The team placed electrodes on the skin of a dozen birds from 10 different species, ranging from chickens to bald eagles. This allowed them to identify the precise muscle movements that underlie each stage of feeding. The team was particularly interested in the avian muscle M. complexus, which is used for head dorsiflexion (upwards flex) and lateroflexion (to the side).
They found that the birds raised their heads and fixed their gaze on their prey before lowering their heads to attack. Since T. rex had many of the same muscles, the work suggests how the dinosaur could perform the same movements: raising its head and thrusting it upwards. The muscle also helped stabilize the head as T. rex tore flesh by rearing back its body through the extension of its legs.
Additionally, many of the birds also shook their necks — like a dog shaking off water. Snively thinks that the dinosaur used this motion to dislodge meat from a carcass. According to one reconstruction, the tyrannosaurid neck muscles combined the functional regionalization seen in birds, with the robustness of crocodilian musculature. “We can think of them as striking like a bird, and shake-feeding like a crocodile,” Snively tells New Scientist
Well that explains it. “Tyrannosaurs didn’t need big arms to hunt, because their powerful bites and hyper-bulldog necks did the job,” Snively explains
. “From the shoulders forward, T. rex
was like a whole killer whale: just bite, shake and twist.” So many wonderful animal metaphors.
was published in Journal of Zoology
Image: J. Fang
Wonder Of Science