Evidence That Mythical Creatures Exist
Unicorns

Image Source / Good HousekeepingYou'd think that learning unicorns actually existed would be a dream come true (literally), but you might be a little disappointed when you find out what they actually looked like. Researchers have found, based on a skull fossil discovered in Kazakhstan, that a 'unicorn' existed around 29,000 years ago. But instead of a white horse with a rainbow horn, it looked more like a rhino.
Loch Ness Monster

Image Source / www.history.comTo confirm that the mythical creature said to roam Loch Ness in Scotland actually exists means to consider that it might just be a giant eel rather than the hoax depictions we've been led to believe. A scientific study in 2019, which took a DNA survey for organisms living in the loch, determined that the water contained a lot of eels. So if Nessie does exist, she's likely an eel!
Fairies

Image Source / Live ScienceFairies are mythical winged creatures that appear in folklore around the world. One of the most famous encounters with fairies was when Frances Griffith and her cousin took this photograph of dancing fairies which, at the time, was believed to be genuine, with many people believing the fairies were real. It later turned out that Frances had cut out the fairies from a book. But that doesn't stop modern day people still believing.
Mermaids

Image Source / National GeographicMermaids - half human and half fish - are part of sailing legend (or Disney legend if you're a fan of Ariel) but do mermaids exist? Yes. Well, kind of. The legend of the mermaid does come from a real-life creature, which is the less glamorous manatee! Manatees have been mistaken for mermaids by sailors in the past because of their human-like size, human-like fingers on their flippers and the fact that can even stand up in shallow water.
The Kraken

Image Source / NPR
Any Davy Jones fan will have wished this creature was real - or maybe not if you don't want your ship dragged down to the depths. Because, you know... we all have ships at our disposal. But anyway, the legend of the kraken actually came from a creature which very much exists - and although it doesn't have a pastime of sinking ships, it does dwell in the ocean - as the giant squid!
Dragons

Image Source / Mark Witton's Blog It's very unlikely there's a single person out there who hasn't dreamed about riding their own dragon and living their best Targaryen life. But the dragon has always been a very unreal, very legendary mythical creature. Or has it? The fact is, the legend of the dragon came from the very real existence of dinosaurs. But aside from that, we all know that dragons like the Komodo dragon or the Bearded dragon exist - they just can't fly or breath fire (that we know of!).
Pouakai

Image Source / The New York Times
This one comes from Maori legend, where the pouakai is a giant flying bird. It's said that it would swoop down and carry humans away to eat. So you might be rather disturbed to learn it actually existed... The pouakai was found to actually be the haast eagle, which is the largest to ever have existed. Its size, wingspan and weight meant it could easily pick up a human to carry off - which means there's every possibility it did!
Roc

Image Source / Scientific American BlogsIn mythology, the roc gives the pouakai a run for its money. This bird of prey was said to be so big it could lift an elephant off the ground. It was believed that the roc lived off the coast of Africa. In reality, the roc is believed to have been the aptly named 'elephant bird', which weighed half a ton, but couldn't actually fly!
Griffins

Image Source / Wikimedia CommonsThis mythological creature with the face, wings and front of an eagle and the tail end of a lion, unlike the real roc, could actually fly. It may be hard to believe this creature existed, but it's believed to have actually been a dinosaur (sort of) called the protoceratops, which walked on four legs and had a beak.
The Sea Serpent

Image Source / All That's InterestingAs if the Kraken or Loch Ness Monster weren't scary enough where water is concerned, we now learn the sea serpent existed. The folklore of the sea serpent tells of a fish-snake monster roaming the seas. The sea serpent is actually supposed to be an oarfish - which does look like a fish-snake. It's around 30 feet in length, but rather than cause chaos in the ocean, it likes to stay deep underwater.
The Yeti

Image Source / Dark Worlds QuarterlyWe all know of the huge, hairy monster spoken about by the people of Nepal and China. In 1921, British explorers believed they'd found the creature's massive footprints while they were climbing Everest. It's more likely that the 'yeti' is actually a type of human-sized bear which lives in this region, called “metoh-kangmi” by local guides, which translates to "man-bear snow-man".
Gorillai

Image Source / Warehouse 13 Artifact Database Wiki - Fandom
No, this isn't just gorilla spelt wrong! The gorillai, according to folklore, was the name given to a tribe of 'hairy and rude' people that an explorer came across during the 5th/6th centuries. The creatures weren't found again until 1847. And then they were discovered to be, you guessed it... apes. And what we know today as gorillas!
Moby Dick

Image Source / Smithsonian Magazine Moby Dick isn't so much a myth as a fictional whale, but he's built a sort of legend in his own right as the White Whale. In real life, a ship's captain in 1820 had his ship sunk by a whale - an 85-foot white sperm whale, to be exact, that gave way to the Moby Dick legend.
Direwolves

Image Source / Game of Thrones Wiki - Fandom These legendary creatures, most notably from Game of Thrones fame, are said to be gigantic wolves with a vicious nature, capable of easily taking down any enemy. In reality, dire wolves were, in fact, real animals, but they went extinct when the last Ice Age ended. The dire wolves weren't huge, but instead a similar size to normal grey wolves.
Imoogi Dragons

Image Source / WIRED This mythical dragon comes from Korean folklore, depicted as snake-like with four legs. They don't have wings, though, like common mythological dragons, and are often related to water. While they don't exist, in reality there is a similar creature called the titanoboa, which was the largest snake ever found. They died around 58 million years ago, though!
Blemmyae

