On Wrangel Island off Siberia, a small group of woolly mammoths managed to survive for some 6,000 years after the mainland mammoths died off. Though humans were a little late in discovering that—by the time we made it to the Arctic island 3,700 years ago, the beasts were on their last legs, Scientific American reports—the genes of one of that lived there 4,300 years ago is giving new insights into what may have fueled the creatures' undoing.

When compared to the genome of a mainland mammoth who lived more than 40,000 years prior, researchers found that a "mutational meltdown" had taken place among the island dwellers, one that left the beasts with a poor sense of smell and possibly diminished mating.

They also weren't so woolly by the end, with gene mutations blamed for a shiny, translucent coat, per Nature. Reporting in the journal PLOS Genetics, researchers found that gene mutations caused the island mammoths to lose olfactory receptors and urinary proteins, which in modern elephants are important for mating, per Nature.

Researcher Rebekah Rogers explains it wasn't inbreeding that did the Wrangel mammoths in, but a population so small that it messed with natural selection. "Any mammoth was better than no mammoth at all," so "bad mutations that would normally be weeded out weren’t removed from the population because of reduced competition." Paleontologist Ross MacPhee tells Nature the findings could inform modern conservation efforts: They're "maybe telling us something very important about what happens in populations already under severe threat because of diminished range and numbers." (Mammoths could be de-extinct in two years.)

This article originally appeared on Newser: Stuck on Island, Last Mammoths Had Gene 'Meltdown'