Scientists reveal humans are descended from a shrew

A painstaking study to trace the earliest mammal ancestor of human beings has resulted in the naming of the shrew.

Artist's impression of the earliest ancestor of most mammals living today, including humans Credit: Carnegie Museum of Natural History

Scientists believe the insect-eating creature evolved some 200,000 years after a massive asteroid impact led to the extinction of the dinosaurs.

The shrew-like animal is the first example of a "placental" mammal - the largest branch of the mammalian family tree which includes dogs, cats, rodents, whales and humans.

Experts in the US recorded 4,500 physical traits for 86 mammalian species, including 40 that are now extinct, in order to build up a picture of how the creature would have looked.