section 3 – identifying ontario`s eastern massasauga rattlesnake and

Transcription

section 3 – identifying ontario`s eastern massasauga rattlesnake and
SECTION 3 – IDENTIFYING
ONTARIO’S EASTERN MASSASAUGA
RATTLESNAKE AND ITS LOOK-ALIKES
Ontario has a greater variety of snake species than any other province in Canada.
The province is home to 17 species of snakes, varying in form, habit, habitat and
range. With such a variety of snakes at hand, the province’s scientists
and residents have the opportunity to gather a wealth of information on
snake biology. By learning how to identify snakes and other wildlife,
people can help guarantee the protection of threatened species like
the eastern massasauga rattlesnake.
Stewardship Quote
The eastern massasauga rattlesnake.
“Those who dwell, as scientists or laymen, among the beauties and
mysteries of the earth are never alone or weary of life. Whatever
the vexations or concerns of their personal lives, their thoughts can
find paths that lead to inner contentment and to renewed excitement in living. Those who contemplate the beauty of the earth find
reserves of strength that will endure as long as life lasts.”
– Rachel Carson
TELLING THE SNAKES APART
KNOWING WHICH SNAKE IS WHICH
One of the first steps in massasauga conservation is learning how to identify the
rattlesnake. To do so requires that one learn how to identify other snakes sharing
the same range as the rattlesnake.
The eastern massasauga rattlesnake has similarities with four of Ontario’s nonvenomous snakes. The remaining 12 Ontario snake species are either striped or
without pattern, and are thus not discussed in this booklet.
THINGS TO CONSIDER WHEN YOU SEE A SNAKE:
• the snake’s pattern: striped, blotches, or without pattern?
• Is the tail pointed or blunt at the end?
• What colour is the skin?
• Is the skin rough or smooth?
• How big is the snake?
If it is an adult snake with blotches or bands, then you know it must be one of the
five species in Ontario with such markings: eastern massasauga rattlesnake,
eastern fox, eastern milk, northern water, or eastern hognose snake.
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Note: Newly hatched or young black rat snakes and blue racers
have a bold pattern of blotches. Consult the Toronto Zoo’s
snake identifier, or a field guide, for more information.
SIMILAR , BUT NOT THE SAME
• northern water, eastern hognose, eastern milk, and eastern fox
snakes all resemble a massasauga rattlesnake because of a
blotchy pattern along their bodies;
• eastern fox, black rat and eastern milk snakes will often vibrate the
end of their tail against leaves, simulating the sound made by
a rattlesnake;
• northern water, eastern hognose, eastern milk, and eastern fox
snakes will put on shows of strength or aggression, but are
non-venomous. The massasauga is the only venomous rattlesnake
in Ontario.
EASTERN MASSASAUGA RATTLESNAKE
Sistrurus catenatus catenatus
From sistrum = a rattle and oura = tail, in reference to the rattle at the
tip of the tail
From catenatus= chained, which describes the pattern on the back.
MASSASAUGA IS THE CHIPPEWA WORD FOR GREAT
RIVER -MOUTH AND DESCRIBES THE LOCATION WHERE THE
SNAKE WAS FOUND IN MARSHES ALONG RIVERS.
The heads, bodies and tails of three Ontario
snakes: The Eastern Milk Snake (Left),
The Eastern Massasauga Rattlesnake (Middle),
and The Eastern Fox snake (Right).
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MASSASAUGAS BY SIGHT
The vertical pupil enhances the massasauga’s
night vision, and the heat sensing pit helps it
find prey. Protective keeled scales give the
massasauga a rough appearance
• The massasauga’s most distinguishing feature is the rattle at the
end of its blunt tail. The rattle sets this species apart from all other
snakes in Ontario (although on some individuals it goes missing
due to wear or confrontations with predators). When the snake
vibrates its tail, interconnected segments of the rattle produce an
insect-like buzz;
• The massasauga is the only snake in Ontario that has vertical
(cat-like) eye pupils;
• A heat sensitive pit on each side of the head, between the nostril and
eye, allows the massasauga to detect small changes in temperature,
and to find warm-blooded prey such as mice and voles;
• The massasauga’s scales are keeled, which means that the scales
have a raised ridge along their mid-line, giving the snake a rough,
textured appearance.
WHAT TO LOOK FOR :
• Length: 47-76 cm;
• Colour: brownish grey to dark grey background with dark
saddle-shaped blotches along the body;
The rattle at the end of the massasaugas blunt tail.
• Underbelly colour: black with light markings;
• Head: diamond shaped with white stripes along jaw;
• Eyes: large with vertical pupils;
• Scales: keeled, anal scale single;
• Tail: stubby with brown, segmented rattle;
• Reproduction: give birth to 6-20 live young;
• Young: lighter in body colour with cream-coloured button
on the tip of the tail;
• Habitat: wet prairies, bogs, swamps, rocky areas and
dry woodlands;
• Status: threatened in Ontario;
• General Info: rattlesnakes will not always rattle. Often they
will sit motionless, avoiding detection, until the predator or
human leaves.
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BABY RATTLERS!
Juvenile or young rattlesnakes are generally well patterned and
lighter in colour than the adults. They are born with a single cream
to yellow coloured segment called a “button” rather than a rattle
with several segments. Each time the snake sheds its skin, a
segment is added to the rattle. Juveniles are born with venom
and functional fangs.
When born, the massasauga has only a cream to
yellow segment (button) at the end of the tail.
