south american rattlesnake viper (crotalus durissus) - cascavel

america animal biology brazil cascavel coldblooded crawl creature crotalus durissus dangerous deadly ectothermic fangs fauna latin lethal natural nature pit viper poison poisonous portrait predator rattle rattler rattlesnake reptile reptilia reptilian scales serpent snake snakes south american species tropical venom venomous viperidae wild wildlife zoology