(ORDO NEWS) — In terms of dry weight, the largest proportion of wild mammals on land are deer, and in the sea – baleen whales.
To get accurate estimates, biologists had to generalize data from hundreds of animal species, and for thousands of less studied ones, use a neural network trained to predict their total mass.
To better understand how the biosphere of our planet works, we need exact numbers that describe its size as a whole and in parts.
How many plants and algae are there in nature? How much is for domesticated animals and how much is for humans themselves?
Such work is being done by Ron Milo of the Weizmann Institute of Israel and his colleague.
In particular, a few years ago they showed that most of the entire mass of the biosphere is land plants. In terms of pure carbon, their weight reaches 450 billion tons.
In comparison, the proportion of mammals seems quite insignificant.
Milo and his co-authors estimate that the total mass of all people on the planet (again in terms of carbon) is 60 million tons, livestock – 100 million, and together wild mammals weigh less than 70 million tons.
In the new work, scientists focused on the last point in order to calculate the distribution of biomass within a group of wild mammals.
To do this, biologists collected and processed data on the number, body weight, habitat and other key indicators of 382 animal species.
This is only a small part of the entire diversity of mammals, and to get estimates for the rest, scientists turned to the help of artificial intelligence.
By dividing the 382 most studied species into two approximately equal parts, they prepared a neural network to predict the total biomass of a species from fragmentary data.
The first part was used to train the system, the second part was used to test its predictions. This work made it possible to take into account the biomass of about 4800 more species of wild mammals.
As a result, the authors showed that the dry weight of wild mammals on land today is 22 million tons, and marine – 40 million.
Most of it – 8.8 million tons, about 40 percent – comes from a few common large species, including wild boars, elephants, kangaroos and deer.
Scientists called record holders North American white-tailed deer , the dry weight of which reaches about 10 percent of the total biomass of wild land mammals.
Despite their abundance, bats make up only about seven percent of the biomass of land animals. Rodents gain the same amount (minus rats and mice living side by side with people).
Wild predators account for only three percent of the biomass of land mammals. Among marine animals, baleen whales are in the lead, making up more than 50 percent of the mass of mammals living in the water.
—
Online:
Contact us: [email protected]
Our Standards, Terms of Use: Standard Terms And Conditions.