On the Pacific versant, they occur in isolated populations in east-central and southern Mexico, Guatemala, El Salvador, Costa Rica and Panama.

[3] The common name alludes to the supposed ability these snakes have to launch themselves at an attacker during a strike, thereby bridging a distance that is equal to or greater than the length of the body.

[2] Campbell and Lamar (2004), on the other hand, describe this as greatly exaggerated, saying that actually these snakes are only able to strike about half of their own body length.

March (1929) wrote that M. mexicanus (M. nummifer) will hang on and make half a dozen punctures unless quickly and forcibly removed.

Laboratory studies suggest that Metlapilcoatlus venoms are unlikely to lead to consumption coagulopathy and incoagulable blood in humans.