Extinction
Wild animals were wiped out. Farm animals took their place.
6%of non-human mammal biomass is wildlife; 94% is farm animals
Farm animals now make up about 94% of the weight of all non-human mammals on Earth, while wild mammals are just 6%[2], and chicken birds, turkey birds, and other exploited birds make up about 71% of all birds by weight[1]. Wild animals were pushed out to make room for the animals we breed to eat. Around a million species now face extinction[4], and farming threatens more than 85% of the species already at risk[5]. If you cared about wildlife, you would stop eating animals.
What the evidence says
The main points first. Every claim is tied to a source below.
Our World in Data · Environmental impacts of food production
By weight, 94% of mammals other than humans are farm animals, and only 6% are wild
Weigh every mammal on Earth except humans, and about 94% of the total is cows, pigs, and other farm animals, according to Our World in Data, using figures from Bar-On, Phillips, and Milo[1][2]. Farm animals outweigh wild mammals about 15 to 1[1][2], and on land alone they make up 97%[1]. Wild mammals were pushed out to make room for them.
Read full article →71% of the weight of all birds is chicken birds, turkey birds, and other exploited birds
Weigh all the birds on Earth, and about 71% of the total is chicken birds, turkey birds, and other exploited birds[1][3], mostly chickens[3]. These farmed birds outweigh wild birds about 2.5 to 1[3], and we kill them by the tens of billions.
Read full article →A million species are at risk because we mass-breed animals we don’t have to eat
The IPBES global assessment estimates that around a million animal and plant species face extinction[1][3], many of them within decades[1]. The UN Environment Programme lists farming as a threat to more than 85% of the species already at risk[2]. We cleared their land and filled it with cows, pigs, and chickens that we mass-breed to kill.
Read full article →Wild land mammals now weigh about seven times less than they once did
Bar-On and colleagues, working from Barnosky’s older estimate, found that wild land mammals now weigh about seven times less than they did before humans hunted out the big ones[1]. The weight of sea mammals fell about fivefold after industrial hunting[1]. Total mammal weight still went up, because we replaced wild animals with animals we breed to eat[1][2], and we don’t have to mass-breed or eat any of them.
Read full article →Raising cows causes 41% of the biodiversity damage linked to farmland
According to the Oxford Martin School, cow farming accounts for 41% of the world’s biodiversity damage linked to farmland[1]. The land we’d free up by not eating farm animals is land other species need.
Read full article →Articles
Farm animals have replaced wild animals
By weight, farm animals make up about 94% of the world’s mammals other than humans, and chicken birds, turkey birds, and other exploited birds make up about 71% of all birds. Around a million species now face extinction, and farming threatens more than 85% of the species already at risk.
Read full article →
Sources
Papers and datasets. Each card keeps its caveats, including small samples and single-animal cases.
[1]PNAS, 2018 · Review
Farm animals far outweigh wild mammals, and farmed birds outweigh wild birds
Bar-On, Phillips, and Milo estimated that farm animals weigh about 0.1 gigatons of carbon (Gt C), far more than wild mammals at about 0.007 Gt C. Farmed birds, mostly chickens, weigh about 0.005 Gt C, about 2.5 times as much as wild birds (about 0.002 Gt C) and about 71% of all bird biomass. Wild land mammals now have about sevenfold less biomass than estimates for the time before humans.
[2]Our World in Data · Review
Farm animals make up 94% of the world’s non-human mammal biomass
According to Our World in Data, farm animals make up 94% of the biomass of mammals other than humans, outweighing wild mammals about 15 to 1, and 97% if you count land mammals only. Chicken birds and other exploited birds make up 71% of all bird biomass.
[3]Our World in Data · Review
Almost all mammal biomass is humans and farm animals
Working from the same global biomass census, Our World in Data finds that humans and farm animals make up about 95% of mammal biomass and wild mammals only about 5%. Chicken birds and other exploited birds outweigh wild birds.
[4]IPBES / United Nations, 2019 · Review
A million species face extinction, with farming among the biggest threats
The UN’s IPBES assessment found that around a million animal and plant species face extinction, many within decades, and that farming is among the biggest threats. More than a third of the world’s land and nearly 75% of its freshwater go to growing crops or raising farm animals.
[5]UNEP · Review
The UN says the food system is the main driver of biodiversity loss
The UN Environment Programme says the global food system is the main driver of biodiversity loss. Farming is a known threat to more than 85% of the 28,000 species at risk of extinction in its count.
[6]Nature, 2019 · Review
Nature reports farming is one of the biggest threats to Earth’s ecosystems
Nature’s news report on the IPBES assessment says up to one million species face extinction and that farming is one of the biggest threats to Earth’s ecosystems.
[7]Oxford Martin School · Review
Cow farming causes 41% of the biodiversity loss linked to farmland
Researchers at the Oxford Martin School found that farming cows for flesh and milk accounts for 41% of the world’s biodiversity loss linked to farmland.