The velociraptors of Jurassic Park struck fear into cinema-goers with their vicious cunning, while the Tyrannosaurus Rex's brute strength and magnificent teeth made it the deadliest carnivore in the prehistoric jungle. However, mainland scientists believe they have found a rival: a dinosaur that produced venom. Professor Gong Enpu, a palaeontologist from Northeastern University in Liaoning, led a team that examined the fossil of a small dinosaur called Sinornithosaurus, or the Chinese bird-lizard, which was found in the Liaoning village of Sihetun 10 years ago. They discovered a few long, backward-pointing fangs that contained grooves - a delivery system for poison. The discovery would help answer some of the most intriguing questions about dinosaurs, such as how they hunted and killed, Gong said. The behaviour of some modern venomous species such as snakes can now be used as a guide to the species that became extinct 65 million years ago. When it was unearthed, Sinornithosaurus caused quite a sensation in the pathological community because it was one of the first bird-like dinosaur fossils to be found. Researchers spent a lot of time arguing about whether they were birds or dinosaurs, or, if they were dinosaurs, which family they belonged to. To answer these questions they carefully examined every bone and feather. But few took a serious look at the teeth. Few scientists suspected that dinosaurs used venom on their prey because it seemed unnecessary and there was no poison to be found after 100 million years. Gong said his team discovered the grooves by accident, and when they compared their features to the grooves of venomous raptors in South America, they were stunned. 'Most peers who reviewed our paper gave positive comments. The evidence is quite obvious,' he said. The paper will be released in the forthcoming issue of the US National Academy of Sciences' journal. By comparing the venomous system of the Sinornithosaurus to, say, that of a snake in the Amazon rainforest, scientists can picture how the most deadly weapon in the animal kingdom evolved through millions of years. 'The venomous teeth of modern snakes are undoubtedly more powerful. Once they bite into a prey, the strong [teeth] structure allows it to generate high pressure and inject the venom into the victim's flesh and blood. The prey will be killed quickly, if not instantly,' Gong said. 'But the Sinornithosaurus' teeth are more primitive. Instead of an injection, their poison delivery was more like a trickle. We suspect that the toxicity of their poison was not deadly, either. They would paralyse their prey and then drag it to a safe spot to begin the feast.'