The global biomass of mammals since 1850

Abstract

Mammals are of central interest in ecology and conservation science. Here, we estimate the trajectory of mammal biomass globally over time - including humans, domesticated and wild mammals. According to our estimates, in the 1850s, the combined biomass of wild mammals was ≈200 Mt (million tonnes), roughly equal to that of humanity and its domesticated mammals at that time. Since then, human and domesticated mammal populations have grown rapidly, reaching their current combined biomass of ≈1100 Mt. During the same period, the total biomass of wild mammals decreased by more than 2-fold. We estimate that, despite a moderate increase in the recent decades, the global biomass of wild marine mammals has declined by ≈70% since the 1850s. This provides a broader perspective to observed species extinctions, with ≈2% of marine mammal species recorded as extinct during the same period. While historical wild mammal biomass estimates rely on limited data and have various uncertainties, they provide a complementary perspective to species extinctions and other metrics in tracking the status of wildlife. This work additionally provides a quantitative view on the rapid human-induced shift in the composition of mammalian biomass over the past two centuries.

Fig. 1. Estimate of the global biomass of the class Mammalia since 1850.

Black labels indicate absolute biomass estimates, gray labels indicate the fraction of the total estimated biomass of mammals (see Fig. S9 for the estimated fraction of global biomass). Top: the total biomass of humans and domesticated mammals (cattle, buffalo, swine and others). Bottom: the total biomass of wild marine mammals, along with a coarse, preliminary estimate of the total biomass of wild land mammals, based on previously published temporal abundance estimates. For wild land mammal species with no available historical abundance estimates, the majority of species in this group, we assume that their biomass remained constant between 1850 and the present (see Discussion). To estimate the historical global biomass of marine mammals, we used a population dynamics model that relies on catch records and population estimates (following Christensen; see “Methods”). The icon for humans was created in BioRender. Greenspoon, L. (2025) https://BioRender.com/i2g5u8q.

Fig. 2. The estimated global biomass of wild marine mammals since 1850.

The International Whaling Commission declared a moratorium on commercial whaling starting in 1986, following some restrictions initiated already in the 1960s. We estimated marine mammal biomass using a population dynamics model that relies on catch data and direct population estimates, following Christensen (see “Methods”). The model inherently assumes that the only human impact on wild marine mammal abundance is direct exploitation (See “Discussion”).