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The asteroid that wiped out dinosaurs 66 million years ago also killed off many mammals, according to new research.

Although the extinction of the dinosaurs is thought to have paved the way for 'placental mammals' such as humans, to dominate, the study shows that many other mammals died off alongside them.

This puts a twist on the 'classic story' that it was just the demise of the dinosaurs the allowed us to thrive - and instead suggests a mass extinction of mammals also played a part, too.

A study led by New Mexico Museum of Natural History and Science said two-thirds of our mammalian rivals went extinct with the dinosaurs (asteroid impact illustrated). So-called metatherian mammals thrived in the shadow of the dinosaurs. But many of them were wiped out by the asteroid impact

The study was led by an international team of experts on mammal evolution and mass extinctions, and was published in the journal ZooKeys.

Metatherian mammals - the extinct relatives of living marsupials such as kangaroos - thrived in the shadow of the dinosaurs during the Cretaceous period.

But, the study shows that these once widespread mammals nearly followed the dinosaurs into oblivion.

When a 6.2-mile (10km) wide asteroid struck what is now Mexico at the end of the Cretaceous period and unleashed a global cataclysm of environmental destruction, some two-thirds of all metatherians living in North America perished, according to the study.

This includes more than 90 per cent of species living in the northern Great Plains of the US, the best area in the world for preserving the latest Cretaceous mammal fossils.

In the aftermath of the mass extinction, metatherians would never recover their previous diversity, which is why marsupial mammals are rare today and largely restricted to unusual environments in Australia and South America.

Taking advantage of the metatherian demise were the placental mammals: species that give live birth to well-developed young.

They are ubiquitous around the globe today, and include everything from mice to men.

The latest findings were made when the scientists made a more detailed evolutionary tree of mammals before and after the asteroid impact - and found many metatherians went extinct alongside the dinosaurs. 

This image shows a cast of the fossil remnants of Asiatherium reshetovi, one of the metatherian species that used to live on the planet millions of years ago. Their mass extinction ultimately allowed placental mammals, from mice to man, to dominate planet Earth

Dr Steve Brusatte, of Edinburgh University's School of GeoSciences, said: 'The classic tale is that dinosaurs died out and mammals, which had been waiting in the wings for over 100 million years, then finally had their chance. But our study shows that many mammals came perilously close to extinction' (T-Rex shown)

Study lead author Dr Thomas Williamson, of the New Mexico Museum of Natural History and Science, told MailOnline: 'This is a new twist on a classic story.

'It wasn't only that dinosaurs died out, providing an opportunity for mammals to reign, but that many types of mammals, such as most metatherians, died out too - this allowed advanced placental mammals to rise to dominance.'

Dr Steve Brusatte, of Edinburgh University's School of GeoSciences, added: 'The classic tale is that dinosaurs died out and mammals, which had been waiting in the wings for over 100 million years, then finally had their chance.

'But our study shows that many mammals came perilously close to extinction.

'If a few lucky species didn't make it through, then mammals may have gone the way of the dinosaurs and we wouldn't be here.'