A team of scientists used observational data and complex statistical analyses, to calculate how many mammals there are in the world and, more importantly, their total mass. Among other things, this study shows that nearly half of the total biomass of wild mammals can be traced back to artiodactyl ungulates. Animals in this group include white-tailed deer, which are widely distributed in North America, and wild boar, which range from western Europe to eastern Asia, and benefit from migratory predators such as wolves.
Ron Miro and his team at the Weizmann Institute of Science in Rehovot, Israel, have collected data on the world population of 392 species of terrestrial mammals and recently published an analysis of that information in Proceedings of the National Academy of Sciences. . These 392 species for which data are available account for about 6% of all wild terrestrial mammal species. The researchers then used machine learning models to estimate global populations of mammalian species whose exact distribution is unknown. The team found that the total weight of wild land mammals is about 22 million tons. Overall, a wild sea mammal weighs twice as much as a wild land mammal. Baleen whales, such as fin whales, account for the largest share of this category, with 8 million tonnes of biomass and about 60% of aquatic mammals. Sperm whales, a species of toothed whale, also contribute a significant 7 million tonnes.
Researchers have found that the number of individual animals that make up a particular species does not indicate the species’ overall mass. Milo’s team estimates that there are 25 billion rodents in total. However, the researchers found that the biomass of these mammals, 0.5 million tons for bats and 1.1 million tons for rodents, contributed virtually nothing to the total mass number.
The team writes that biomass could serve as an indicator of global wild mammal abundance and ecological footprint. It also helps identify possible trends. Are population numbers and species diversity changing, and if so, how much are they changing?
The research team also compared that estimate to the total number and mass of all mammals on Earth. Wild mammals make up only 6% of this total. People, livestock and pets dominate the picture in every way. clever person The total weight is 390 million tons, slightly less than the 420 million tons of domesticated cattle. The dog ranks fifth with 21 million tons, but still makes up as much mass as all wild land mammals combined.
As Miró and his team write, when people observe the natural world, they are drawn to the intuitive idea that the world is vast, and that its natural diversity exceeds all human creation. These presumptions lead the researchers to want to correct this erroneous situation.
This article was originally science spectrum Reproduced with permission.
