Fish, Amphibians, Reptiles
Some vertebrates do not need feathers or fur on their bodies to keep warm. That’s because they are ectotherms, or “cold-blooded”. This means that their internal temperature matches that of their environment, which is the case for fish, amphibians and reptiles.
Our country contains about one-quarter of the world’s fresh water. That places a lot of responsibility on Canadians to protect the 230 species of fish that live in the streams, rivers, and lakes. Since all water in Canada eventually flows out to sea, pollutants that enter our streams, ponds, marshes, lakes, or rivers inland will eventually reach the ocean. Even if you live in central Manitoba, you can have an impact on the 400 marine fish species that are found in our coastal water.
Amphibians, represented by frogs and salamanders in Canada, also rely on our freshwater ecosystems to survive. Their eggs do not have hard shells and must be laid in water or in a very humid environment. They do not have scales therefore their skin must remain moist. Most species go through a two-stage life cycle: they hatch into aquatic larvæ (commonly known as tadpoles) which eventually change into air-breathing adults.
Species from two of the four groups, or Orders, of the world’s reptiles are found in Canada: turtles, and lizards and snakes. The scales on their bodies and their hard-shelled eggs make them less reliant on the presence of water, but our turtles need access to both aquatic and terrestrial habitats to complete their life cycle. Snakes and lizards are, for the most part, land-dwellers.
Discover some of our species of fish, amphibians and reptiles in this section!
This species belongs to the salmon family. Both land-locked and anadromous—meaning it spawns in fresh water but spends much of its life at sea—populations were known to occur. However, there is no current evidence that anadromous populations still exist.
The Atlantic whitefish has silvery sides, a silvery-to-white belly, and a dark blue-to-dark green back. The fish has an elongated body and a mouth at the end of its snout rather than under its head. Adult fish range from 18 to 40 cm in length. The Atlantic whitefish’s dorsal fin and forked tail fin are dusky in colour; the lower fins are light. The Atlantic whitefish also has a small, fleshy fin between the dorsal and tail fins, which is typical of members of the salmon family.
Adult coho salmon have silvery sides and metallic blue backs with irregular black spots. Spawning males have bright red sides, and bright green backs and heads, with darker colouration on their bellies. The fish have hooked jaws and sharp teeth. Young coho salmon are aggressive, territorial and often vibrantly coloured, with a large orange anal fin edged in black and white.
Freshwater turtles are reptiles, like snakes, crocodilians and lizards. Like other reptiles, they are ectothermic, or “cold-blooded”, meaning that their internal temperature matches that of their surroundings. They also have a scaly skin, enabling them, as opposed to most amphibians, to live outside of water. Also like many reptile species, turtles lay eggs (they are oviparous). But what makes them different to other reptiles is that turtles have a shell. This shell, composed of a carapace in the back and a plastron on the belly, is made of bony plates. These bones are covered by horny scutes made of keratin (like human fingernails) or leathery skin, depending on the species. All Canadian freshwater turtles can retreat in their shells and hide their entire body except the Common Snapping Turtle (Chelydra serpentina). This shell is considered perhaps the most efficient form of armour in the animal kingdom, as adult turtles are very likely to survive from one year to the next. Indeed, turtles have an impressively long life for such small animals. For example, the Blanding’s Turtle (Emydoidea blandingi) can live for more than 70 years! Most other species can live for more than 20 years.
There are about 320 species of turtles throughout the world, inhabiting a great variety of terrestrial, freshwater and marine ecosystems on every continent except Antarctica and its waters. In Canada, eight native species of freshwater turtles (and four species of marine turtles) can be observed. Another species, the Pacific Pond Turtle (Clemmys marmorata), is now Extirpated, having disappeared from its Canadian range. Also, the Eastern Box Turtle (Terrapene carolina) has either such a small population that it is nearly Extirpated, or the few individuals found in Canada are actually pets released in the wild. More research is needed to know if these turtles are still native individuals. Finally, the Red-eared Slider (Trachemys scripta elegans), has been introduced to Canada as released pets and, thus, is not a native species.
The leatherback seaturtle is the world’s largest reptile. It is significantly larger than all other marine turtles. The leatherback’s body is teardrop-shaped, tapering at the rear to a blunt point. The carapace, or upper shell, can grow to more than 2 m in length, and the turtle can weigh more than 900 kg. Like all sea turtles, the leatherback has both front and rear flippers, but it is the only sea turtle whose flippers have no claws. Its large front flippers are usually at least half as long as its carapace. The leatherback, like other sea turtles, cannot retract its head or flippers under its shell as tortoises and freshwater turtles can.
The leatherback is also the only sea turtle that does not have a hard shell or scales. Instead, its carapace is covered with the leathery skin that gives the turtle its name. The skin covers a thick layer of oil-saturated fat and connective tissue and a matrix of small bony plates that fit together, almost like a jigsaw puzzle, to form the shell. Seven ridges run the length of the turtle’s carapace, which is a dark bluish-black colour. Sometimes the turtle’s carapace appears brown when it is seen in the water. The leatherback’s carapace, neck, head, and front flippers are usually covered with white or bluish-white blotches. Its plastron, or bottom shell, is pinkish-white.
Leatherbacks have a pink patch on the top of the head. Each pink spot, like a human fingerprint, is unique. Scientists are not certain what function the pink spot has, though some think it might help the turtle sense light or determine where it is located in the ocean.
Western Garter Snake
The western garter snake (Thamnophis elegans) is a medium-sized snake with a fairly robust body and long tail. From nose to tip of tail adults can measure between 460-960 mm and females are larger than males.
The head of the western garter snake is large and distinct from its neck. Its crown is black or brownish, depending on which part of western Canada the snake is located. The snake’s upper lip, chin and throat are white or yellow and its eyes are moderately large with a round pupil.
Sometimes the western garter snake is mistaken for the gopher snake or other garter snakes. A standard way to tell the difference between garter snake species is to look at scale patterns. The western garter snake generally has 10 lower lip scales, and eight upper lip scales. Other garter snakes usually have seven scales on the upper lip. Also, the sixth and seventh upper lip scales are usually enlarged (taller than they are wide). At mid-body, this snake has 21 rows of body scales and only a single anal plate. The scales on its back are keeled — ridged instead of smooth.
Colours vary with individual snakes, but the prominent yellow to orange stripe running down the western garter snake’s back is easiest to see. There are two lateral stripes on either side of its body — on the 2nd and 3rd rows of body scales — that are similar in color to the stripe down its back. In the space between stripes, the western garter is marked with dark spots or light specks. Like its head, its body has a grayish-green or black to dark brown colour.
The western garter snake has a grey or beige underbelly colour that may have dark spots, or a dark underbelly with white flecks concentrated down the mid-line.