日韩黄色视频网址_无码好片_激情综合激情五月_高h视频在线观看,人禽杂交无码AV,夜色福利院免费AV,2021最新国产成人精品,AV在线无码不卡,久久频这里精品99香蕉,免费高清欧美一级A片,好看的午夜色色影院

Cow might soon be the world's largest land mammal: study

Source: Xinhua| 2018-04-23 17:51:32|Editor: ZX
Video PlayerClose

NEW YORK, April 23 (Xinhua) -- Due to the spread of human activities around the world, the cow could be left as the biggest land mammal on Earth in just a few centuries, a new study has found.

The study, published in the journal Science, examines the trends of extinction of large mammals over 125,000 years.

The spread of hominims since thousands of years ago coincided with the extinction of megafauna such as the mammoth and the glyptodon, an armadillo-like creature with the size of a car, as such big animals were usually targeted by humans for meat, according to the study.

"There is a very clear pattern of size-biased extinction that follows the migration of hominims out of Africa," the study's lead author, Flisa Smith of the University of New Mexico, was quoted by the Guardian as saying.

In North America, the mean body mass of land mammals has dropped from 98 kg to 7.6 kg since the arrival of humans.

If such a trend continues, "the largest mammal on Earth in a few hundred years may well be a domestic cow at about 900 kg," the researcher concluded.h That would mean the extinction of elephants, giraffes and hippos, among others.

Despite the conservation efforts, Smith pointed out that the populations of large land mammals were falling and "declining population is the trajectory to extinction."

The world's last male northern white rhino named Sudan died in Kenya in March.

TOP STORIES
EDITOR’S CHOICE
MOST VIEWED
EXPLORE XINHUANET
010020070750000000000000011100001371312111