A bird-like dinosaur that prowled an ancient forest 125 million years ago used venom to subdue its prey, according to a new theory.

Sinornithosaurus‘s upper teeth resemble those of “rear-fanged” snakes which bite their prey and channel venom into the wound.The dinosaur probably fed on the abundant birds which inhabited what is now north-east China.The work appears in Proceedings of the National Academy of Sciences journal.

Rear-fanged snakes are considered less dangerous than other venomous snakes.The fangs in these snakes do not inject venom, but instead channel the poison along a groove on the outer surface of teeth that pierce their prey’s flesh.

Skull of Sinornithosaurus

Sinornithosaurus had upper teeth that were similarly long, grooved and fang-like.

David Burnham, from the University of Kansas, US, and colleagues, say the dinosaur’s upper jaw also contained a pocket that could have housed a venom gland. This is connected to the base of the teeth by a long groove.Like rear-fanged snakes, the venom Sinornithosaurus used was probably not lethal. The researchers suggest it instead caused rapid shock, allowing the dinosaur to subdue its prey.