Almost all of the world’s mammal biomass is humans and livestock

A diverse range of mammals once roamed the planet. This changed dramatically with the arrival of humans, who have become the dominant species through our own populations, as well as the animals we breed and raise for food.

There are various ways to compare the distribution or abundance of different types of mammals. One way is to compare them based on the number of individuals. In these terms, very small animals vastly outnumber larger animals, but this doesn’t necessarily give us an idea of how much ecological and biological resources different animals use.

Another metric that ecologists often use is biomass — the total weight of all animals of a given species. This not only takes into account the number of animals but also factors in their size.1 It gives more weight to larger animals at higher levels of the ecological “pyramid”: these rely on well-functioning bases below them.

Let’s then look at the breakdown of the global mammal kingdom in these terms.2 It’s shown in the chart below. This data is sourced from the study by Lior Greenspoon and colleagues.3

Each square represents one percent of the world’s mammal biomass, including both land and marine animals. For context, that 1% is equal to around 11 million tonnes......