All Facts | Animals Do It Too

The Longest Relative Penis in Nature

Barnacles have penises up to 8 times their body length — the longest ratio of any animal on Earth.

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.

Till Death Do Us Part (Literally)

Male anglerfish permanently fuse to females, their bodies merging until the male is nothing but a pair of testes attached to the female's body.

Penis Fencing

Hermaphroditic flatworms fence with their two-headed penises — the loser gets pregnant and must bear the energy cost of producing eggs.

Traumatic Insemination

Male bed bugs bypass the female's reproductive tract entirely, stabbing through her abdomen to inject sperm directly into her body cavity.

The Ultimate Sacrifice

When a male honeybee mates with the queen, his genitals explode with an audible pop, killing him instantly.

Losing Your Head Over Love

Female praying mantises sometimes eat males during or after mating — but surprisingly, this only happens about 13-28% of the time in the wild.

Death-Defying Aerial Romance

Bald eagles court by locking talons mid-flight and cartwheeling toward the ground, only separating at the last moment before impact.

The Biggest of All

Blue whales have the largest penis of any animal — up to 10 feet long and weighing around 400 pounds.

Bird's Biggest Secret

The Argentine lake duck has the longest penis relative to body size of any bird — up to 17 inches, longer than the duck itself.

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.

Make Love, Not War

Bonobos use sex for conflict resolution, greeting, and social bonding — engaging in sexual activity regardless of gender, age, or reproductive state.

Masters of Pleasure

Dolphins have sex for fun, masturbate creatively, and have functional clitorises — making them one of the clearest examples of non-human sexual pleasure.

The Taste Test

Male giraffes headbutt females to make them urinate, then taste the urine to determine if she's fertile — a behavior called the Flehmen response.

Golden Showers of Love

Male porcupines woo females by standing on their hind legs and spraying them with urine from up to 6 feet away.

The Swimming Penis

Male argonaut octopuses have a detachable, sperm-filled arm that swims to the female on its own — scientists originally thought it was a parasitic worm.

The 30-Minute Mating

Boar ejaculation can last up to 30 minutes — one of the longest mating durations of any mammal.

Finding Nemo's Real Story

All clownfish are born male, and can permanently change to female — meaning in Finding Nemo, Marlin would have become Nemo's mom.

Chew It Off

When banana slugs get stuck during mating (their penises can be as long as their bodies), one partner may chew off the other's penis to separate.

Forked for Her Pleasure

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

Dad's Having the Baby

Male seahorses are the ones who get pregnant and give birth, carrying up to 2,000 babies in a specialized brood pouch.

The World's Largest Orgies

When red-sided garter snakes emerge from hibernation, up to 75,000 gather in writhing 'mating balls' — some of the largest mating aggregations on Earth.

Love Through Poop Spraying

Male hippos court females by spinning their tails like propellers while defecating, spraying feces in all directions to spread their scent.

Voluntary Cannibalism

Male redback spiders actively somersault into the female's fangs during mating — being eaten doubles their paternity success.

Ten Sex Chromosomes

While humans have 2 sex chromosomes (XX or XY), platypuses have 10 — the most complex sex determination system known in mammals.

Sex So Intense It's Fatal

Male antechinus mate so frantically for 2-3 weeks that they die from stress — their fur falls out, they become blind, and their immune system collapses.

The Most Stressful Handoff

Emperor penguin parents must transfer their egg from mom to dad in -40°C weather — if it touches the ice for too long, the embryo dies.

Eating Your Siblings in the Womb

In sand tiger sharks, embryos eat their siblings in the womb — only the two largest (one per uterus) survive to be born.

Males Not Required

Some whiptail lizard species are entirely female and reproduce through cloning — but they still perform mating rituals with each other.

The Sounds of Slow Love

Giant tortoises make loud groaning sounds during mating that can be heard from far away — and mating sessions can last several hours.

Death by Celibacy

Female ferrets can die if they go into heat and don't mate — prolonged estrogen exposure causes fatal bone marrow suppression.

Removing the Competition

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

Babies Burst from Mom's Back

Surinam toad eggs embed into the mother's back skin, where they develop for 3-4 months before fully-formed toadlets burst out of her back.

The Richest Milk on Earth

Harp seal milk is about 50% fat — the fattiest of any mammal — allowing pups to gain 5 pounds per day and be weaned in just 12 days.

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'.

The Ultimate Size Difference

Female blanket octopuses are 40,000 times heavier than males — the most extreme size difference of any non-microscopic animal.

