Study predicts cows may soon be the biggest land mammal left, and another mammal is to blame – us
In North America, the average size of land mammals has shrunk from 98kg to 7.6kg since humans arrived
The spread of humans around the world from Africa thousands of years ago wiped out big mammals in a shrinking trend that could make the cow the biggest land mammal on Earth in a few centuries’ time, a scientific study said on Thursday.
The spread of hominims – early humans and relatives such as Neanderthals – from Africa coincided with the extinction of mammals such as the mammoths, sabre-toothed tiger and glyptodon, an armadillo-like creature the size of a car.
![It may only be a few hundred years before domestic cattle like these Herefords in Canada are the biggest mammals left on Earth. Photo: Corbi]](https://img.i-scmp.com/cdn-cgi/image/fit=contain,width=1024,format=auto/sites/default/files/images/methode/2018/04/20/24b7efca-444f-11e8-ab09-36e8e67fb996_1320x770_121318.JPG "It may only be a few hundred years before domestic cattle like these Herefords in Canada are the biggest mammals left on Earth. Photo: Corbi]")
Humans apparently targeted big species for meat, while smaller creatures such as rodents escaped, according the report examining trends over 125,000 years.
In North America, for instance, the average body mass of land-based mammals has shrunk from 98kg to 7.6kg since humans arrived.
If the trend continues “the largest mammal on Earth in a few hundred years may well be a domestic cow at about 900kg” the US team wrote.