On this planet there are two species of alien humanoids creatures , one group evolved an omnivore based diet and the other has a semen based diet, both groups are bipedal and share a common ancestor.
I'm trying to figure out what type of evolutionary factors and genetic changes could have lead this group of humanoid creatures on this planet to evolve a diet based out of semen. I'm using the vampire bat as an example of creatures that have switched from a solid to a fluid based diet.
one of the obstacles for vampire bats was developing a digestive system that allowed them to excrete large amounts of metals such as iron. Could the same be applied to these humanoid creatures?
what type of biological changes needs to happen for a semen based diet?
How much semifinal fluid would these aliens need to survive?
How will they manage to survive with this diet?
since their primary source of food is fluid based , how would it effect their jaw and teeth?