Eastern massasauga
The massasauga (Sistrurus catenatus) is a venomous rattlesnake species found in midwestern North America. Like all rattlesnakes, it belongs to the pit viper family. Rattlesnakes receive their name from the rattle located at the end of their tails, which makes a loud rattling noise when vibrated which deters predators or serves as a warning to passers-by. Rattlesnakes are the leading contributor to snakebite injuries in North America, but rarely bite unless provoked or threatened.
Massasaugas are grey or tan in color with a row of large rounded brown/black blotches or spots down the center of the back and three smaller rows of alternating spots down each side. Solid black melanistic examples are also known, as well as cases where the back blotches join with those on the sides. Young massasaugas are well-patterned but paler than adults. These snakes have heat-sensing pits on each side of their smallish head and their scales are keeled.
Massasaugas are found in North America from Ontario, Canada, and western New York southwest to southeastern Arizona in the United States and northern Tamaulipas, Mexico. In Mexico, isolated populations exist in southern Nuevo León, north-central Coahuila, and Samalayuca, Chihuahua. These rattlesnakes live in various habitats ranging from swamps, bogs, sedge meadows, wet prairies, and marshes to grasslands and forests. In the western part of their range, massasaugas can be found in rocky hillsides, wetlands, scrub plains, desert grassland, and dry prairie.
Massasaugas are diurnal and lead solitary life. During hot summer months, they are usually active early morning and late evening trying to avoid the heat of the day. Massasaugas stay active from April till late October and hibernate during winter in small abandoned burrows of other small animals. These rattlesnakes are very good swimmers and can even hunt their prey in the water. They detect prey with the sense of smell and with the help of heat-sensitive pits located on their faces. They can also feel vibrations and have good eyesight. When threatened, massasaugas will warn or show aggression by rattling their tail, coiling up, and unexpectedly striking.
The venom of this species is a cytotoxic venom, so destroys tissue. It also contains specialized digestive enzymes that disrupt blood flow and prevent blood clotting. Severe internal bleeding causes the death of the small animals that this snake eats. After envenomation, the rattlesnake is able to withdraw from the dangers of sharp-toothed prey animals until they are subdued and even partially digested by the action of the venom. Most massasauga snakebites in Ontario have occurred after people deliberately handled or accidentally stepped on one of these animals. Both of these scenarios can be prevented by avoiding hiking through areas of low visibility (in rattlesnake country) when not wearing shoes and long pants and by leaving the snakes alone if encountered.
Massasaugas are carnivores; they feed on small vertebrates, including mammals, lizards, and other snakes, as well as invertebrates such as centipedes. Adults feed mainly on rodents, while juveniles usually prey on reptiles: more often lizards in western populations and snakes in eastern ones.
The breeding season for massasaugas begins in the spring and can also occur in the fall. When females are ready to mate they shed their old skin and release pheromones that attract males. Females give birth to 5-20 live young usually in abandoned mammal burrows or fallen logs. The gestation period lasts around 3.5 months. Snakelets are born fully developed and stay around their mother for a few days; after that, they disperse. Young Massasaugas become reproductively mature and ready to mate at 3 to 4 years of age.
The biggest threat facing massasaugas is habitat loss. Historically, this has been due to human activity, and more recently primarily from natural forest succession. These snakes are also heavily persecuted because they are considered to be a threat due to their venomous and lethal bite.
The IUCN Red List and other sources don’t provide the number of the massasauga total population size. Currently, this species is classified as Least Concern (LC) on the IUCN Red List.
Massasaugas play a very important role in their ecosystem. Due to their diet habits, these snakes control populations of rodents and other small mammals as well as help control pests in agricultural fields.