Cryptozoology is the study of rumored or mythological animals that are presumed (at least by the researcher) to exist, but for which conclusive proof does not yet exist; or are generally considered extinct, but occasionally reported. Those who study or search for such animals are called cryptozoologists, while the hypothetical creatures involved are referred to by some as "cryptids".
Invention of the term is usually attributed to zoologist Bernard Heuvelmans, who coined the word to mean "the study of hidden animals". Huevelmans' monumental 1955 book, On The Track of Unknown Animals is often seen as the disipline's genesis, but Huevelmans himself traced the scholarly origins of the discipline to Anthonid Cornelis Oudemans and his 1892 study, The Great Sea Serpent.
Huevelmans argued that cryptozoology should be undertaken with scientific rigor, but also with an open-minded , interdisciplinary approach. Furthermore, according to Heuvelmans, special attention should also be given to folklore regarding creatures. While often layered in unlikely, fantasic elements, folktales may contain grains of truth that could help guide those researching reports of unusual animals.
Some cryptozoologists align themselves with a more scientifically rigorous field like zoology, while others tend toward an anthropological slant or even a fortean perspective. The fringes of cryptozoology are often considered pseudoscience by mainstream biologists.
2.1 Primates and man-apes
While many cryptozoologists strive for legitimacy and many are respected scientists in other fields, and though discoveries of previously unknown animals are often subject to great attention, cryptozoology per se has never been fully embraced by the scientific community, and one cannot obtain a cryptozoological degree from any college or university.
Recently, however, Henry Gee , editor of the prestigious journal Nature, writes that cryptozoology "can come in from the cold"  due to the unexpected and startling discovery of Homo floresiensis (further details below).
A cryptozoologist may propose that an interest in such a phenomenon does not entail belief, but a detractor will reply that accepting unsubstantiated sightings is itself a belief. Cryptozoologists tend to be responsible for disproving their own objects of study. For example, some cryptozoologists have collected statistical data and studied witness accounts that challenge the validity of many Bigfoot sightings.
Scientists have demonstrated that some creatures of mythology, legend or local folklore were rooted in real animals or phenomena. Thus, cryptozoologists hold that people should be open to the possibility that many more such animals exist. In the early days of western exploration of the world, many native tales of unknown animals were initially dismissed as mythology or superstition by western scientists, but consequently proven to have a real basis in biological fact. Cryptozoologists often point out that natives often know a great deal more about their immediate environment (and the animals that inhabit it) than western investigators, and therefore suggest that, even today, thus far unproven tales and traditions regarding unknown undescribed animals in native folklore should not be summarily dismissed in the same way.
There are several animals cited as examples for continuing cryptozoological efforts:
Georges Cuvier's so-called "Rash Dictum " is sometimes cited as a reason that researchers should avoid "rash" conclusions: In 1821, Cuvier remarked that it was unlikely for any large, unknown animal to be discovered, not because they aren't conspicious, but because there aren't that many. Many such discoveries have been made since Cuvier's statement (though less than 50 in number). It's been argued that the chances of uncovering large, previously unknown vertebrates are very slender when compared to uncovering unknown invertebrates. It is the commitment to spectacular animals (mostly vertebrates) that makes cryptozoology's critics suspicious of sensationalism.