The Biology Unit is dedicated to the international cooperative study of biological postage stamps and related material.
The journal Biophilately covers new zoological and botanical stamp issues worldwide.
These pages feature stamps of animals which once were or are still considered legendary, but which may
actually exist. Stamps of animals thought to be extinct but which have been found alive are also featured.
Other stamps depict supposedly extinct animals for which sightings comtinue to occur. All of these
animals are called "cryptids." Cryptozoology is the study of cryptids.