Extinction of glacial megafauna linked to small brain size

(ORDO NEWS) — Israeli and European paleontologists have found that the end of the ice age led to the extinction of mainly those mammals that had relatively small brains compared to their total body mass.

This potentially explains the disappearance of almost all representatives of the glacial megafauna, scientists write in an article in the journal Scientific Reports.

“We studied the brain sizes of about three hundred living and five dozen extinct species of mammals that disappeared at the end of the glaciation.

Our calculations showed that the relative brain sizes in the first group of mammals were about 53% larger than in extinct animals, which indicates important role of this feature of mammalian anatomy in the extinction of glacial fauna,” the researchers write.

The last ice age in Earth‘s history began about 2.6 million years ago. Its main characteristic feature – the area of ​​glaciation and the temperature of the Earth’s surface throughout its length were not constant.

Glaciers advanced and retreated every few tens of thousands of years as a result of sharp cooling and warming. The last “thaw” of this kind began about 13 thousand years ago and continues to this day.

The end of the ice age was accompanied by the extinction of a large number of plants and animals, including mammoths, woolly rhinoceroses and giant sloths, which had previously experienced numerous retreats and advances of glaciers.

Scientists have long been trying to understand why these representatives of flora and fauna disappeared, as well as what role humans could have played in their disappearance.

Reasons for the extinction of megafauna

A group of paleontologists led by Professor Shai Meiri of Tel Aviv University (Israel) became interested in how the relative brain size of mammals could affect the likelihood of extinction of certain representatives of the megafauna.

Scientists have suggested that the large brain helped animals quickly adapt to changing environmental conditions, including avoiding contact with humans.

Based on similar considerations, scientists have calculated the brain volume of about three hundred species of mammals that inhabit all the continents of the Earth today, as well as five dozen species of megafauna and other mammals that became extinct at the end of the ice age.

Paleontologists compared these data with the size of the body of animals, after which they compared the relative sizes of the brain of extinct and living mammals.

Their calculations showed that the probability of extinction of all living creatures studied could be very accurately determined by how large their brains were.

On average, all mammals that exist today have 53% larger brains than mammoths, woolly rhinos, saber-toothed cats and other megafauna that disappeared 15-10 thousand years ago.

The existence of this pattern, according to Professor Meiry and his colleagues, suggests that behavioral flexibility and the ability to quickly adapt to new environmental conditions played a key role in the survival of animals after the end of the ice age.

Subsequent studies and calculations will show what place man occupied in these evolutionary processes, the scientists concluded.

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