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. 26 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). 27 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. 28 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. 29 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.). 30 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. 31 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; 32 • 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. 33 • 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. 34 COMPARE THE MASSASAUGA TO THESE LOOK-ALIKE SPECIES. EXAMINE THEIR DIFFERENCES AND TEST YOUR KNOWLEDGE. ANSWERS ON THE REVERSE SIDE. Eastern Massasauga Rattlesnake. ??? ??? ??? ??? 35