An astonishing new report out of the journal PLOS Genetics shows why the woolly mammoth went extinct, and how different they became in their last days. Scientists studying the DNA of these giant hairy beasts found that they were a genetic mess 4,000 years ago as they dwindled to a few hundred and eventually went extinct: they had lost their sense of smell, had a bizarre shiny coat, and they avoided social interactions with other mammoths.

It’s a major finding that could not only help us better understand how this species went extinct, but it could also provide us insight that could help us prevent the extinction of other threatened species still alive today. Scientists wanted to understand the genetic mutations of the mammoth for this study, and they found it to be a completely different animal than during its peak.

When the mammoths were on the brink of extinction, there were just a few hundred of them living on the remote Wrangel Island in the Arctic Ocean 4,000 years ago.

Researcher Rebekah Rogers said in the PLOS statement: “When I first started this project, I was excited to be working with the new woolly mammoth sequences, published by Love Dalen’s lab. It was even more exciting when we found an excess of what looked like bad mutations in the mammoth from Wrangel Island. There is a long history of theoretical work about how genomes might change in small populations. Here we got a rare chance to look at snapshots of genomes ‘before’ and ‘after’ a population decline in a single species. The results we found were consistent with this theory that had been discussed for decades.

“The mammoth genome analysis was also a great project to do with Monty Slatkin. He has spent his career developing mathematical models of how genomes will look different when population conditions change. With only two specimens to look at, these mathematical models were important to show that the differences between the two mammoths are too extreme to be explained by other factors.”