PLoS One 6(12): e28964. doi:10.1371/journal.pone.0028964

This page contains numerous images available for press / blog use.

There are additional notes and comments on the research here: (Fowler et al., 2011b).

This image shows a dromaeosaurid dinosaur standing atop its prey, using the enlarged sickle claw of the foot to maintain its position.

Research conducted at the Horner paleo lab, Museum of the Rockies, Montana State University.

Original art by Nate Carroll; arrangement by D. Fowler.

For all images, click on the image for a large version

The same image is available without text.

Original art by Nate Carroll.

This picture shows a small dromaeosaur in side view. The forelimbs are wrapped around the prey (mantling) preventing its escape. The predator's head reaches down between the feet to dispatch its victim.

Original art by Nate Carroll.

Foot proportions vary depending on what a dinosaur is doing with its feet.

the photo shows a Daspletosaurus foot (left), and a Brachylophosaurus foot (right). These specimens are currently on display at the Museum of the Rockies.

Daspletosaurus is a carnivorous tyrannosaurid dinosaur: closely related to Tyrannosaurus rex.

Brachylophosaurus is a plant-eating duckbilled dinosaur.

Photo by D. Fowler.

This image is taken directly from the original paper (Fowler et al., 2011b). It shows how different proportions of the feet indicate different uses.

Dinosaurs that are adapted for running or walking have a foot that is proportioned like a modern Emu, with a large middle toe, and side toes that are shorter and about equal in length (e.g. Gallimimus,A; and Allosaurus, B). Deinonychus (C) is very different, with an unusually long outer toe (D-4), and very short inner toe (D-2); proportions more suited to grasping.

Image by D. Fowler.

This photo shows a right foot of a Deinonychus (MOR 747) currently on display at the Museum or the Rockies, Bozeman, Montana. The specimen was collected in 1993.

The foot is in walking pose, with the enlarged D-II claw held above the ground.

This was one of the principal specimens used for the study. It was especially useful as it is preserved in 3D, and can therefore be set into different poses, to study the range of movement at the different joints.

The MOR dig recovered two other Deinonychus feet from the same locality. These were also fairly complete, and used in the new study.

Photo by D. Fowler.

These photos show a cast of the same foot of Deinonychus, but this time arranged in flexion: grasping. You can see how the enlarged claw on the inside toe (digit-2) moves in parallel with the middle toe (digit-3), while the outer toe (digit-4) can reach over the 'palm' of the foot, partially opposing the smallest toe (digit-1)

The photo on the left is taken directly from the original paper, whereas the photo below is an early rough version taken during the analysis.

Photos by D. Fowler.

This is the complete behavioral model for the predatory behavior of dromaeosaurids. Image taken directly from the original paper.

RPR (Raptor Prey Restraint) “ripper” behavioural model, illustrated by a small dromaeosaurid

(A) grasping foot holds on to prey. (B) hypertrophied D-II claw used as anchor to maintain grip on large prey. (C) predator's bodyweight pins down victim. (D) beam-like tail aids balance. (E) low-carried metatarsus helps restrain victim. (F) “stability flapping” used to maintain position on top of prey. (G) arms encircle prey (“mantling”), restricting escape route. (H) head reaches down between feet, tearing off strips of flesh (may explain unusual deinonychosaurian dental morphology). Victim is eaten alive or dies of organ failure.

Detailed drawings by Nate Carroll; line art by Lee Hall; arrangement by D. Fowler.


This image is from Fowler et al. (2009)

The dinosaur research stems from a paper published in 2009 by the same authors. This paper looked at variation in foot proportions among modern birds of prey, paying special attention to how this variation affected strategies for catching and killing prey.

Note the digit length and relative enlargement and curvature of claws within each foot: Accipitridae (hawks and eagles; A, B) bear hypertrophied talons on D-I and II; Falconidae (C) have only modest talons on each digit and only slightly enlarged D-I and II; Strigiformes (owls; D) bear large talons with comparatively low curvature on each digit; Pandionidae (Osprey; E) have enlarged, highly recurved talons on each digit.

(A) goshawk, Accipiter gentilis. (B) red-tailed hawk, Buteo jamaicensis. (C) peregrine falcon, Falco peregrinus. (D) great grey owl, Strix nebulosa. (E) osprey, Pandion haliaetus.

Image/photos by D. Fowler

Our team's research on claws has broadened to include more than just carnivorous dinosaurs, highlighting how little research has been conducted on claws and their uses.

Another of our papers published earlier this year (Fowler & Hall, 2011) showed that the shovel-shaped claws on the hindfeet of sauropods (long-necked plant eaters, e.g. Diplodocus) were adapted for scratch-digging. This is thought to have been of use when sauropods were digging out their nests, into which they laid their eggs.

This photo shows a reconstructon of a Diplodocus hindfoot, illustrating the spade-like shape of the claws.

Image is taken directly from Fowler & Hall (2011).

Photo by D. Fowler.