; Figure 8You can learn to distinguish venomous snakes from nonvenomous species by their color and pattern. Consequently, how can you tell the difference between a poisonous and nonpoisonous snake? The Black Mamba: The Facts About One of the Most Venomous Snakes on Earth But underneath their scaly skin, they possess muscles, bones, lungs, intestines, a heart and a liver, just like other vertebrates. While non-venomous snakes have a rounded head, venomous snakes have a more triangular-shaped head.