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Scientists have brought back to lifetwo tiny worms that had been frozen for46，000 years. The worms found in the frozensoil of Siberia are the oldest living animalsever brought back to life after beingfrozen.

In 2018， scientists from Russia took adirt sample from deep in the permafrost inSiberia in Russia. Permafrost is a layer ofpermanently frozen ground that coversmuch of Siberia. The sample included frozensoil from a gopher hole about 130 feet（40 meters） below the surface. The scientistsdiscovered two tiny round worms frozenin the soil sample. The worms werenematodes （線蟲）， so small that they couldonly be seen with a microscope.

Special tests showed that the soil wasextremely old： about 46，000 years old.Even more amazingly， when the wormswere slowly thawed （解凍） out， they beganto move. They were still alive. Being revivedafter 46，000 years was a new record?for any kind of animal.

Both of the thawed worms were females.Before long， they began to have babies.The worms were sent off to Germanyto be studied further. Scientists there discoveredthat the ancient worms were a newspecies of nematode that had not yet beendiscovered. The scientists decided to namethe species Panagrolaimus kolymaensis，because they were found by the KolymaRiver in Russia.

The two original frozen nematodeshave now died. But they have lots of livingrelatives. Their babies had babies who hadbabies， and so on. There have already beenover 100 generations since the first twowere thawed. Most of the nematodes onlylive a month or two unless they get frozen.

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Why were the ancient worms named Panagrolaimus kolymaensis？

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