Question

Spotted hyenas are an unusualspecies. They are extremely social and have very complex socialbehavior. The females are extremely aggressive and are dominant tothe far less aggressive males. Female genitalia is extremelymasculinized with no external vagina and a hypertrophied clitoristhat resembles a penis in size, shape, and the ability to becomeerect. They mate and give birth through this organ, which causes asmany as 18% to die during their first birthing and 60% of the survivors to lose theirfirstborn young.

This is a female.
Note the pseudo-penis.

This is a female.
Note the pseudo-penis.

Several hypotheses have been floated as to why such a thingwould evolve. For each of these hypotheses, lay out thefollowing:

• What sort of evolutionary process produced the masculinizedgenitalia?
• What evidence would you need to support/refute thathypothesis?

Hypotheses:

• Mimicry: Females are using these masculine genitalia to mimicthe submission rituals of the males.

• Anti-Infanticide: Females are aggressive as a countermeasure tomale infanticide (males killing infants). The aggressiveness iscaused by increased androgens (male sex hormones like testosterone)in the females, which in turn causes masculinized genitalia.

• Competition: Dominant females produce more cubs and her cubshave a strong advantage in access to meat. The aggressiveness iscaused by increased androgens (male sex hormones like testosterone)in the females, which in turn causes masculinized genitalia.