'Thigh bone' on Mars is just another rock: NASA

A rock spotted by Curiosity rover on Mars may look like a femur bone, but it is just a weathered Martian rock formation, NASA scientists say."

A photo from NASA's Curiosity rover set the Internet abuzz this week with claims that the robot had found a "thigh bone" on the Red Planet.

NASA has dispelled the idea that the 'thigh bone' is the fossilised remains of a mysterious Martian and released Curiosity's "thigh bone" Mars rock photo with an explanation, according to 'SPACE.com'.

"Mission science team members think its shape is likely sculpted by erosion, either wind or water," NASA officials wrote in the photo description of the rock.

"If life ever existed on Mars, scientists expect that it would be small simple life forms called microbes.

"Mars likely never had enough oxygen in its atmosphere and elsewhere to support more complex organisms. Thus, large fossils are not likely," they added. Earlier this year the Opportunity rover on Mars had also found a weird rock that looked like a "jelly doughnut".

It was later explained as a piece of a larger rock that had been broken and moved by Opportunity's wheel in early January.