Humans destroyed 83% of all wild mammals, study finds

Imagine all the animals on Earth: Lions and giraffes, monkeys, penguins and bears. All those exist, sure, but you're far more likely to come across cows, chickens, cows and more cows. 

That's how Ron Milo, a biologist at Israel's Weizmann Institute of Science, broke down a new globe-spanning study for The work, a census of life on Earth, found 83% of all wild mammals have vanished amid the rise of human civilization.

With more humans came demand for more livestock — think farmed pigs and cattle — which now makes up 60% of all mammals, as measured by biomass, the study found. And farmed poultry now makes up 70% of all birds on Earth.

Just 4% of all mammals today live in the wild.

The study, which highlights humanity's "radical ecological effects," published this week in the Proceedings of the National Academy of Sciences.

While humanity boomed over a short time through farming, livestock and the Industrial Revolution, authors note, humans now make up a relatively measly 0.01% of all life.

But that speck of humanity has an outsized impact: Intense whaling helped decimate 80% of all marine animals, and half of all plants on Earth have been lost.

“I would hope people would take this (work) as part of their world view of how they consume,” Milo, an author on the study, told The Guardian. He now eats less meat, he said.

Researchers pulled from hundreds of studies for the first-of-its-kind analysis, per the newspaper, using data from satellite scans and gene sequencing to calculate the biomass on Earth.