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GEOGRAPHIC
RANGE AND HABITAT
This species ranges from Iowa and southeastern Nebraska south
through central Oklahoma into central Texas and the upper Gulf
Coast of Texas. There is also an isolated population in southeastern
Colorado.
This is a rattlesnake of the plains and grasslands. Often frequents rocky areas, clumps of Prickly Pear cactus and is not usually found far from a source of water.
In southerly areas or those lacking large rocky retreats, individuals may seek shelter in mammal burrows. Active April to October over much of range, and becomes crepuscular and nocturnal during hot summer months.
These snakes will ball and sleep in tangled piles to keep warm but prefer their own den. |
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DESCRIPTION
Massasaugas are stout bodied snakes with a triangular shaped head.
The pupils are vertically elliptical and there is a heat sensitive
pit located between the eye and nostril. This pit is larger and
positioned lower on the face than the nostril. There is a rattle
at the end of the tail. The rattle is comprised of a series of
interlocking keratinous - like segments that make a buzzing noise
when the tail is vibrated. The scales are keeled and the anal
plate is single.
The belly is a mottled grayish-brown, generally with more light
pigment than dark. Like all rattlesnakes of the genus Sistrurus
it has 9 large distinct scale plates on the crown of the head.The
scale count at mid-body is 25. |
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DIET
Massasaugas diets are comprised largely of small mammals, but small birds, lizards, frogs, toads, and other snakes are also consumed. While adults usually feed upon mice, small snakes are an important food item for young massasaugas. It is interesting to note that this snake will bite and release adult mice then search them out and swallow them after they are dead. When birds and lizards are to be consumed, they are held in the snake's jaws until the venom takes effect |
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LIFE CYCLE/SOCIAL
BEHAVIOR
In early spring, the Western Rattlesnake basks
in the sun or glides around as it looks for food and mates. In
dense chaparral, where little sun reaches the ground, it may climb
to the tops of bushes to bask. As the weather warms, it becomes
more active at dusk or at night
Western rattlesnakes are calm snakes that only rarely rattle,
even when approached by potential predators; instead, they prefer
to remain still and avoid being seen or heard. When they do rattle,
the tail vibrations are very fast, involving twitches of 20-100
times per second, depending on the temperature (warm snakes rattle
faster than cool ones).
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REPRODUCTION
Males achieve a larger size than females. During the spring
males leave their hibernation sites and begin searching
for food and mates. Occasionally this leads to an encounter
with another male which often results in a bout of ritualistic
combat. Often time, the two contestants engage in this behavior
under the attention of a nearby female. The males intertwine
the anterior portions of their bodies while spiraling upward.
The victor is determined as the male who forces his opponent
to the ground. This spiraling demonstration often results
in both snakes toppling over and continuing to wrestle on
the ground.
Alas, to the victor goes the spoils. The winner of these
'wrestling matches' usually receives mating privileges with
the nearby female. Courtship involves the male actively
tongue flicking the dorsal surface of the female's body.
As the courtship ensues, the male's head begins to move
to and fro in a jerky yet rhythmic motion. As the courtship
continues, the male aligns his cloaca with the female's.
Should his intentions be undesired, she will shove the male
aside by using an arch of her coils. Females give birth
in late September to early October to 9 to 14 young measuring
9 to 13.5 inches (Tennant, 1998). In some populations, females
only reproduce every other year.
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INTERESTING
FACTS
1. This snake is missing the pigment, melanine, which gives animals much of their coloration. This condition is somewhat of a rarity in rattlesnakes. Albinos born in the wild are at a great disadvantage as they are easily spotted by their natural enemies and are usually killed early in life.
This specimen was captive born at a reptile breeding facility and will live a long life in the protection of the Museum. She may eventually reach a length of over 6 feet and be seen by over one million people in her 20 to 30 years of life.
2. The largest reported measurement for a western
diamondback rattlesnake is 92.5 inches (Jones, 1997). Interestingly
the second largest specimen to be measured was found in Cedar
Hill, Texas and measured 92 inches. (Curtis, 1949). While gigantically
proportioned specimens such as these are unlikely to be found
in the wild. Adults in the wild usually measure 18 to 27 inches.
Size and color vary greatly.
3. Due to its generally mild disposition, nocturnal nature and
its tendency to avoid areas populated by people, this species
accounts for only a few snakebite cases. Due to the moderate toxicity and low delivery yield of it's venom, the chance of a lethal bite to a human is somewhat unlikely. |
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