The peculiar pose of many fossilised dinosaurs, with wide-open mouth, head thrown back and recurved tail, likely resulted from the agonised death throes typical of brain damage and asphyxiation, according to two American palaeontologists.

According to Kevin Padian, professor of integrative biology and curator in the Museum of Paleontology at the University of California, Berkeley, ?virtually all articulated specimens of Archaeopteryx are in this posture, exhibiting a classic pose of head thrown back, jaws open, back and tail reflexed backward and limbs contracted?.

Dinosaurs and their relatives, as well as many early mammals, have been found exhibiting this posture.

Till now, the explanation given by palaeontologists is that they died in water and the currents drifted the bones into that position, or that rigor mortis, or drying muscles, tendons and ligaments contorted the limbs.