Bone-like object spotted on Mars by UFO watchers

UFO SIGHTINGS - One of the images sent back by the Mars rover Curiosity seems to show a human-like thighbone, partly buried in the soil.

UFO on Mars
Image Credit: NASA/JPL-Caltech/MSSS

At least that's what UFO watchers are making of it.
Indeed is seems to be a fossilized bone. The object is lying near a group of other shapes, that look somewhat like pottery.

UFO watchers have been pointing out more such objects over the last days.  Could Curiosity actually be on to something? Are we looking at the remains of lost life forms on Mars? Let's hope that research can shed light on this.