} It causes rapid paralysis and respiratory failure in its prey. Mexican Black Snakes are typically found in Northwestern Sinaloa and western Sonora. Add an Observation. } Relatively shy, you probably wont hear these snakes rattling away. As timely treatment saves lives, it is necessary to include and offer treatment in all emergency units of the country. The Mexican Horned Pit Viper (Ophryacus undulatus) is a rare and poisonous snake of the pit viper variety. Even if you dont think the snake that bit you was venomous, the best thing you can do is snap a picture of the snake and head to the hospital. Of all the snakes found across Mexico, surely one of the most deadly dangerous animals is the Fer-de-Lance. return "number" != typeof r ? Even if you dont feel any immediate symptoms, its best to go to the doctor anyway.