ward off potential predators of its own, the Horned Viper
rubs the scales of its back against one another, producing
a frightening, "rattling" sound.
There is an uncanny convergence in appearance and behavior
between the Horned Viper of the Sahara and the sidewinder
(a pit viper) of North America. Both move in a sidewinding
manner and both have "horns," perhaps to shade
their eyes. The sidewinder, however, like other rattlesnakes,
has a rattle on its tail. The horned viper
compensates by rattling its scale as a warning.