Hibernacula, hibernaculum, hibernation site, overwintering site,
refugia, den

All of these words are used to describe the places where many
snakes spend the cold months of the winter and at times, the
extreme heat of summer. Hibernacula can range in form from
natural structures such as caves and sinkholes to man-made
structures such as foundations, crawl spaces and garages.
Although seemingly very different, these structures have one thing
in common; they provide a thermally stable place for snakes to hide
while the temperatures are too extreme for activity.

Because they are ectothermic animals, snakes are vulnerable to
excessive temperatures, both hot and cold. When the temperature
reaches levels outside the snakes' comfort zone, its response is to
seek shelter. In the fall, when temperatures start to drop, most
people refer to this behavior as hibernation.
In August of 2006, members of The Ohio Division of Parks
and Team Snake constructed two artificial hibernation
structures for the Lake Erie Water Snake at the Middle
Bass Island State Park.
These structures will hopefully provide hibernation
habitat for LEWS and other snake species residing within
the park and marina. The hibernacula are just a portion of
the beneficial aspects for LEWS the ODNR has included
within their plans for development.
So just how does one build a snake “hibernacula”?
The MBISP hibernacula were modeled after similar
structures built in southern New Jersey by other snake
researchers, but with a few modifications.
Construction begins by digging a hole approximately 6’ deep
and 10’ x 10’ in size. Large rocks are placed at the bottom
of the hole to create crevices that the snakes can utilize.
Several pieces of flexible drain pipe fitted with “T”
shaped pieces at the terminal ends are placed among the
rocks within the structure providing entrance. The pipes
also had 2” holes cut into the sides along the entire length
of the pipe to provide snakes multi-level access.
More large rocks, small logs and left over pieces of drain
pipe are carefully placed and piled creating a multi-layered
shelter. In the case of the MBISP hibernacula, recycled
pieces of concrete were also used from an old septic tank
the park had planned to remove.
Smaller rock rubble is then piled on top and a piece of
filter fabric is laid over the structure. The fabric is
covered with approximately 2-3’ of sand and dirt while
leaving the ends of the flexible pipes uncovered. As a final
step, the entrances are surrounded with more pieces of
small rock to reduce erosion.

here to see how it was done

In late October, after the snakes have moved to where
they plan on spending their winter, the hibernacula will be
surrounded with a “snake barrier” made of silt fencing and
small snake traps. As snakes begin to emerge from
hibernation in the spring of 2007, the structures will be
monitored to determine whether any snakes have
successfully spent the winter within the hibernacula.
Special thanks to those who helped in the planning and
construction of these unique structures.
Watch this site for updates on their future success!
Creating artificial hibernacula is one way of
enhancing LEWS habitat to offset any
damage from development activities. Ohio
Edison and the crew of Durocher
Marine/Kokosing Construction created this
hibernaculum along a south facing slope on
South Bass Island. Thanks to Kim Harpel
from Ohio Edison; Bill Wenger, Stan Neff
and project Manager Tim Paquette of
Durocher Marine; and the Kokosing
construction crew Brice Shepard, Bart
Winand, Rob Hines and Jay Overholt.

here to see how it was done
Metro Toronto
See what others have done to create
artificial snake habitats:
Animal Planet: Backyard
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