An international research team has reported that roundworm species found in permafrost in Siberia are older than previously thought.

The team revived the worms and determined they had been in a state of suspended animation for a record-breaking 46,000 years. The finding could shed light on how animals adapt as habitats shift due to environmental changes.

The team of researchers from Russia, Germany and elsewhere published its findings in the online US science journal PLOS Genetics on Thursday.

The researchers said the nematodes began moving after they were thawed out in a lab.

They discovered that the worms had been in a dormant state known as "cryptobiosis" for about 46,000 years.

Some organisms, such as tardigrades, are known to survive harsh conditions, including being dried out or frozen, by entering a prolonged dormant state.

The researchers said the nematodes may have set a new record for length of survival in a dormant state for any animal.

They said the worms reproduced and now number in the thousands.