Did mammal beat birds to skies?

MAMMALS may have experimented with flight at the same time as the first birds, or even earlier, a new fossil discovery suggests.

A small, squirrel-like creature that lived in China 125 million years ago possessed a skin membrane that may have allowed it to glide from tree to tree, researchers have found.

The animal resembled modern flying squirrels, which are also adapted for gliding flight, but was a carnivore that fed on insects.

The discovery of the skeleton — which is as old as the earliest bird fossils — pushes back the first record of mammals with an ability to glide by at least 70 million years. By comparison, bats are unknown before around 51 million years ago.

The discovery shows how varied early mammals were in their lifestyles and locomotion strategies, according to the team of scientists — led by Dr Jim Meng, from the American Museum of Natural History in New York — which conducted the research.

They wrote in the journal Nature: “[Mammals] had experimented with an aerial habit at about the same time as, if not earlier than, when birds endeavoured to exploit the sky.”

The squashed skeleton of the animal, named Volaticotherium antiquus (ancient flying beast), was found at a site located in Daohugou, Ningcheng County, Inner Mongolia.

Analysis of the fossil revealed specialised insectivorous teeth and a sizeable patagium, or flying membrane supported by an elongated tail and limbs.

The scientists said the creature would have been an “agile glider” because of its small body mass and large patagium, but probably could not capture airborne insects, as bats do.

“Gliding is thought to be ancestral to bats and arose up to seven times independently within three other mammalian groups,” according to the researchers.

“Gliding... has its advantages, such as being energetically economic, allowing a wider foraging area, and enabling evasion from predators in arboreal environments, but fossils of gliding mammals are extremely rare.”