As their name implies, diamondback water snakes, or Nerodia rhombifer rhombifer, spend most of their time in freshwater aquatic habitats, such as rivers, lakes and ponds. Diamondback water snakes are often mistaken for cottonmouth moccasins since both species live in freshwater environments. However, diamondback water snakes swim with their entire body underwater -- except their head -- while venomous snakes swim on the water's surface. As adults, diamondback water snakes may grow up to 4 to 5 feet in length, making them one of the largest water snakes in Texas. Frogs, fish and small mammals are the main items in the diamondback water snake's diet.
Western diamondback rattlesnakes, or Crotalus atrox, live in western and southern Texas' desert regions. These snakes may also live in grasslands and elevated regions of up to 7,000 feet. Although the diamonds on the snake's dorsal area are black, the base skin color of western diamondbacks is brown or gray. This snake species is also one of the longest venomous snakes in Texas, ranging from 6 to 7 feet in length. When hunting for prey, western diamondbacks often hide underneath brush or rocks and wait for their intended victims to pass by before they strike. Two male western diamondbacks will wrestle for the attention of a female snake.
Both diamondback water snakes and western diamondback rattlesnakes have black diamonds stretching down the length of their dorsal region. Diamondback water snakes are often mistaken for venomous moccasin snakes because they both have arrow-shaped heads. However, these snakes may be identified by the lack of pits, or grooves, between their eyelids. Western diamondback rattlesnakes are pit vipers, which mean their eyelids surround a pit on top of their head. Also, western diamondback rattlesnakes have rattles attached to the tip of their tails; diamondback water snakes do not have rattles.
Diamondback water snakes and western diamondback rattlesnakes have similar behavior traits. Both snakes are nocturnal, meaning they are most active at nighttime. When they feel threatened, these two snake species will shake their tails as a warning to humans before biting. The only difference is a rattling noise is heard when western diamondbacks shake their tail. As an extra measure of defense, diamondback water snakes will emit a musky odor to ward off potential predators.