The Wild Mammal Biomass Has Substantially Declined

Super fact 70 : Wild mammals have declined by 85% since the rise of humans even as the total mammal biomass has nearly tripled. The result is that only 4-5% of the total biomass of mammals are wild animals. The rest are humans and livestock.

Pie chart shows that Livestock, mostly cattle and pigs, corresponds to 60% of the mammal biomass, humans are 36%, and wild mammals are 4%. | The Wild Mammal Biomass Has Substantially Declined
Livestock, mostly cattle and pigs, corresponds to 60% of the mammal biomass, humans are 36%, and wild mammals are 4%. The data is taken from this article.

As stated, mammal biomass has declined by 85% since the rise of humans. This is despite a threefold increase in mammal biomass over the last 200 years. However, this increase is almost entirely due to the growth of human and livestock populations. The result is that only 4-5% of the total biomass of mammals are wild animals. Another result is that Earth’s wild land mammals now make up just 2% of the mammal kingdom. You can read more here, or here, or here, and more in depth here.

Humans are 36% of the mammal biomass, Sheep is 4%, Livestock and pets 59%, including 2% dogs, 3% pigs, goats 3%, cattle 38%, and buffalo 6%
Humans and our livestock dominate global mammal biomass. Biomass is the total weight of each animal group. It’s calculated by multiplying an estimate of the total number of individuals by their average mass. Shown is each group’s share of global mammal biomass. This graph is taken from Our World In Data.

I think this is a super fact because we know it is true, and this huge and extremely rapid change of Earth’s fauna (from a geological timescale) is certainly important, and yet I think it comes as a surprise to many people. I often see the argument that humans have been great for animals because there are many more of them and the mammal biomass has tripled. That argument leaves out the part about the increase in mammal biomass coming from domesticated animals while wild animals have been disappearing. One question that comes to mind is whether life at the cramped factory farm is better than the life as a wild animal.

Wild Mammal Biomass Data

Below are a couple of graphs displaying some additional information on wild mammal biomass.

The graph shows that even hoofed mammals is a big group consisting of 49% of the wild mammal biomass. Rodents are 16% and elephants are 8%, bats are 7%, Marsupials are 7%, and primates are 4%, carnivores 3%, rabbits 1%, and other mammals 4%.
The distribution of the world’s wild land mammal biomass. The graph is taken from Our World in Data.

Another thing to note is that the wild animal biomass is very concentrated to just a few species. Considering that there are between 6,500 and 6,800 recognized mammal species in the world, it is quite remarkable that only 10 species make up 40% of the mammal biomass.

White-tailed deer is 12%, Wild boar is 8%, African Savanna Elephant is 6%, Eastern gray kangaroo is 2%, Mule deer is 2%, Moose is 2%, Red Deer is 2%, European roe deer is 1.8%, Red Kangaroo is 1.8%, and the Common Warthog is 1.4%.| The Wild Mammal Biomass Has Substantially Declined
Just 10 species make up around 40% of wild mammal biomass on land. The graph is taken from Our World in Data.

Reasons for Decline of Wild Animal Biomass

This decline of wild mammal biomass is primarily caused by human activity, including hunting, habitat loss and degradation from agriculture and urbanization, climate change, and pollution. This human-driven extinction event is the result of a rapidly growing human population and its increased consumption of natural resources, leading to widespread disruption of ecosystems and dramatic declines in wild mammal populations. It should be mentioned that the extinction of large mammals such as mammoths, American mastodon, giant ground sloths and glyptodonts was likely aided by human hunting in prehistoric times. The largest mammals have always been at the greatest risk for extinction and that is still true today.

A stunning AI generated illustration of a woolly mammoth standing on a snowy landscape during a vibrant sunset with northern lights in the sky.
Woolly mammoth, now extinct, Asset id: 2571557381 by Wirestock Creators.
A Glyptodon walking across an empty prairie. | The Wild Mammal Biomass Has Substantially Declined
3D illustration of a Glyptodon, also extinct, Asset id: 495169627
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Author: thomasstigwikman

My name is Thomas Wikman. I am a software/robotics engineer with a background in physics. I am currently retired. I took early retirement. I am a dog lover, and especially a Leonberger lover, a home brewer, craft beer enthusiast, I’m learning French, and I am an avid reader. I live in Dallas, Texas, but I am originally from Sweden. I am married to Claudia, and we have three children. I have two blogs. The first feature the crazy adventures of our Leonberger Le Bronco von der Löwenhöhle as well as information on Leonbergers. The second blog, superfactful, feature information and facts I think are very interesting. With this blog I would like to create a list of facts that are accepted as true among the experts of the field and yet disputed amongst the public or highly surprising. These facts are special and in lieu of a better word I call them super-facts.

