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Deep snow can serve to insulate the
hibernacula during the winter months.

THREATS TO THE HIBERNACULUM

The hibernacula are not easy to identify, and are susceptible to inadvertent destruction in the course of development projects. Hibernation sites may be destroyed by excavation, burial, or flooding. Since eastern massasauga rattlesnakes typically hibernate in water-saturated soils, hibernation sites may also be adversely affected by drainage. However, too little is known about the physical conditions within rattlesnake
hibernacula to predict how development might affect a site’s integrity. Conceivably, even the removal of several trees could sufficiently alter local soil moisture conditions to affect nearby hibernacula.

The destruction of hibernation sites in the winter would obviously result in the death of its occupants. However, because the snakes use the sites repeatedly (known as site fidelity), individuals whose over-wintering sites are destroyed during the summer (when the site is not occupied) would also be likely to suffer mortality. Scientists suspect that massasaugas will search for their destroyed hibernaculum even to the point of being killed by cold temperatures.

EMERGENCE
As spring approaches, the air and ground surrounding the outside of the hibernaculum begins to warm. This temperature increase will slowly cause the inside of the chamber to warm, usually in late April. The snake will slowly move closer to the entrance as the days continue to get warmer. The snake’s metabolism will increase and, in turn, alertness, heart rate, and intake of oxygen will return to normal. As a precaution, massasaugas remain near the hibernaculum to bask, until the
threat of snow or cold weather is eliminated. In May, the snake moves back to its summer habitat.

GENETIC DIVERSITY

For several years, researchers have been collecting blood samples from eastern massasauga rattlesnakes in order to gain knowledge about the species’ genetic
diversity and population structure.

To date, the research has revealed that a great deal of structure exists between the
populations and sub-populations: neighbouring populations are quite distinct from
one another. Scientists have not yet discovered the cause of this peculiarity. The
massasauga has a high degree of site fidelity, returning to the same hibernaculum
and gestation sites. They are also sit-and-wait predators. This combination of traits
makes their home range requirements smaller and lessens the need to disperse
great distances. As a result, genetic mixing may be limited.

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