Anatomy | Animals Do It Too

The Corkscrew Arms Race

Male ducks have corkscrew-shaped penises that spiral counter-clockwise, while females have vaginas that spiral clockwise — an evolutionary arms race.

The Four-Headed Wonder

Male echidnas have a four-headed penis, but only use two heads at a time, alternating sides with each mating.

The Trunk Down There

Elephant penises are prehensile — they can move independently, swat flies, and even scratch the elephant's belly.

Females With Fake Penises

Female spotted hyenas have a pseudo-penis — an enlarged clitoris so similar to a male's penis that even biologists struggle to tell them apart.

Triple Reproductive Tract

Female kangaroos have three vaginas — two for sperm and one for giving birth — allowing them to be perpetually pregnant.

Double Equipment

Male snakes and lizards have two penises (hemipenes) but only use one at a time — and they often alternate sides between matings.

Forked for Her Pleasure

Male opossums have a bifurcated (forked) penis to match the female's two-branched reproductive tract.

Removing the Competition

Male dragonflies have specialized penises that scoop out sperm from previous males before depositing their own.

Speed Dating with Explosions

A drone honeybee's entire mating apparatus everts and detaches in 0.3 seconds, with the force of ejaculation creating an audible 'pop'.

Marsupial Double Standard

Like other marsupials, male koalas have a bifurcated (forked) penis, while females have two lateral vaginas and two uteruses.

The 22-Inch Penis Bone

Walruses have one of the largest penis bones (baculums) of any mammal — up to 22 inches long — and they've been carved into art for centuries.

The Triple Vagina System

Female kangaroos have three vaginas — two for receiving sperm connected to two uteruses, and a central birth canal that opens when pregnant.

The 13-Fold Labyrinth

Harbor porpoises have up to 13 vaginal folds that may allow females to control which male's sperm reaches her eggs.

The Twin Clitorises

Female snakes have paired clitorises called hemiclitores — scientists had confused them with scent glands for years.

The Pendulous Pseudo-Penis

Female spider monkeys have such large, pendulous clitorises that early researchers thought all spider monkeys were male.

Vaginal Lock and Key

Snake vaginas co-evolve with male hemipenes — species with branched hemipenes have females with branched cloacas to match.

The Labyrinth Within

Dolphin vaginas contain complex spiraling folds that act as physical barriers — giving females hidden control over which matings succeed.

17 Facts