The natural world is full of examples that challenge our ideas about gender and sexuality. Our free-loving, bisexual cousins the bonobos live a lifestyle that runs in contradiction to everything we view as “traditional” human relationships, while seahorses famously switch sides, allowing males to give birth to their young. These well-known examples aren’t the only ones, though. Many species have anatomy and behavior that would make us second-guess our assumptions about gender, and especially about girls and women. Here are nature’s most empowered females from the animal kingdom:
1. Hyenas: Nature’s Butchest Females
When Western scientists first started observing hyenas, they believed that all hyenas were hermaphrodites. It was an easy enough mistake to make: female hyenas are pumped full of testosterone, making them bigger, stronger, and more aggressive than males. Even more surprisingly, females are born with large “pseudopenises”– enlarged clitorises that look and function almost exactly like male genitals. Females even give birth through these exterior genitals, and use them to mount both males and females in competitions for social dominance. Among hyenas, females are truly the ones who wear the pants.
2. Amazon Mollies: Nothing But Girls
Appropriately named after the mythical all-female tribe, Amazon mollies are one of just a tiny handful of species known to be only one sex. These live-bearing fish, which are native to Northern Mexico and close relatives of the guppy, thrive as a species despite the fact that they have no males to mate with. Amazon mollies instead reproduce by occasionally finding males of other species and then engaging in “false” mating with them. This imitated mating triggers the female to produce a brood of clones of herself, which she gives birth to after about a month. The fry, or baby fish, share absolutely no DNA with their “fathers” but are instead identical to their moms.
3. Whiptail: All-Lesbian Lizards
Like Amazon mollies, certain species of whiptail lizards are all female, but unlike Amazon mollies, they mate with each other. During mating season, these lesbian lizards seek out same-sex mates and then proceed to engage in “pseudocopulation,” in which one female lies on top of the other in an imitation of male-female mating. Shortly afterward, both females lay a clutch of eggs, with the female who was on top laying larger eggs than the female who was on the bottom. When the eggs hatch, the baby lizards are exact genetic replicas of their mothers. No one knows how it’s possible that whiptail lizards are able to evolve over time without males, since this self-cloning limits the species’ genetic diversity.
4. Marmosets: Daddy Does the Work
Most of the time, simply because of the biology of pregnancy and lactation, female mammals put most, if not all, of the work into rearing young. Marmosets, which are tiny monkeys who give birth to large twins, turn typical mammal gender roles upside-down, leaving Daddy to do almost all the work of childcare. Marmoset babies are so large compared to their mothers that she is left completely drained and weak after giving birth, but she gets a chance to recuperate: while she recovers, the twins’ father carries them around, nurtures them, and teaches them, and eventually feeds them solid food, only returning them to their mother occasionally to nurse. It’s a lot of work for a new dad, but goes to show that hard-working moms and absent dads, seen in many mammals, are by no means universal.