The field of cryptozoology is one of the most interesting of paranormal phenomena. The existence of a cryptozoological monster does not in itself change life in the way ghosts or aliens would, but does suggest a mystery that pervades beyond our own current understanding of the world beyond us. But what exactly constitutes a cryptid as opposed to a normal undiscovered animal?
George M. Eberhart has defined a cryptid using ten points of identification mixed with six points of exclusion. Creatures that fit into the category of cryptozoological creatures must fit one (or all) of the criteria in order to be considered a true creature of the unknown, but none of the excluding principles.
First, we take phenomena such as big cats such as panthers and tigers. While these creatures themselves are not fantastic or undiscovered, their appearance in areas they would not ordinarily be found or able to survive suggests some force beyond the manmade. A lion appearing in Africa is not a cryptid, but appearing in a gas station in Oklahoma by unknown means would be.
Creatures that are far beyond the size they normally would be are considered cryptids such as rats or birds of unusual sizes. This classification comes about either with or without human interference assuming it is accidental (such as mutations due to radiation or toxins.)
Creatures that were once considered alive but are now generally considered extinct could be categorized as cryptids if they suddenly appeared. Dinosaurs, though once common in the world would be considered cryptids today as they are largely considered extinct. The mysteries of Nessie and Bigfoot have both been compared to extinct creatures that once inhabited the Earth. Point five is regarding creatures now dead surviving far beyond when they would have normally been considered extinct. A dinosaur discovered alongside human remains would be an example of this.
Myth carries with it tales of fantastic creatures such as the dragon. If one were to see a dragon or any other mythical creature it would largely be considered a cryptid. Similarly, creatures of modern folklore such as the Beast of Bray road, the Mothman, and the Chupacabra, while often related to other phenomena such as ghosts or extraterrestrials re generally thought themselves to be cryptids. As these creatures are often relegated to the realm of hoaxes or simply stories, any hoaxes arising (such as the wild Haggis or Jackolope) are also considered to be cryptids. Though they are manmade, they fit into the category of unknown or manmade wild creatures.
George Eberhart’s classification system is generally the most widely accepted system of categorizing cryptids and other unnatural creatures, but is certainly not the only one out there. If you wish to create your own classification system, try thinking about how your classifications deal with the outside phenomena such as ghosts and aliens. If a cryptid is discovered and confirmed, is it still a cryptid?
It should be noted that the giant Panda of southeast Asia was once considered a cryptozoological creature until its existence was confirmed last century. Perhaps more of these creatures will one day find themselves on the list.