Family Chelydridae (Snapping turtles)
This family includes two species, both of which occur North America. The alligator snapping turtle lives in the Southern United States and is the largest fresh water turtle in North America, reaching a maximum weight of 113 kg!
Members of this family have big heads, powerful jaws, long tails, and a shield-like carapace. They live in aquatic conditions, feeding on plants and animals. The plastron is reduced, and the bridge between the plastron and carapace is narrow. Members of this family range from Canada to South America.
One species occurs in Canada:
- Common snapping turtle (Chelydra serpentina)
Family Trionychidae (Soft-shelled turtles)
Softshell turtles are a strange group of highly specialized turtles which have been described as "living pancakes". Unlike most turtles, the carapace of a softshell is covered with leathery skin instead of keratinized plates. Their flattened, disc-shaped bodies and the tapered edges of their carapace allow them to blend in almost indistinguishably with the mud bottom of rivers and lakes. Their neck is very long, and the nose terminates in an elongated, pig-like snout. They are extremely shy of humans, and rarely leave the water, only coming on shore to occasionally bask, and once a year to lay eggs.
One species occurs in the Canada:
- Eastern Spiny softshell (Apalone spinifera)
Family Emydidae (Box and Water Turtles)
This is the largest and most diverse of all the turtle families, with 33 genera and about 100 species. Members of this family, which include the box and pond turtles, are present on every continent except Australia and Antarctica. Most species are aquatic, but some are semi-aquatic and a few are terrestrial. All members have small heads, short tails, and well-developed shells. The plastron and carapace are usually united by a broad bony bridge, and the carapace is domed in shape.
Eight species occur in Canada:
- Painted turtle (Chrysemys picta)
- Spotted turtle (Clemmys guttata)
- Wood turtle (Clemmys insculpta)
- Blanding's turtle (Emydoidea blandingii)
- Common map turtle (Graptemys geographica)
- Western pond turtle (Clemmys marmorata)
- Eastern box turtle (Terrapene carolina)
- Red-eared slider (Trachemys scripta)
Family Kinosternidae (Musk and Mud Turtles)
The Kinosternidae are small turtles which are restricted to the New World. There are 4 genera and 23 species in this family. The members of this family have inelegant names, such as stinkpots, stinky jims, and musk turtles. Members of this family derive their name from the musky secretion which they discharge from two glandular openings on each side of the body when they are handled. The two gland openings are situated where the skin meets the underside of the carapace. The bad smell is believed to be a defence against predation.
This group is aquatic, rarely leaving the water except during rain or in the nesting season. Although they are aquatic, they seldom swim but rather walk on the bottom. They bask occasionally, but usually remain partly in the water. Identification is difficult without flipping them over to examine the plastron. They have relatively small plastrons that lack a hinge to the carapace. The small plastron offers little protection for the legs. The jaws are strong, and the necks long and they are known to have short tempers.
One species occurs in Canada:
- Common musk turtle (Sternotherus odoratus)
Family Dermochelyidae (Leatherback turtle)
There is only one species of turtle in this family worldwide. The leatherback sea turtle is the world's largest turtle. The leatherback's shell has smooth, leathery skin and prominent lengthwise ridges. It inhabits deep tropical and subtropical waters, but occasionally occur in as far north as Norway, the British Isles, Labrador and British Columbia. These marine turtles are found further north than any because their large bodies enable them to maintain body temperatures up to 25 OC, even in water that is as much as 18 OC cooler. Their diet consists primarily of jellyfish.
There is only one species of turtle in this family:
- Leatherback sea turtle (Dermochelys coriacea)
Family Cheloniidae (Loggerhead, Green and Atlantic sea turtles)
This family contains six species worldwide, but only three are found in Canada. These are large marine turtles, primarily of tropical and subtropical seas, but they often travel to northern waters to feed. Their shells are low and streamlined and they have powerful flippers tailored for swimming. The loggerhead and Atlantic ridley occur off of Canada's Atlantic coast, but the green sea turtle has also been found in Pacific waters.
Three members of this family are found in Canadian waters:
- Loggerhead turtle (Caretta caretta)
- Atlantic ridley turtle (Lepidochelys kempi)
- Green turtle (Chelonia mydas)
Suborder Lacertilia - lizards
Lizards are the most abundant reptiles in the world with over 3307 recognized species, but are none are aquatic. Although their bodies are similar looking to salamanders, their skin is dry with scales and they have claws on their toes.
Suborder Amphisbaenia - snake-like reptiles
There are 150 species of amphisbaenians, but none occur in Canada. They are snake-like reptiles that have rings of scales encircling the entire body and tail. They have no external ear openings and only a few have visible limbs.
Suborder Serpentes - snakes
There are over 2 300 species of snakes in the world belonging to 12 families. They are widespread, occurring as far north as Scandinavia in the Arctic Circle and south to Australia, Africa and the tip of South America, but are absent in New Zealand. They live at sea level or as high as 4 900 metres in the Himalayan mountains and are found in a variety of habitats, either aquatic or terrestrial. All snakes are scaled and legless, but some possess vestiges of pelvic limb bones. The body organs are elongated and they have many vertebrae (from 141 to 435).
In Canada, there are twenty-four species of snakes, but only ten are found in aquatic habitats. Three of the twelve snake families are represented in Canada.
Known as "typical snakes", there are 303 genera and 1575 species in this family. Most species of snakes belong to this family, and colubrids are found in all parts of the world except Australia. This family include a diverse array of snakes with a wide range of habitats, characteristics and behaviour. These snakes have wide scales, and solid teeth are usually present, with some species having venom glands. Members of this family have varied diets, with some feeding on worms and insects, while larger species eat birds and mammals. This group also have oviparous and viviparous forms.
In Canada, there are twenty species of colubrids, but only eight frequent aquatic habitats:
- Water snake (Nerodia sipedon)
- Queen snake (Regina septemvittata)
- Brown snake (Storeria dekayi)
- Common garter snake (Thamnophis sirtalis)
- Plains garter snake (Thamnophis radix)
- Wandering garter snake (Thamnophis elegans)
- Ribbon snake (Thamnophis sauritis)
- Fox snake (Elaphe vulpina)
In all, there are 18 genera and 58 species of boids worldwide. Members of this family are largely tropical and include the giant Anaconda of South America, the Reticulate Python of Asia and the well known Boa Constrictor of South and Central America. They typically feed on warm blooded animals, coiling and tightening their bodies around their causing rapid suffocation.
In Canada, only the one snake represents this family:
- Rubber boa (Charina bottae)
Most of the dangerously venomous snakes belong in this family, including copperheads, cottonmouths and rattlesnakes. These snakes are unique because they have facial pit organs on each side of the head which enables them to sense the infrared spectrum. The pits helps the snake aim and strike at warm-blooded prey. Rattlesnakes also possess an effective noise-making rattle on the end of their tail.
In Canada there is only one member of the Viperidae family:
- Eastern Massasauga rattlesnake (Sistrurus catenatus)