Farmer records video of rare 8-legged calf

A cow on a farm in Riau, Indonesia gave birth to a calf with four extra limbs.

In addition to its standard four legs, the calf also has three legs growing out of its back and one sprouting out next to its tail. Despite the strange-looking physical deformity, it does not seem to hinder the calf's ability to live and function normally.

The cause is likely a rare disorder called polymelia, which, based on a 2002 study, causes fewer than four in every 100,000 cows born to be born with extra limbs. The condition isn't fatal, and be found across all types of species — including humans. Typically in these cases, the extra appendages are fully formed but non-functional.

According to Dr. Laurence Denholm and veterinarian Lisa Martin, polymelia could be hereditary in cattle. Polymelia has also been linked to breaks in chromosomes or thought to be evidence of an incomplete conjoined twin.

In 2013, Dr. Jonathan E. Beever, a researcher at the University of Illinois, published a report on the recessive defect that was causing calves to be born with polymelia. Beever started investigating these cases after Australia was dealing with an increase in polymelia cases in their Angus cattle in 2011.

Thanks to Beever's findings, there is now a genetic test farmers can administer to cows to see if their unborn calves will be born affected. Although Beever also notes, the affected cows, like the one featured in the In The Know video above from Indonesia, can still thrive and live a good life.