The Martian Erloors are humanoid bat-like creatures with membranous wings and glowing eyes. Despite being almost the size of a man, and having wings that have somewhat degenerated to allow the development of hands at the tip, the creatures are still capable of flight owning to the weaker gravitational attraction of Mars. In addition to their hands, their feet are also prehensile, allowing them to hang on tree branches with relative ease. They appear to be strictly nocturnal.
The Erloors are worshiped by the humans of Mars - a race of short, overweight people who practice agriculture and domesticate animals, but have no knowledge of fire. The human Martians periodically offer their best animals to be sacrificed as food for the Erloors. If they fail to do so properly, the humans themselves may become victims of their parasitic gods.
- Le Prisonnier de la planète Mars, by Gustave le Rouge (1908)
- This species is curiously reminiscent of other Mars inhabitants from throughout science fiction. The Martian Invaders from H. G. Wells' The War of the Worlds bear no physical resemblance to them, but are also bloodsuckers. More to the point, the Martians from Wells' The Crystal Egg resemble the War of the Worlds kind but are also winged and capable of flight. In Arnould Galopin's Doctor Omega, the Martian Gliders resemble humanoid bats, only their wings are artificial and they don't appear to be vampiric. The Martian Dwarves from the same book, however, do use their tentacular fingers to suck blood. Furthermore, the Martian from It! The Terror from Beyond Space is also a vampire and has features somewhat reminiscent of a humanoid bat, although it doesn't have wings.