Ever wonder what scientific category of animal Bigfoot or the Loch Ness Monster fit into? The answer: Cryptids.
Cryptids is the larger classification for animals unknown to science. Cryptozoology is the term for those who study -- or go in search of -- these creatures.
Take a look at (or perhaps imagine) some of the most famous cryptids.
Whether you call it Bigfoot, Sasquatch or Yeti, this ape-like cryptid has eluded science since -- well, since science began trying to confirm its existence.
As with most cryptids, the legend goes back centuries to native populations who told stories of large, ape-like creatures wandering the woods. For primatologists such as the very famous Dr. Jane Goodall, these accounts are proof enough.
But scientific belief in Bigfoot has suffered from notable hoaxes, from fake casts of giant feet to doctored videos. In 2008, the "body" of a supposed Sasquatch was found to be nothing more than faux fur and rubber feet.
If Bigfoot does exist, sightings suggest that the creature would weigh several hundred pounds and be between 6 feet and 10 feet tall.
And, regardless of whether or not this cryptid exists, there's no denying the loyal following, fan base and flat-out believers who have devoted their lives and research to Bigfoot.
Also known as N’Haatik, or the Demon of the Lake, the legend of Ogopogo first appeared in Native American folklore.
Ogopogo makes his (or her) home in Okanagan Lake in British Columbia, Canada. As with most cryptids, its home territory makes it extremely difficult to find. The lake itself is large and deep, nearly 84 miles long and 860 feet at its deepest point.
The Canada's British Columbia tourism website, whose motto just happens to be "Super, Natural" claims there are, on average, six Ogopogo sightings each year.
If you're one of the lucky few to glimpse the famous monster, it's said to resemble a cross between a giant snake with the head of a goat or horse. Or, if you're a dinosaur buff, some say Ogopogo resembles a plesiosaur.
Despite its "monstrous" reputation, Ogopogo has quite the following of beloved fans. The city of Kelowna has commemorated the creature in everything from art to parade floats.
Above, Ogopogo is pictured selling apples in an ad from the 1920s.
Is that a ripple in the water or the famous Nessie of Loch Ness, Scotland? It's a question cryptozoologists have been asking for decades since the first modern-day sighting of one of the best-known cryptids in the world.
You've heard it all before. Loch Ness in Scotland is extremely large -- 22 miles long and more than 700 feet deep. So tracking down physcial evidence has proved difficult, even with modern technology.
While it's said there are recorded sightings of Nessie as far back as the 6th century, it's generally accepted that the term "Loch Ness Monster" made its modern debut in 1933. Famous photos, such as "The Surgeon’s Photo" fueled the search -- and the hoaxes.
Despite numerous sonar and other attempts to prove the existence of Nessie, there has never been any conclusive scientific evidence found.
The only proven fact about the Loch Ness Monster is its ability to bring in tourist dollars. These days you can take a 3-D movie tour of the Loch or rent a boat to take out on your own adventure in search of Nessie.
Cadborosaurus willsi, or Caddy, is one of the famous North American sea serpents, named for Cadboro Bay in Canada. Sightings of a similarly described creature have been reported from Alaska to Southern California. Other names include Pal-Rai-Yuk, Klematosaurus, Sarah the Sea Hag, Saya-Ustih, Hiyitlik, Tzarta-saurus, Sisiutl, Penda, Amy, Kaegyhil-Depgu’esk and Say Noth-Kai.
The Cadborosaurus is often described as having a long snake-like body with flippers and a camel-like head. Several creatures matching this description have reportedly been caught over the years. Many "sea serpent" finds have turned out to actually be Giant Oarfish, the largest bony fish known to man. Some photos, such as the one pictured above from 1907, were never definitely identified as anything more than a "sea serpent."
One of the most famous accounts of "Caddy" is from 1937 when one was said to have been found in the stomach of a whale. Photos and flesh samples were taken of the "creature." Alas, the samples were lost to science and the photos have proven to be inconclusive -- with some scientists saying the specimen was actually a fetal baleen whale.
"Champ" the resident lake monster of Lake Champlain, N.Y., pictured above, bears a striking resemblence in history and a similarly devoted following with other North American sea/lake cryptids.
Legend has it that the first sightings date back to the Native American tribes that lived in the region. Sightings were abundant in the 19th century and continue to this day, according to the Lake Placid/Essex County Visitor’s Bureau, which encourages Champ sightings with its "Board of Champ Sightings" and even an annual "Champ Day" the first Saturday each August in Port Henry.
The mythical, or perhaps real, creature has generated enough adoration that between 1981 and 1983, Lake Champlain's bordering states of Vermont and New York enacted legal protections for Champ.
Is this Alaska's own version of the Loch Ness Monster?
This still image, taken from a 2009 video shot by an Alaskan fisherman, is one of the most recent grainy snapshots up for sea serpent debate.
The overall length and shape of the "animal" lends itself to classification as the cryptid "Cadborosaurus," according to Paul LeBlond, co-author of the book Cadborosaurus: Survivor from the Deep, whom Discovery News reporter Jennifer Viegas interviewed for this article.