The top row displays the defining features of a rattlesnake. From left to right, a rattle on the tail, a triangular head, and hinged fangs.
One way to determine if a snake is venomous is to look at its underbelly. If there is a single row of scales leading to the anal plate, the snake is venomous.
Jacob L. Heller, MD, MHA, Emergency Medicine, Virginia Mason Medical Center, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.