Sistrurus catenatus edwardsii
Encyclopedia
- Common names: desert massasauga, Edward's massasauga, Edward's rattlesnake.
Sistrurus catenatus edwardsii is a venomous snake
Venomous snake
"Poisonous snake" redirects here. For true poisonous snakes, see Rhabdophis.Venomous snakes are snakes which have venom glands and specialized teeth for the injection of venom...
pitviper
Crotalinae
The Crotalinae, commonly known as "pit vipers" or crotaline snakes, are a subfamily of venomous vipers found in Asia and the Americas. They are distinguished by the presence of a heat-sensing pit organ located between the eye and the nostril on either side of the head...
subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
found in the southwestern United States
Southwestern United States
The Southwestern United States is a region defined in different ways by different sources. Broad definitions include nearly a quarter of the United States, including Arizona, California, Colorado, Nevada, New Mexico, Oklahoma, Texas and Utah...
and northern Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. In places its range overlaps that of S. c. tergeminus
Sistrurus catenatus tergeminus
Sistrurus catenatus tergeminus is a venomous pitviper subspecies found in the southwestern plains of the United States. In some areas its range overlaps that of another subspecies, S. c. edwardsii, and intergrading of the two is not unknown....
) and intergrading of the two subspecies is not unknown.
Description
Sistrurus catenatus tergeminus
Sistrurus catenatus tergeminus is a venomous pitviper subspecies found in the southwestern plains of the United States. In some areas its range overlaps that of another subspecies, S. c. edwardsii, and intergrading of the two is not unknown....
, reaching a maximum length of 53 cm.
The color pattern consists of a light gray or white base color, with dark gray or gray-brown blotches. They have a distinctive, dark stripe that runs along the side of the head which passes over the eye. Their rattles are significantly higher pitched than those of larger species of rattlesnake, sometimes giving them the nickname buzztail.
Compared to S. c. tergeminus, it is paler in color and its belly is nearly white. Midbody, it has 23 rows of dorsal scales
Dorsal scales
In snakes, the dorsal scales are the longitudinal series of plates that encircle the body, but do not include the ventral scales.When counting dorsal scales, numbers are often given for three points along the body, for example 19:21:17...
instead of 25, as well as fewer ventral scales
Ventral scales
In snakes, the ventral scales are the enlarged and transversely elongated scales that extend down the underside of the body from the neck to the anal scale. When counting them, the first is the anteriormost ventral scale that contacts the paraventral row of dorsal scales on either side...
and dorsal blotches.
Geographic range
Found in the United StatesUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
extreme southeastern Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
, central and southern New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
, western Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
about as far north and east as the Colorado River
Colorado River (Texas)
The Colorado River is a river that runs through the U.S. state of Texas; it should not be confused with the much longer Colorado River which flows from Colorado into the Gulf of California....
, in the Rio Grande Valley
Rio Grande Valley
The Rio Grande Valley or the Lower Rio Grande Valley, informally called The Valley, is an area located in the southernmost tip of South Texas...
, in many of the Gulf Coast counties about as far north as Brazoria
Brazoria County, Texas
Brazoria County[p] is a county in the U.S. state of Texas, located on the Gulf Coast within the Houston–Sugar Land–Baytown metropolitan area. Regionally, parts of the county are within the extreme southern-most fringe of the regions locally known as Southeast Texas. Brazoria County is among a...
, and on several barrier islands including North Padre Island
Padre Island
Padre Island is part of the U.S. state of Texas. The island is located on Texas' southern coast of the Gulf of Mexico and is famous for its white sandy beaches at the south end...
, Matagorda Island
Matagorda Island
Matagorda Island, Spanish for "thick brush," is a 38 mile long barrier island on the Texas Gulf coast, about seven miles south of Port O'Connor, in the southernmost part of Calhoun County. The island is oriented generally northeast-southwest, with the Gulf of Mexico on the east and south, and...
and San José Island. In addition, isolated populations have been reported in northeastern Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. The type locality is listed as "Tamaulipas ... S. Bank of Rio Grande ... Sonora."
Habitat
Primarily found in rocky, semi-arid and arid areas. According to Conant (1975), it is mostly found in desert grasslands.Behavior
They are primarily nocturnalNocturnal animal
Nocturnality is an animal behavior characterized by activity during the night and sleeping during the day. The common adjective is "nocturnal"....
, especially during the summer months when it is too hot for them to be active, but they will sometimes be found out sunning themselves.
Feeding
Their dietDiet (nutrition)
In nutrition, diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat. With the word diet, it is often implied the use of specific intake of nutrition for health or weight-management...
consists primarily of rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
s, lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
s and frog
Frog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...
s.
Venom
Drop for drop, Massasauga venom is more potent than that of many larger species of rattlesnake, but due to the lower yield (the amount it is capable of delivering in a single bite) its potential for harm is greatly reduced. They are not considered to be deadly, but the venom is a powerful hemotoxinHemotoxin
Hemotoxins, haemotoxins or hematotoxins are toxins that destroy red blood cells , disrupt blood clotting, and/or cause organ degeneration and generalized tissue damage. The term hemotoxin is to some degree a misnomer since toxins that damage the blood also damage other tissues...
which can cause swelling, necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
, and severe pain. Medical treatment should be sought immediately for any venomous snake
Venomous snake
"Poisonous snake" redirects here. For true poisonous snakes, see Rhabdophis.Venomous snakes are snakes which have venom glands and specialized teeth for the injection of venom...
bite. The antivenin
Antivenin
Antivenom is a biological product used in the treatment of venomous bites or stings. Antivenom is created by milking venom from the desired snake, spider or insect. The venom is then diluted and injected into a horse, sheep or goat...
CroFab
CroFab
CroFab is the commercial name for a Crotalidae Polyvalent Immune Fab snake antivenom, indicated for minimal or moderate North American Crotalid snake envenomation. It is developed and manufactured by BTG plc , and distributed in the US by Nycomed Inc...
, while not type specific, can be used to treat severe envenomations from Massasauga rattlesnakes.
Conservation status
The Desert Massasauga is listed as a species of concern in Colorado, due to its limited range in the state, and it is protected by Arizona state law. It is listed as a sensitive species by the United States Forest ServiceUnited States Forest Service
The United States Forest Service is an agency of the United States Department of Agriculture that administers the nation's 155 national forests and 20 national grasslands, which encompass...
.
External links
- Sistrurus catenatus at Herps of Texas. Accessed 31 January 2007.
- Sistrurus catenatus (edwardsii) at Arizona Parc. Accessed 25 August 2007.
- Sistrurus catenatus edwardsii at California Reptiles and Amphibians. Accessed 25 August 2007.