Rattlesnake Facts

Scientific Name: Crotalus or Sistrurus

Rattlesnake
Western Diamondback Rattlesnake.

Martin Harvey/DigitalVision/Getty Images 

Rattlesnakes (Crotalus or Sistrurus) are named for the rattle at the end of their tail, which makes a rattling sound as a warning to other animals. There are over thirty species of rattlesnakes that are indigenous to the Americas. While most of those species have healthy populations, some rattlesnakes are considered threatened or endangered due to factors like poaching and the destruction of their native habitats.

Fast Facts: Rattlesnake

  • Scientific Name: Crotalus or Sistrurus
  • Common Name: Rattlesnake
  • Basic Animal Group: Reptile
  • Size: 1.5–8.5 feet
  • Weight: 2–15 pounds
  • Lifespan: 10–25 years
  • Diet: Carnivore
  • Habitat: Diverse habitats; most commonly open, rocky areas, but also native to deserts, prairies, and forests
  • Conservation Status: Most species are Least Concern, but a few species are Endangered

Description

Rattlesnakes get their name from the distinctive rattle at the tip of their tail. When it vibrates, it produces a buzzing or rattling sound. Most rattlesnakes are light brown or gray, but there are some species that can be bright colors like pink or red. Adults are usually 1.5 to 8.5 feet, with most being measuring under 7 feet. They can weigh from 2 to 15 pounds.

Rattlesnake Tail
Close-up of a rattlesnake tail.  Robert Young/EyeEm/Getty Images

Rattlesnake fangs are connected to their venom ducts and are curved in shape. Their fangs are continuously produced, which means there are always new fangs growing in behind their existing fangs so that they can be used as soon as the old fangs are shed.

Rattlesnakes have a heat sensing pit between each eye and nostril. This pit helps them to hunt their prey. They have a form of 'heat vision' that helps them to locate their prey in dark conditions. Since rattlesnake have a heat-sensitive pit organ, they are pit vipers.

Habitat and Distribution

Rattlesnakes are found throughout the Americas from Canada to Argentina. In the United States, they are quite common in the southwest. Their habitats are varied, as they can live in plains, deserts, and mountain habitats. More often than not, however, rattlesnakes reside in rocky environments, as rocks help them to find cover and food. Since they are reptiles and ectothermic, these areas also help them with temperature control; depending on the temperature, they bask in the sun on top of the rocks or cool down in the shade under the rocks. Some species enter a hibernation-like state during winter.

Diet and Behavior

Rattlesnakes are carnivores. They eat a variety of small prey like mice, rats, and other small rodents, as well as smaller species of birds. Rattlesnakes are stealthy hunter. They lie in wait for their prey, then strike with their venomous fangs to immobilize the prey. Once the prey is dead, the rattlesnake will swallow it head first. Due to the snake's digestion process, a rattlesnake will sometimes seek out a place to rest while their meal is being digested.

Reproduction and Offspring

In the United States, most rattlesnakes breed in June through August. Males have sex organs called hemipenes at the base of their tails. Hemipenes are retracted when not in use. Females have the ability to store sperm for long periods of time, so reproduction can occur well after mating season. The gestation period varies based on species, with some periods lasting for almost 6 months. Rattlesnakes are ovoviviparous, which means that that eggs are carried inside the mother but the young are born live.

Offspring numbers vary based on species, but typically range from 5 to 20 young. Females usually only reproduce once every two to three years. Newborns have both functioning venom glands and fangs at birth. The young do not stay with their mother long and are off to fend for themselves shortly after being born. 

Conservation Status

Most species of rattlesnake are classified as "least concern" by the International Union for Conservation of Nature and Natural Resources (IUCN). However, most rattlesnake species are decreasing in population size, and a few species, such as the Santa Catalina Island rattlesnake (Crotalus catalinensis) are classified as "critically endangered." Predation as well as human encroachment on habitats are the two most prevalent threats to rattlesnake populations.

Species

There are over thirty species of rattlesnakes. Common species are the eastern diamondback, timber rattlesnake, and the western diamondback rattlesnake. Timbers can be more passive than other species. Eastern diamondbacks have the distinctive diamond pattern that helps them to blend into their environment. The western diamondback is usually the longest of the rattlesnake species.

Rattlesnake Bites and Humans

Thousands of people are bitten by snakes in the United States each year. While rattlesnakes are usually passive, they will bite if provoked or startled. Snakes bites are rarely fatal when the proper medical care is sought. Common symptoms from a snake bite can include swelling at the bite site, pain, weakness, and sometimes nausea or excessive perspiration. Medical care should be sought immediately after a bite.

Sources

  • “11 North American Rattlesnakes.” Reptiles Magazine, www.reptilesmagazine.com/11-North-American-Rattlesnakes/.
  • “Frequently Asked Questions About Venomous Snakes.” Venomous Snake FAQs, ufwildlife.ifas.ufl.edu/venomous_snake_faqs.shtml.
  • “The IUCN Red List of Threatened Species.” IUCN Red List of Threatened Species, www.iucnredlist.org/species/64314/12764544.
  • Wallach, Van. “Rattlesnake.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 8 Oct. 2018, www.britannica.com/animal/rattlesnake.