The Peryton is a mythological hybrid animal, combining the physical features of a stag and a bird. The Peryton was created and described by Jorge Luis Borges in his Book of Imaginary Beings, using a supposedly long-lost medieval manuscript as a source.
The Peryton is said to have the head, neck, forelegs, and antlers of a stag, combined with the plumage, wings, and hindquarters of a large bird, although some interpretations portray the Peryton as a deer in all but coloration and bird's wings. Some legends claim that the Peryton are the ghosts of sailors that have died far from home, and cast humanoid shadows. Another description of the Peryton describes it's shadow as that of a man until it kills one during its lifetime, at which time it starts to cast its own shadow.
In Borges' original Spanish edition of Book of Imaginary Beings, Peryton is written as peritio. The presumptive Latin origin of peritio would be peritius, which is also the Latin name of the fourth month on the ancient Macedonian calendar (Peritios, the moon of January). The connection of this, if any, to the peryton is unclear.
According to Borges, Perytons lived in Atlantis until an earthquake destroyed the civilization and the creatures escaped by flight. A Sibyl once prophesied that the Perytons would lead to the downfall of Rome.
Jorge Luis Borges' Book of Imaginary Beings original Spanish copy, Manual de zoología fantástica, was printed in 1957 and was co-written by Margarita Guerrero. Book of Imaginary Beings is generally accepted to be a fantasy book, and in it is predominantly contained creatures of imagination and mythology, such as Cerberus, the Chimera, and Centaurs. Jorge Luis Borges was also infamous for obscuring fact and fiction in his works. Objectively, Book of Imaginary Beings is not a reliable source, and the Peryton is, most likely, a hoax.