Image Source / WikipediaThe legend of the 'Blemmyae' came from sailors speaking of 'wild men' in Asia and Africa. They were described as being headless and covered in hair, as well as having their faces on their chests. In reality, it's highly possible these were highly mistaken descriptions of gorillas. Another possibility is normal tribesmen were viewed from a distance with their heads lowered, making it look like their faces were at chest level.
Platypus

Image Source / National Geographic KidsOkay, so this one might be surprising, seeing as we already know the platypus exists. But there is actually a legend about the platypus that is very different to what we know one as today. When the platypus was first described and sketched, naturalists didn't actually believe such a thing could exist, so it turned into a mythological beast whilst being very much real!
The Bunyip

Image Source / WikipediaThe bunyip is a legendary creature of Australia said to lurk in swamps and creeks, and it's said to look like something between an emu and a crocodile. It's highly believed this creature actually exists, and The Murray River in particular is said to be a hotspot for sightings of whatever this creature is!
The Chupacabra

Image Source / BritannicaOf Puerto Rican folklore, this creature is said to be the size of a small bear and has spine along its back from neck to tail. It's also said to enjoy the blood of livestock. It's believed by the people of Puerto Rico to definitely exist, as one eyewitness claimed she'd seen the thing kill 150 goats!
The Dobhar-chú

Image Source / Coffee and CreaturesHailing from Irish folklore, this creature is said to be half otter and half dog. It's said to lurk along the coast. The creature was allegedly first encountered in the 17th Century when a woman was apparently killed by it, and many believe it's real, with the woman's headstone even including a depiction of the creature!
The Mokèlé-mbèmbé

Image Source / information.tv5monde.comThis is Africa's version of Scotland's Loch Ness monster. It's said to be a giant creature with a long neck that dwells in deep water. It's believed to exist, despite a few previous expeditions failing to find it, but people go looking for it in Lake Tele in the Congo River basin.
The Kappa

Image Source / The Storied ImaginariumIn Japanese legend, this child of the water is said to be a humanoid creature with the skin of a reptile, which lurks in ponds or rivers. Parents would tell tales of the kappa to warn children not to go near the water for too long. Kappa have been reported all over Japan, and while there's no proof the Kappa exists, it's said that it could be the hanzaki, which is a large salamander found in Kyushu.
The Thunderbird

Image Source / BirdNoteThis legendary bird comes from Native America, a bird so large its said to be able to carry a whale. Aptly named, it's also said it can cause thunder and lightning. Modern people have actually reported witnessing a bird in Alaska with a 20-feet wingspan. Scientists have been quick to say this is most probably a Steller's sea eagle, which could have started the thunderbird legends.
Hobbits

Image Source / The MirrorYou may have thought that the hobbits were a race of people entirely made up by J.R.R. Tolkien, but actually a race of people small in stature like hobbits appeared on the earth alongside regular-sized humans from 50,000 to 190,000 years ago. The remains of a 3-foot-tall adult woman were found in a cave in Indonesia, and through tests it was determined that there wasn't any other medical condition to cause short stature, as the skull was normal sized.
The Basilisk

Image Source / Snake Facts - Weebly
The basilisk is weirdly terrifying, because it's a massive snake but then it's crossed with a chicken. The myth goes that a basilisk is born when a rooster nests on snake eggs, resulting in a creature with a rooster's head, snake body, legs of a chicken and wings. Or, in the Harry Potter world, it's just a large snake. In reality, the basilisk could very much be the Egyptian cobra, which stares into its victim's eyes, holds the front part of its body upright and spits venom.
Werewolves

Image Source / Top Dog TipsWerewolves have been part of legend for a long time and have long since made their way into modern media. Behind the legend is actually fact, which saw wild animals and even household dogs being infected by rabies. If a person was bitten by a rabid animal, their correct posture could turn into one bent, crawling on the floor and see them foaming at the mouth. And if that person also had a lot of hair... there you go.
Aliens

Image Source / New ScientistNot so much a mythical creature, but definitely an area of 'do these things actually exist' controversy. The reports of alien visitations can be explained away by things like weather balloons or military crafts, but the fact is, life does exist on other planets, it just might not be thin green men landing on our planet.
Giants

Image Source / Strange RemainsSome legends of giants include the Irish giant Fionn mac Cumhaill said to have created (and destroyed) the Giant's Causeway. But of course, giants - or humans with a condition called gigantism - do exist in real life. In the Hunterian Museum, there are the bones of an 18th-century circus performer who had gigantism.
The Jackalope

Image Source / Zoo AtlantaThe mythological 'jackalope' is said to be a rabbit that has antlers, and sometimes you can find heads created by taxidermists on the walls of places in the Midwest. But a lot of locals stand by the fact the jackalope really exists, and have taken pictures of it. And then it turns out that within the mammal collection at the Smithsonian Museum was found a jackalope - a rabbit which had grown hornlike tumors from its head.
The Vampire Deer

Image Source / WCS Newsroom - Wildlife Conservation SocietyThe 'vampire deer' actually exists, but it's not a blood sucker at all. The name comes from the musk deer's protruding teeth which look like - you guessed it - fangs. These saber teeth are what the male deer use to fight. The creature is also sadly hunted for its scent glands, and may become extinct.