Has an alien 'thigh bone' been spotted on Mars?

Curiosity rover took a photo on August 14, which led conspiracy theorists believe that it was a 'bone-like' object on Mars.

NASA's scientists said seen by Mars rover Curiosity using its MastCam, this Mars rock might look like a femur thigh bone, however, mission science team members think its shape was likely sculpted by erosion, either wind or water and if life ever existed on Mars, scientists expect that it would be small simple life forms called microbes, Stuff.co.nz reported.

Mars likely never had enough oxygen in its atmosphere and elsewhere to support more complex organisms, therefore, large fossils are not likely to exist, they further added.