Male and female hyenas have, in general, similar variations in personality types. However, "assertiveness" is one exception. Why?
a. Males have to compete for access to females, so natural selection has favored the evolution of assertiveness in males, but not females
b. Males have very brutal mechanisms to establish hierarchical ranks; there is thus a strong selective pressure favoring assertiveness in males
c. Hyenas have matriarchal societies and females in this species have been favored by natural selection to have personality traits related to assertiveness
d. Assertiveness is mostly associated with female hyenas because males often attempt infanticide of other males' offspring, and females are the ones that prevent this