It was during this exploration of Cameroon’s rainforest that Sanderson first encountered a creature the locals called Olitiau. Described as a giant bat like creature with a wingspan between 10 to 12 feet in length, this monstrous avian is reportedly most active in the twilight hours. In 1932, while exploring a river system in the Assumbo Mountains, in one of Cameroon’s rainforests, Sanderson and his hunting partner Gerald Russell were reportedly attacked by an Olitiau as they were shooting smaller bats along a stream.

According to Sanderson the Olitiau’s lower jaw hung open displaying huge white teeth that were a good two inches in length, its body was of a coal black and did not appear to have any hair. When Sanderson reported this attack to his native guides they were reportedly so excited that they dropped everything and set out in search of the winged beast.

Some researchers have speculated that the Olitiau sighted by Sanderson was, and still is, a surviving species of Pterodactyl, a form of flying reptile thought to have died out some 65 million years ago along with the dinosaurs. Others believe that the creature may be a species of giant bat, more than doubling the size of the world’s largest known bat, the tropic flying fox which has a maximum wingspan of over 6 feet. The belief that the Olitiau may be a giant bat is shared by Sanderson who is quoted as calling this beast the “granddaddy of all bats.”