Ancient owl with ‘murder feet’ unearthed
A55-million-year-old owl fossil with so-called ‘murder feet’ has recently been described. Based on its preserved foot bones, this ancient avian predator likely hunted like a hawk, killing its prey with piercing talons, unlike its modern-day relatives that use their beaks to kill. The newfound skeleton, which represents a previously unknown owl genus and species, is the oldest near-complete owl fossil.
Though the fossil is missing its skull, nearly all the other bones in its body are intact and preserved in three dimensions. And this owl was a big one; at nearly 60 centimetres long it would have been about the size of a modern snowy owl (Nyctea scandiaca).
The fossil was discovered in 1990 in the Willwood Formation in northern Wyoming, in sediments deposited about 55 million years ago. Researchers named the newly described owl Primoptynx poliotauros, Primoptynx meaning ‘first owl’ in Latin.
Palaeontologists identify ancient owls by looking at the shapes of certain bones, among them the shoulder bone, the humerus in the wings and leg bones such as the tibiotarsus – a bone between the knee and the heel – and the tarsometatarsus – the bone between the heel and the toes – which are important for catching prey or perching. In the case of Primoptynx, however, the bones that captured the scientists’ attention were in the owl’s toes. The toes of modern owls are all about the same size. Primoptynx’s first and second toes were bigger than the others, so its feet most closely resemble those of predatory raptors such as hawks and eagles. This suggests that the extinct owl hunted as hawks do, targeting larger or more difficult-tocapture prey and then clutching and piercing their bodies in a lethal death grip with its feet. By comparison, owls typically stab prey to death with their sharp beaks.
When Primoptynx soared across Wyoming skies 55 million years ago, North America was populated by mammals such as primates, rodents and early relatives of deer and horses. The owl’s impressive feet could likely grip something the size of a rabbit, but rabbits had yet to appear in the region. Prior to this discovery, the oldest owl fossils were bone fragments and a leg bone dating to around 60 million years ago.