Hermaphrodite flatworms, a master-of-disguise octopus and a fish that 'walks' on dry land are among the unusual underwater critters examined.

A look at weird animals, from those that fend off predators by squirting blood from their eyes, to those which eat their partners after mating

Get ready to brush feathers with the freakiest denizens of the winged world as we look at the planet's wackiest and most fearsome fliers.

From sex-changing fish to rodents that mate themselves to death, a look at some of the odder ways animals pass on their genes.

Including bees that carry out a stealthy hive coup, giraffes making use of their dense skulls, and the jaws of the fearsome Tasmanian devil.

Animal parallels with our behaviour include faithful pigeon husbands, dolphin gangsters, and bees in trouble for getting drunk on the job.

Nat Geo WILD explores some of the world's most bizarre creatures ' from odd eaters to strange swarms ' to uncover nature's Freaky All-Stars. Meet the liger ' this offspring of a male lion and female tiger can be twice the size of its parents combined. And when it comes to amazing powers, the springtail has earned its bragging rights. The tiny bug can leap more than 6 inches in the air, the equivalent of a human jumping over a skyscraper!

Stunning mutations, shocking survivors and freakish feats, all caught on film. These stories are so bizarre that they seem impossible -- meet the weirdest oddities of the animal world. In California, one family's pet lizard gains local notoriety for having two heads. In Missouri, go scuba diving with a chimpanzee. Then, travel to Florida to meet an adorable kitten with five legs, and then meet a cockatoo that raises an important question -- is a bird still a bird if it has no feathers?

Witness freak encounters, unexpected assaults, and killer animal instincts -- these are the world's weirdest sneak attacks. In South Africa, a cyclist is suddenly slammed by an antelope traveling at 30 mph. In North Carolina, a 250-lb gator wanders into a highway ditch and the relocation efforts are disastrous. Other encounters include a 24-foot-long anaconda loose in a town and a man who discovers how agonizing it can be to have a fish burrow into your urethra.

Cameras roll as unsuspecting animals are caught behaving badly. From indiscriminate mating to animals on the loose, some creatures cannot be tamed. Meet a male deer who, driven by his raging hormones, desires a lot more from a girl who approaches to take a picture with him. When a black bear's cub gets stuck in a garage, the mother desperately tries to claw her way through the door. And go on a safari where a hippo smashes into a jeep and makes the family fear that it will attack again.

Freaky Eats whets viewers' appetites for some stomach-churning animal meals. From fecal foraging to postcoital snacks and strange local delicacies, see how animals -- and humans -- go to any lengths to get fed. Bird watchers at a lakeside park are shocked to see a pelican swallow a one-pound pigeon whole. And consuming raw toads could have deadly consequences, but that doesn't stop one courageous foodie from snacking on the exotic delicatessen.

In the battle for survival, brawn isn't always enough to keep you alive. Animals have learned to use their brains to solve the eternal problems of getting food, finding shelter and protecting family. From whales that create bubble walls to catch their fish, to dolphins that work with humans to catch their dinner, to prairie dogs that speak their own language. These brainiacs will have you cowering behind the sofa as they flaunt their intelligence and apply logic to fulfill instinctual needs

Billions of years of evolution and more than 1 million species of animal have created very weird world and some very bizarre body parts. From sex-crazed slugs to Kung Fu crustaceans, from blood-firing lizards to zombie snails, we journey from the ocean depths to deserts and tropical rainforests to reveal that for some creatures, the truth really is stranger than fiction. We showcase some of the strangest, most shocking animal appendages on the planet, and uncover their evolutionary advantages.

On the frozen wastes of Antarctica, a mother-to-be Adlie penguin sells her body for stones. In deepest, darkest Africa, chimpanzees trade meat for sex. In Canada, a post-hibernation gathering of garter snakes becomes a frenzied orgy. A redback spider eats her partner alive while they're still mating. Are these animals behaving badly? Or is the drive to reproduce so fundamental in the animal kingdom, that "anything goes"? Meet the world's weirdest friends with benefits.

If it creeps, crawls, buzzes or sheds its exoskeleton, there's a chance it could cure an illness that's stumping modern medicine. Parasitic worms, flesh-eating maggots, blood-sucking leeches, and skin-nibbling fish -- man runs from these creatures and often tries to eradicate them. But scientists and MDs are finding out just how much we need these creepy-crawlers to stay healthy. We explore the healing properties of the animals many think are disgusting, but sometimes turn out to be lifesavers.

Nat Geo WILD explores nature as it gets rolling drunk and spaces out, and delves into the importance, or lack thereof, of intoxication in the animal kingdom. Meet monkeys that binge drink and throw frat parties, elephants that go on drunken rampages through villages and lemurs that get high off millipedes. And when a jaguar's hunting skills may have been enhanced by chewing on psychedelics, scientists question whether or not there are evolutionary benefits to psychoactive compounds.

The early days for any species are precarious. Nat Geo WILD reveals the World's Weirdest methods employed by mothers and their offspring to sidestep and outwit their predators. Stealth, cunning, disguise, poison -- no trick is too low down or too dirty for parents who want to make sure their babies get a head start over their hungry foes. And marvel in the wealth of evolutionary adaptations that give these newborns a chance to flourish. It's life but not as you might know it.

Nat Geo WILD goes behind closed barn doors to reveal some of the most bizarre farms, farming methods and farmers on the planet. From the unusual to the downright dangerous, it's a rarely seen side of farming. Visit a farm in Utah that is home to spider goats, the world's first mammal/arachnid hybrids. In Thailand, one farmer is using elephants to produce coffee. And visit a leech farm in Wales where the bloodsucking creatures are used for medical science.

High in the frozen Japanese Alps, female snow monkeys engage in same-gender sex. Across the African savannah, "Lion Kings" enjoy intimate male friendships. A pretty seahorse is not just a dad, he's a pregnant dad. And a Mexican whiptail lizard is about to experience a virgin birth. In nature, gender is as flexible as life itself. Meet the World's Weirdest Swingers.

Mass animal deaths are occurring across the globe. Should we all be freaking out about the end of the world? Or are there logical explanations? World's Weirdest: Animal Apocalypse features the puzzling cases of animals behaving bizarrely: millions of mice overtaking farms and buildings, hundreds of whales beaching on a shore, thousands of blackbirds suddenly raining from the sky and frogs spontaneously exploding.

The Season 5 premiere examines animals that have adapted in order to survive. Included: the moray eel that has evolved a second set of teeth to help swallow; the Komodo dragon that kills using bacteria; and sand tiger sharks who eat their siblings in the womb.

A look at beavers building emergency bunkers and spiders preparing traps to catch their next meal.

Sharks are one of the oldest species on the planet, so they have had plenty of time to evolve and develop some of the weirdest and most diverse skills and survival tactics. Discover the odd behaviors of sharks of all sizes, from the vicious hunters to the scrappy bottom-feeders, as they have never been seen before.

Parenthood practiced by naked mole rats and egrets.