Crypto zoology is often disparaged as myth peddling rather than a science. It is often coupled with the paranormal, in all its various guises including those that are shorthand for hoaxes.
The word Crypto zoology comes from the Greek; crypto meaning hidden and zoology, the study of animals, therefore the combined meaning is the study of hidden animals. Animals within this area of study are called cryptids. They include the Loch Ness monster, big cats in countries where they are not native, Bigfoot, Yeti, Sasquash, the Loch Ness Monster and many other creatures. They are the creatures outside of conventional science, the ones that established science deems fictional. They may seem fantastic or quite commonplace but science dismisses them all.
It is easy to dismiss the sightings of cryptids as the result of too much cheese for supper, publicity seeking individuals, mistakes or hoaxes. Yet for years the authorities and scientific "experts" resolutely dismissed reports of big cats roaming the English countryside. Yet there is documentary evidence that large wild cats have been shot, captured and run over by vehicles. A Freedom of Information Act request resulted in two recorded sightings of big cats by credible witnesses. Gloucester police take sightings of big cats in the Forest of Dean seriously. Many people have come forward and admitted that they have released large cats into the wild, either as a result of The Dangerous Wild Animals Act 1976 or because another keeper of illegal wild animals in their area has been prosecuted. There is also some evidence that these animals are breeding in the wild successfully. The areas where big cats have been seen are the remote and sparsely populated. Although some sightings can be attributed to mistaken identity, or over-exuberance, there are still those that are credible sightings from creditable and knowledgeable witnesses.
Fishermen and sailors told stories of giant squid for centuries, Victorian scientists dismissed them as tall stories and that opinion prevailed amongst establishment scientists until giant squids were found. Now giant squids are part of the "official" zoology. The coelacanth, too, had been seen by mariners and it, too, was dismissed by scientists until one was found.
By rejecting, totally, the possibility of these creatures established science discourages those who would study the reports and gather the evidence to disprove or prove their existence, since to do so would be professional suicide.
Crypto zoology will be a recognized science when established science stops being so arrogant as to assume that humans know everything, there is to know, about their planet. There are huge and remote areas of the Earth that have never been properly studied. How on Earth can science say that all animals are known to science and that anything else is the figment of a fevered imagination?