This list will be describing some of the animals whose existence was once considered mythical; regular animals that had, at one point, been put into the same category as Bigfoot or a Yeti.
Kraken (Giant Squid)
It's likely that we've all heard of this one. The Kraken, described as a giant sea monster, is depicted as an aggressive creature able to sink ships and, according to the Cryptid Wiki page, is one of the largest cryptids in existence. It is a popular monster in stories and movies. It is likely, however, that this cryptid can be explained as being a Giant Squid, which is an elusive creature that hadn't been documented alive in video or photograph until the early 2000s. Until then, only carcasses that had washed up on shore and photos of the carcasses were available for study. The lack of documentation was a big part of why its existence was believed to be a myth for so long.
Canvey Island Monster
This is one of my personal favorites. The Canvey Island Monster is the name given to the carcass of an animal that washed on shore on Canvey Island. It was described as being 2.4 ft long, having gills, bulging eyes, and reddish brown skin. The carcass was cremated after zoologists deemed the creature not to be a threat to the public. A year later, in 1954, a carcass with a similar description to the last also washed up on shore. This one was studied further and was found to be much larger than the previous one and is now believed to have been the carcass of a monkfish.
The Devil Bird, AKA the Ulama, is a bird known to give off humanlike shrieks from within the jungle. The cries of the bird are believed to be a bad omen, often said to lead to death, according to Sri Lankan folklore. It wasn't until 2001 that findings showed the identity of this animal as being the Spot Bellied Eagle Owl, as it fits with many of the descriptions. However, there is still some debate over whether this is actually the identity of the animal.
While it seems weird to think about today, it's understandable that such a strange looking creature was, at one point, considered a hoax. The platypus was first encountered in 1798 by European explorers in Eastern Australia. The explorers sent back descriptions of the animal they encountered—a venomous, egg-laying mammal that appears to be a combination of a duck and a beaver. It definitely sounds like something someone had just made up. It wasn't until years after British scientists decided the animal was a hoax in 1799 that the existence of the platypus was actually proven.
The Okapi is described as a combination of several creatures—a donkey, zebra, and giraffe. This strange description led western science to believe the creature to be a myth, even though they had been presented with skins of the animal. It was described as the "African unicorn" due to its fantastical descriptions. It wasn't until the Okapi's live capture that its existence was recognized by science.
Knowing many of the animals that we know now were once considered cryptids and myths, it makes me wonder...what does this mean for many of today's popular cryptids? Will we find out that Bigfoot is nothing more than a forgotten species of ape? Or maybe the Loch Ness Monster is just an elusive fish? Or, who knows, maybe they can all be explained in one way or another; just a regular, non-supernatural creature, mistaken as myth.