“LOOK ALIKE” SNAKES: KNOWING THE DIFFERENCE
EASTERN FOX SNAKE
Elaphe gloydi
The eastern fox snake is a relatively large snake that
inhabits the same areas as the eastern massasauga.
Adult fox snakes often have a rusty-copper
coloured head.
The fox snake, as seen here, has a slender tail.
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WHAT TO LOOK FOR :
• Length: 91-137 cm;
• Colour: the snake is characteristically yellow-brown in colour with
large brown or black blotches on its back that alternate with smaller
blotches along its sides;
• Underbelly Colour: yellow with black checkerboard pattern;
• Head: oval shaped and often rusty-copper in colour;
• Eyes: rounded pupils;
• Scales: weakly keeled; anal scale divided;
The yellow with black “checkerboard” pattern
on the underside of the eastern fox snake.
• Tail: pointed. A fox snake may vibrate its tail against leaves or
grass, making a buzzing sound, which mimics the sound of a rattling
massasauga. Fox snakes are NOT rattlesnakes and are not
venomous;
• Reproduction: females lay 10-12 eggs in early summer, which
hatch in late summer;
• Young: young snakes are yellowish-grey with brown blotches;
• Habitat: fox snakes prefer woodland edges, shrubby fields, and wetlands;
• Status: threatened in Ontario;
• General Info: Due to its pattern and tendency to vibrate its pointed tail when
disturbed, eastern fox snakes are more commonly mistaken for the massasauga
than any other snake. However, the fox snake is non-venomous. Eastern fox
snakes range only within the Great Lakes Basin and feed mainly on rodents, birds
and bird eggs. It is often known as a “hardwood rattler” or “copperhead,” though
neither name is appropriate: it is neither a rattlesnake nor a copperhead (the name
of a snake in the U.S.).
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EASTERN MILK SNAKE
Lampropeltis triangulum triangulum
Eastern milk snake, pictured here with four eggs.
The underside of the eastern milk snake, showing
checkerboard pattern.
WHAT TO LOOK FOR :
• Length: 61-90 cm.
• Colour: cream, tan, or light grey with red or dark brown blackbordered blotches alternating with blotches along each side.
A white blotch on neck often appears Y or V shaped;
• Underbelly Colour: whitish belly with black checker-board pattern;
• Head: slender and oval in shape;
• Eyes: rounded pupils;
• Scales: smooth scales; anal scale single;
• Tail: pointed, slender tail, vibrates tail when frightened;
The eastern milk snake showing the y or
v shape on the back of the neck.
• Reproduction: lays eggs;
• Young: young have bright red-brown blotches bordered in black;
• Habitat: fields, woodlands, rocky hillsides, river bottoms;
• Status: common in many parts of Ontario;
• General Info: Because of its colour, pattern and tendency to vibrate
its pointed tail when disturbed it is commonly mistaken for the
massasauga. It is non-venomous and secretive; often found in
search of rodents around old buildings.
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NORTHERN WATER SNAKE
Nerodia sipedon sipedon
The northern water snake, although
sometimes temperamental, is non-venomous.
WHAT TO LOOK FOR :
• Length: 61-106 cm;
• Colour: well patterned individuals have reddish brown squarish
blotches down the back with row of alternating blotches along each
side. At the front of the body, some blotches extend as saddles over
the back and onto the sides. Patterns on older individuals may be
obscured and appear black or brown;
• Underbelly Colour: belly cream with irregular rows of reddish half
moon crescents;
• Head: oval head;
• Eyes: rounded pupils;
The northern water snake will quickly flee
into water when threatened.
• Scales: keeled; anal scale divided;
• Tail: pointed;
• Reproduction: gives birth to live young;
• Young: usually more brightly patterned than the adults;
• Habitat: in or near water areas such as ponds, lakes, rivers, streams and ditches;
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• Status: common in many parts of Ontario;
• General Info: will flee from humans; will investigate splashing objects
in the water in hopes of finding prey. The northern water snake is
non-venomous and feeds mainly on fish and frogs.
EASTERN HOGNOSE SNAKE
The northern water snake preys on fish,
frogs and tadpoles.
Heterodon platirhinos
WHAT TO LOOK FOR :
The eastern hognose snake can be found to
have very little pattern.
• Length: 51-84 cm;
• Colour: large dark blotches, alternating with smaller blotches along
the sides against a brown-grey body, can be blotched or plain grey,
green-brown or even black;
• Underbelly Colour: belly yellow and sometimes with greenish
grey pattern;
• Head: flat head with distinctive upturned snout;
• Eyes: rounded pupils;
• Scales: keeled; anal scale divided;
Eastern hognose snake “playing dead” to
discourage predators.
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• Tail: pointed and often in a tight flat coil; underside of tail is lighter in
colour than body;
• Reproduction: lays eggs in logs, wood piles, and sandy areas;
• Young: young are more brightly patterned than adults, often with a
black underside;
• Habitat: sandy areas are a favourite habitat where they will seek out
toads for food;
• Status: vulnerable in Ontario;
• General Info: when threatened, the snake may show various
harmless displays: spreads its neck, hisses loudly, lifts its head,
attempts closed mouth strikes, and, if all else fails, rolls over and
plays dead; it is not a threat but very showy. It is also known as a
“spreading” or “hissing adder” due to its behaviour. Remember –
this is a display only and the snake is harmless. It is a specialized
predator of toads.
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COMPARE THE MASSASAUGA TO THESE LOOK-ALIKE SPECIES. EXAMINE
THEIR DIFFERENCES AND TEST YOUR KNOWLEDGE. ANSWERS ON THE
REVERSE SIDE.
Eastern Massasauga Rattlesnake.
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