Human beings have eliminated 83% of wild mammals, study finds

Published: May 25, 2018

A wood bison [Credit: pixabay]

A scientific institute has performed a sweeping survey of all life on planet Earth, and while humans make up a very small portion of all living creatures, it was found that we have had a massive impact on others.

According to a study put out in the Proceedings in the National Academy of Sciences (PNAS), humans make up 0.01% of the total mass of living things on the planet. But the study reveals that humans have had an extreme effect on other mammals, leading to the destruction of 83% of those living in the wild.

The study is the first ever to look at all of the earth’s biomass (that is, the mass of living things on the planet).

“I was shocked to find there wasn’t already a comprehensive, holistic estimate of all the different components of biomass,” the study’s co-author, Professor Ron Milo of the Weizmann Institute of Science, told the Guardian.

The study found that humans and livestock make up nearly 96% of all mammals, while wild animals make up only about 4%.  “I would hope this gives people a perspective on the very dominant role that humanity now plays on Earth,” Milo said (he himself has begun eating less meat due to the impact livestock has on the environment).

Livestock like cows now make up the majority of mammalian life on the planet. [Credit: pxhere]

Farming isn’t the only way humans impact life on the planet. Other forms of development lead to the destruction of wild habitats, which has led to what many scientists are calling a mass extinction. It is estimated that

half of the earth’s wildlife was lost in the last forty years.

In Canada alone, 521 species were listed as endangered, threatened, extirpated, or of special concern under the Species at Risk Act at the end of 2016. Some, like the North Atlantic Right Whale, of which only about 450 remain, are on the verge of extinction.  

Milo’s study did show other interesting results. For example, it revealed that there are by far more plants than any other life form on earth. 83% of life on the planet is plant life, while 13% is bacteria. Everything else — all of the creatures we tend to see and interact with in our lives — make up just 5% of organisms.

Still, when it comes to having an impact on the planet itself, there’s no contest. Humans have made the Earth what it is today.

“It is definitely striking, our disproportionate place on Earth,” said Milo. “When I do a puzzle with my daughters, there is usually an elephant next to a giraffe next to a rhino. But if I was trying to give them a more realistic sense of the world, it would be a cow next to a cow next to a cow and then a chicken.”

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