What exactly is cryptozoology? To get a hint, we take appart the word. "Crypto" meaning "hidden" and "zoology" meaning the study of animals. Therefore, cryptozoology is the study of hidden or unknown animals. It includes animals not yet proven to exist; animals of myth, legend, lore and fables; animals out of place, and animals thought to be extinct. Some examples of the animals not yet proven to exist would be Bigfoot, Chupacabra, or the Aswang. Animals of myth, legend, lore and fables would be the unicorn, dragons, or the cyclops. For animals out of place there may be a penguin in the Arizona dersert, the jaguar in North America, or allegators in Arizona rivers. The animals thought to be extinct would be the dinosaurs, sabertooth tigers, and Gigantopithecus (giant preshistoric gorilla species).
Cryptozoology is not considered to be a scientific field of study. In fact, it is considered a pseudo-science. In other words, there is no academic requirement to be a Cryptozoologist. This is not like the other fields of study such as zoology, anthropology, biology, botany, etc. You can not get a degree in cryptozoology. However, the study of cryptids relies upon the all the sciences name above and more.
In most cases the cryptid does not cooperate in any studies. Consequently, it is necessary to gather data and form theories from what is known through the other sciences. Unfortunatley, we have to operate that way until a sample of the species is available for study. Note that I said a sample. It is not necessary to have a body or carcass. We need not kill an already extremely rare creature even though it will not be considered an endangered species untill the existence is proven.
Cryptozoology uses the other sciences to better understand our cryptids. Biology is the natural science which studies life and living organizms. How they are built, their function, including growth, evolution, and distribution. The study of Zoology is the study of animals both living and extinct and inculdes classification, habits, distribution, and classification. This is very important to know to relate the cryptid to the proper branch of the animal kindom. If the cryptid is thought to be man-like then Anthropology is a great field of study which studies human kind, past and present. It looks at social structures, habits, and behavior. Botany is very important when working with cryptids. It is the study of plants, and gives us an idea where to maybe look for the cryptid if they have any food preferences. This may be determined by the study of scat (poo).
Since Cryptozoology depends on the other sciences so much the luxury of one fiield of science is not for the practicing Cryptozoologist. The better understanding of all the sciences greatly enhances the likelyhood, the cryptid will be identified and proven to exist.