Polyandrous Bird Moms

Female jacanas mate with multiple males, then leave each male to incubate and raise the chicks alone while she defends territory and finds more mates.

Marsupial Double Standard

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

Seven Seconds in Heaven

Chimpanzee copulation lasts an average of just 7 seconds — about as long as it takes to read this sentence.

Blink and You'll Miss It

Male mosquitofish can complete mating in under one second — among the fastest sex acts in the animal kingdom.

The Multi-Week Lockup

Some stick insects remain coupled during mating for up to 10 weeks — among the longest mating sessions of any animal.

Chewing Off Your Own Penis

Banana slugs sometimes chew off their partner's penis after mating — or their own if it gets stuck. The penis doesn't grow back.

50 Times a Day for Days

When a female lion is in heat, she may mate with the male up to 50 times per day for 4-5 days straight — totaling 200+ copulations.

Sex That Kills

Male antechinus mate so intensively — up to 14 hours at a time — that every single male dies within weeks of the mating season.

Sex as a Social Tool

Bonobos have sex multiple times per day in various combinations — male-female, female-female, even adult-juvenile — using it to resolve conflicts, reduce tension, and strengthen bonds.

The 24-Hour Window

Female giant pandas are only fertile for 24-48 hours per year, making them one of the hardest animals to breed in captivity.

Mating Once a Decade

Kakapos only breed every 2-4 years when rimu trees fruit heavily — and some individuals have gone over a decade between breeding attempts.

Snow Monkey Solo Sessions

Japanese macaques frequently masturbate — both males and females — and researchers have documented them using tools and creative techniques.

Evolutionary Self-Care

Male Cape ground squirrels frequently masturbate to ejaculation — scientists believe it's a strategy to keep sperm fresh for competition.

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.

Flipper Fun

Male walruses have been observed masturbating with their front flippers — aided by their enormous penis bone.

Rubbing One Out (On a Tree)

Male deer have been observed achieving erections and apparent ejaculation while rubbing their antlers on trees — behavior some researchers interpret as masturbation.

Climate Change Babies

Grizzly bears and polar bears are mating in the wild, producing fertile 'grolar bear' or 'pizzly bear' hybrids — a consequence of climate change pushing their ranges together.

All-Female Fish Army

Amazon mollies are an all-female species that 'steals' sperm from males of other species to trigger reproduction — but doesn't use any of the male's DNA.

When Dolphins Meet False Killer Whales

Wholphins — hybrids of bottlenose dolphins and false killer whales — have been born both in captivity and documented in the wild.

The Biggest Cat That Shouldn't Exist

Ligers — offspring of male lions and female tigers — can grow to over 900 pounds, making them the largest cats on Earth, bigger than either parent species.

10,000 Years of Sterile Offspring

Humans have been breeding mules (horse × donkey) for over 10,000 years, despite knowing that nearly all mules are sterile and can't reproduce.

Confused Waterfowl

Male ducks are notorious for attempting to mate with other species — researchers have documented them trying with over 40 different bird species and even other animals.

Nature's Interior Designers

Male bowerbirds build elaborate structures decorated with colorful objects to attract females — some even use forced perspective to create optical illusions.

Tiny Dancing Machine

Male peacock spiders perform elaborate dances while flashing brilliant colors — but if the female isn't impressed, she'll eat him.

The Red Balloon Display

Male frigatebirds inflate a massive red throat pouch to the size of a balloon, then sit for hours hoping females flying overhead will be impressed.

Inflatable Pink Nose

Male hooded seals inflate their nasal cavity into a pink balloon AND can blow a red membrane out of one nostril — both used to impress females.

The Exploding Chest Display

Male sage-grouse gather at traditional 'leks' before dawn, inflating yellow chest sacs and making bizarre popping sounds to compete for females.

Synchronized Light Shows

In some firefly species, thousands of males synchronize their flashes perfectly — creating waves of light that roll through the forest.

The Moonwalking Bird

Male red-capped manakins perform a rapid 'moonwalk' — sliding backwards along branches so fast it looks like they're gliding.

Romance Through Regurgitation

White-fronted parrots show affection by vomiting into each other's mouths — and the male vomits into the female's mouth before and during mating.

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 12-Foot Journey

Female elephants have the longest reproductive tracts of any land mammal — up to 12 feet from vulva to ovary.

The Twin Clitorises

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

Sealed Shut Until Mating Season

Mouse lemurs and dwarf lemurs develop a membrane that seals their vaginal opening completely closed outside of breeding season.

The Sealed-Off Females

Female European moles have 'ovotestes' that produce testosterone, and they have no external vagina except during breeding season.

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.