The Ice Age has already ended about 12,000 years ago, and with it, several giant animals also began to disappear. In part, due to climate change and hunters’ increasing demand for these animals, El País said.
These giants, the mammoths, were among the largest herbivorous animals in North America and Siberia, however, about ten thousand years ago, they began to disappear from the mainland, and then lived on isolated islands.
There are already about 3,700 years ago, that the mammoths were extinguished, at which time Man began to build the first temples. Recently, an analysis published in PLOS Genetics, by researchers Rebekah Rogers and Montgomery Slatkin, both from the University of California, helped to conclude that although mammoths were able to live many centuries in those isolated areas of the planet, they were already destined to disappear from the map.
In order to complete this study, we analyzed two mammoths that lived in very different times, one of them lived about 45 thousand years ago, and died in Siberia. There was then a population of about 13,000 mammoths. The second mammoth, died about 4,000 years ago, in isolated territory in the Arctic. At that time, the estimated mammoth population was about three hundred. All the analyzes made, detected deformities in the animals’ DNA, deformities that already foresaw their extinction, even before the true extinction occurred.
Over the years, animals that already had a set of mutations in their genome, which in turn were interfering with their genes, caused them to lose their olfactory receptors and some proteins in their urine (which in similar species would interfere with the ability to choose a partner). In addition to these, other changes that have been verified are related to the hair, which previously protected them from the cold, but which would eventually have been replaced by a thinner and less effective layer against the temperature and surrounding environment.
Those responsible for this study also advanced that the results obtained are also very important for the conservation movement, a movement that believes that isolating a small group of animals can protect all of its species.
Conversely, this study also suggests that when a population falls below a certain
threshold, isolating the group will not cause changes in the genome to be avoided.
David Bravo, a professor at the Natural History Museum in Denmark, told El Pais that this accumulation of “defects” in the genomes of animals is reflected in how they can or cannot respond to abrupt, for example, climatic changes.
“We know that with the warming of the planet, the amount of fresh water on the islands where these mammoths lived has greatly diminished. These changes affected more individuals than others, particularly those who were weaker and did not have genetic diversity to help them respond better to these changes”, he explained.
According to Bravo, these data also indicate that existing plans for recovering extinct species, or even saving some from extinction, may be a mistake.