Wildlife

24,000-year-old organisms found frozen in Siberia can still reproduce

A microscopic worm-like creature, labelled an “evolutionary scandal” by biologists for having thrived for millions of years without having sex, has now been shown to persist for at least 24,000 years in Siberian permafrost and then reproduce, researchers have found.

Multicellular invertebrates that are solely female, bdelloid rotifers are already renowned for their resistance to radiation and ability to withstand rather inhospitable environments: drying, starvation and low oxygen. They’ve also existed for at least 35m years – and can be found today in freshwater lakes, ponds, streams and moist terrestrial habitats such as moss, lichen, tree bark and soil.

These tough little critters – which have a complete digestive tract that includes a mouth and an anus – are able to survive hostile environments by halting all activity and almost entirely arresting their metabolism.

The rotifers found in the permafrost would have been under the feet of big woolly creatures – such as the woolly rhino – that are now extinct. Once thawed in a lab setting, the rotifers were able to reproduce, the researchers wrote in the journal Current Biology.

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