>>50010110Sexual dimorphism doesn't necessarily prevent animals from transitioning. In clown fish, for example, a colony is made up of one massive female and a bunch of horny little males. When the female dies, the biggest male plumps up and becomes the new female. Guppies, on the other hand, won't develop functional genitalia when they undergo these changes, but they will take on all of the other physical traits of the opposite sex when the male to female ratio becomes unbalanced. I only really know about fish, but there are plenty of examples of land-dwelling critters that have evolved the same way.
