We already know Mars has gravel that
was almost certainly deposited by flowing water, can critters be far
behind?
I should say that an origin of these marks by burrowing is highly unlikely. Chemically fragile crystals (such as those of evaporite minerals) are commonly dissolved and replaced by sand or other materials. This is a common process, and doesn't require organisms to produce it.
It would be astounding and wonderful to find proof that multicellular life has existed on Mars, but it is far more likely that we will find proof that minerals have been dissolved and replaced.
I should say that an origin of these marks by burrowing is highly unlikely. Chemically fragile crystals (such as those of evaporite minerals) are commonly dissolved and replaced by sand or other materials. This is a common process, and doesn't require organisms to produce it.
It would be astounding and wonderful to find proof that multicellular life has existed on Mars, but it is far more likely that we will find proof that minerals have been dissolved and replaced.
