The species can be found in extreme southernPanama, the Pacific coast of Colombia and northwesternEcuador. The species was first collected in 1938 from Santa Cruz de Cana, a 16th centurygold mine on the eastern flank of the Serranía de Pirre mountains close to the Colombian border. A second specimen from adjacent Colombia was collected in 1919 but not correctly identified until 2003. The species is now known from numerous records in Ecuador and Colombia.
Biology
Atractus clarki is a small, nocturnal species that preys mainly on soil-dwelling invertebrates like earthworms. This snake is characterized by its brown dorsal pattern and lighter ventral side, with a bright red collar around its neck and head that they rely on as a defense tactic towards predators. Atractus clarki may represent a relatively ancestral form based on the shape of its reproductive organs. The specific physical appearance of Atractus clarki differs between male and female. Females are typically larger than males, with males having slightly different dorsal patterns. The species is found in warm, humid climates among soil and leaf litter. It is oviparous.