Hesperonychus was a tiny, chicken-sized, dromaeosaurid dinosaur.
Hesperonychus lived in the swamps and forests of Late Cretaceous North America.
Hesperonychus used its rows of serrated, dagger-like teeth to feed on insects.
Hesperonychus might have had an excellent sense of smell, like its close relative Velociraptor.
Elizabeth Nicholls discovered the first Hesperonychus fossil, a well-preserved pelvis from the Dinosaur Park Formation in Alberta, in 1982. Nicholls died in 2004 and the fossil remained unstudied until it was relocated in a museum drawer and described by Longrich and Currie in 2007. The bone was first thought to be from a juvenile, until it was realised the pelvis was fused and must have come from the adult of a very small dinosaur.
Height: 0.5m (1.64ft)
Length: 0.9m (2.95ft)
Weight: 1.81kg (4lbs)
Top speed: 39.0kph (18.64mph)
Vision: Being a dromaeosaurid, it is likely that Hesperonychus had excellent eyesight, probably similar to that of modern birds.
Skin: Hesperonychus almost certainly had feathers. Those of its relative, Microraptor, were iridescent – probably for displaying to potential mates. It is possible Hesperonychus had feathers like this too.
Brain: Dromaeosaurids were among the most intelligent of dinosaurs and it is likely that Hesperonychus would have been among the most intelligent of this group.
Prey: Hesperonychus probably hunted insects, mammals, amphibians and maybe even baby dinosaurs.
Bite: Philip Currie describes Hesperonychus as 'one of those nasty little raptors, like a Velociraptor, with the same kind of claws and same kind of teeth. Only much, much smaller.'
Nest: Hesperonychus probably laid eggs in a nest, which the mother would tend, like birds do today.