Western pygmy rattlesnakes are often a pale gray with less spots than the dusky or Carolina Pygmies. Their dorsal stripe is also a bronze or dull orange color compared to the red of their sister subspecies. Any other rattlesnake species that occurs in the same area will have a significantly larger rattle, lack an orange stripe, and have more pattern than this species.

They prefer a variety of habitats across their range, in Arkansas they are associated with cedar thickets, in Louisiana and east Texas they are found in dry pine uplands, and in Tennessee they are found around the edges of lakes and swamps.

This subspecies has faced severe range declines in East Texas, Missouri and Louisiana due to habitat loss and possible human persecution. Diseases such as the fungus Ophidiomyces ophiodiicola , a.k.a. Snake Fungal Disease (SFD) may also play in role in the decline in populations with shorter warm seasons and ability to thermoregulate over-winter.

Like all pygmy rattlesnake subspecies, they target a variety of prey including amphibians, lizards and rodents. Young are born with yellow-tipped tails to assisting in luring prey.

This rattlesnake will give birth to 3-7 young per litter, and the young can be as small as 4 inches long! The rattle of a pygmy rattlesnake is used more like a luring device than a warning system. When rattling, a pygmy rattlesnake can only be heard up to a few feet away, and it sounds more like an insect than a rattlesnake.