Gallifreyans

Gallifreyans are a fictional alien race featured in the British science fiction television series Doctor Who. They first appeared in the pilot episode of the programme, "An Unearthly Child" and was first represented in the form of actor William Hartnell as the First Doctor.

The Gallifreyans are an ancient humanoid race who hail from the planet Gallifrey. Physically, they look no different than an average Earth human, but biologically, they are quite different. One of the more notable distinctions between a Gallifreyan and an Earthling is the fact that Gallifreyans have two hearts. Many Gallifreyans are chrononauts, or, explorers of time, and have taken on the rank and function of a Time Lord.