Relationships can be complicated, especially in the wild. There are dozens of ways for creatures to couple up, whether they’re microscopic bacteria or massive jungle mammals. But as is true for human, there’s no one-size-fits-all in the animal kingdom—and no shortage of variety in reproductive and parental habits. 

In the act of furthering their species, male and female animals undertake distinct sex roles. The term doesn’t just refer to their part in copulating, but the specific tasks they fulfill in mating and parenting. A common theme in nature’s courtship world is one female choosing a mate from among competing male suitors, then raising her young, predominantly alone.

Male humpback whales, for example, compete for females and leave calf care to