Cynocephaly

The characteristic of cynocephaly, /saɪnoʊˈsɛfəli/ having the head of a dog—or of a jackal—is a widely attested mythical phenomenon existing in many different forms and contexts.

The word cynocephaly is taken (through Latin) from the Greek word κῠνοκέφᾰλοι kynokephaloi, from kyno– (combining form of κύων kyōn) meaning "dog" and κεφαλή kephalē meaning "head".

The same "dog" root is found in the name Cynomorpha ("dog-shaped") for a sub-group of the family Cercopithecidae, which contains many species of macaques and baboons.

Cynocephaly was familiar to the Ancient Greeks from representations of the Egyptian gods, Duamutef (Son of Horus), Wepwawet (The opener of the ways), and Anubis (the Egyptian god of the dead). The Greek word (Greek: κῠνοκέφᾰλοι) "dog-head" also identified a sacred Egyptian baboon with the face of a dog.

Reports of dog-headed races can also be traced back to Greek antiquity. In the fifth century BC, the Greek physician Ctesias wrote a detailed report on the existence of cynocephali in India, known as Indica. Similarly, the Greek traveller Megasthenes claimed to know about dog-headed people in India who lived in the mountains, communicated through barking, wore the skins of wild animals and lived by hunting. Herodotus reports claims by ancient Libyans that such creatures inhabit the east of their lands, as well as headless men and various other anomalies.

...
Wikipedia