46 thoughts on “The Wild Mammal Biomass Has Substantially Declined”

  2. It is startling to read the data together, as you presented. As well I was startled that deer tops the list. Since I live in a country with a lot of nature, it is easy to forget that most countries are over populated and have taken away the land from the wild animals. Maggie

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    1. Wild animals have declined but some more than others, and some wild animals have become more common such as deer. I don’t the details, but I guess it is the same as with the moose in Sweden. Predators, such as wolf has become rare and therefore there is an ovebundance of moose, and I guess an abundance of deer in most of the rest of the world.

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    1. I think that is a very common assumption. Go back a few years and I thought so to. In addition to wild animals having declined as livestock has increased, the ratio between the different wild animals has become very inbalanced. Wolves almost poff gone, deer and moose overpopulated.

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        1. Yes you are right. It has to do a lot with the way and what we feed the cattle and the industry around it. Also, there are at least one and a half billion cattle in the world. Since cows and bulls are bigger than humans they add up to a biomass that is larger than all people in the world. Considering all that it is not too surprising that cattle is responsible for about 14.5% of global human-caused emissions.

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                1. You are right Pooja. It is about moderation. The average American eat between 220-225 pounds of meat per year. Almost a pound per day, and some people are babies, small children, and vegetarians, so that is a lot per meat eater. Also a lot of food is thrown away.

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                    1. Yes you are right. We need to eat more vegetables. We especially eat a lot of red meat, such as beef, lamb, pork, (about 200 pounds per person) and red meat is the worst for the environment as well as our health.

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  6. So interesting, Thomas. I imagine that the loss of wild animal diversity will have consequences that we aren’t even aware of. It seems that humans have survived many animal extinctions over the millennia, but I wonder if there’s a breaking point where the interdependence of species collapses because one link ceases to exist. Thanks for sharing this. It’s a bit concerning, I think.

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    1. You are right, it is not just wild animals declining but there is also an imbalance. Some wild animals are more common, such as white tailed deer and moose, while other wild animals have becoming few or extinct. I’ve read that the extinction rate is 1,000 faster than normal, but that is another super fact. Thank you so much Diane.

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        1. Yes you are right. It is all connected and like the Nobel prize winning physicist Niels Bohr said “Predictions are hard especially about the future”. Not only has humans and livestock largely replaced wild mammals and wild animals in general, but the extinction rate is about 1,000 times faster than normal and we have also shifted around the balance between wild life species. There used to be 30 to 60 million bison/buffalo roaming the North American plains and now there are 8,000, with an additional close to half a million in private commerical herds (essentially turning them into cattle). But we have lots of white tailed deer and Moose in northern Europe and Canada.

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  7. seeing these figures in black and white just confirms what I already knew….however what we don’t know is the long term consequences but we can hazard a guess each animal has its place in the bigger picture having man in charge with their factory farms and meat growing laboratories doesn’t bode well for our futures …Thank you Thomas we should know the good and the bad and this is bad…

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    1. Thank you so much Carol. The point you bring up “long term consequences” I am going to post about tomorrow or the next day, the rate of extinction rate, a thousands times the normal. If it continues we will cause a sixth extinction like what happened to the Dinosaurs but this time humanity would be the asteroid.

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  10. Your scientific facts are powerful and inspiring. You present big data in a way that touches the heart and makes us stop and think. You remind us that we must care not only about numbers but also about our shared life with every creature on Earth.

    There is also something interesting about animals like wild boar and white-tailed deer. They survive well in places shaped by humans. This shows that our impact does not only destroy but also helps some species grow. Our friendly conversation can help more people understand nature better.

    The deeper message you share is clear. We are facing a big challenge, and we must act before we become the cause of a massive extinction. Your courage to speak the truth gives hope. We believe your mission to awaken global awareness will succeed.

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      1. Your message means a lot — thank you. It’s always a joy to visit your blog; the way you take complex ideas and turn them into something clear, thoughtful, and beautifully human is a gift. I learn something new every time I stop by.

        I’m grateful you received my words with such kindness. Your work reflects a lifetime of curiosity and wisdom, and it’s inspiring to walk through those reflections with you. Thank you for what you share, and for the gracious spirit behind it.

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  11. Pingback: The Extinction Rate is Much Higher Than the Natural Baseline Rate – Super Facts

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