After 200 years, cows may be the largest animals of this genus.
These large mammals have held a certain fascination for us and there are many conservation efforts to protect and manage populations.
Science have always been awakening humans about the inferior count of the high sized animals, most of which have totally extinct from the Earth.
According to the study disclosed on 20 April by the journal Science in the article titled as "Body size downgrading of mammals over the late Quaternary", this kind of downsizing trend among larger mammals across the Earth is more likely to have been happened because of the major human activities and not due to the typical mammal evolution.
The massive mammals such as woolly mammoths and saber-toothed cats, roamed the Earth between 2.6 million and 12,000 years ago. The authors found a substantial bias in mammal extinction during the periods when humans were dispersing around the globe, whereby species that went extinct tended to be two to three times bigger than mammals that survived, a trend that was evident globally.
Felisa Smith of the University of New Mexico and a team of researchers set out to understand how mammal sizes have changed over time. There were the six-ton giant ground sloth in South America, Bunyanesque beavers that weighed as much as an National Football League linebacker, the 350- to 620-pound sabertooth cat in North America, the six-ton wooly mammoth in North America and Eurasia, and the two- to three-ton wooly rhino in northern Asia and Europe.
If the trend continues, it could mean that mammal body mass will drop to 4.9 kg in the next few hundred years.