Seuxal dimorphism in fiction.
A.k.a. Sexual Dimorphism. No Real Life examples please ... in fact, let's not do any examples period. Just need help with the description in general, and which title should be the one to use.
Secondary Sexual Characteristics, or Sexual Dimorphism, are elements of a creature's physiology that result from it being male or female. It is one step removed from "primary sexual characteristics" (which describes the actual reproductive organs, and we don't talk about that). For example, everyone knows that only male lions have that iconic mane of fur around their neck; it is one of their specie's Secondary Sexual Characteristics. Many times, fictional creatures are based on some manner of Real Life inspiration, and whether or not they have noticeable sexual dimorphism corresponds to whatever inspiration they came from -- if one author decides to call a lion a Smeerp, it makes sense that male Smeerps might have thick manes while female Smeerps do not, right? Now a full discussion of these characteristics is well beyond the scope of this wiki; but when dealing with this subject in fiction, it can manifest itself in a variety of ways: