In many works cryptozoology is listed as a pseudo-science and one has to ask if this is fair. Science originally meant knowledge of any kind - it comes from the Latin scientia, which means just that. However, cryptozoology doesn't just search for unknown animals, it searches for legendary animals to see if any fact lies behind them. Now, one of the criteria for something being a science these days is that any proposition put forward must be falsifiable. If Bigfoot is a creature of legend, a scientist cannot falsify the proposition that it might be out there. Hence, many say cryptozoology is a pseudo-science.
One cannot really maintain such a standpoint, however: cryptozoology is the search to see if something is falsifiable or not. Scientists will have to expand their definitions of what science actually is, or else we'll never end up looking for the undiscovered, as I am sure there is much to discover about the cosmos which is at present not falsifiable - but that doesn't mean it isn't out there or that it is pseudo-scientific to suggest that it might be.