Aestivate
Become dormant because of heat or dryness. Some turtles will avoid high temperatures by submerging in the bottom of water, remaining there for days.

Alligator Lizard
One of the three Families of lizards that occur in Canada. This is a small group, consisting of less than 100 species, but they occur in the Americas, Europe and Asia. There is only one species found in Canada, the Northern Alligator Lizard.

Boa
One of the three Families of snakes found in Canada. The Boa Family includes some of the largest snakes in the world, including the Anaconda (Eunectes murinus) and the Reticulate Python (Python reticulatus), both of which can reach 10 m in length. Boas are generally constrictors that swallow their prey whole. There is only one species found in Canada, the Rubber Boa, which is less than 1 m long.

Carapace
Turtles have both a top and bottom shell. The top shell is the carapace while the bottom is called the plastron.

COSEWIC
COSEWIC stands for the Committee on the Status of Endangered Wildlife in Canada. It is the national body which designates species at risk in Canada. Species that are at risk are given one of three designations:

Endangered -- threatened with imminent extinction or extirpation throughout all or a significant portion of its Canadian range

Threatened -- likely to become endangered if the factors affecting its vulnerability do not become reversed

Vulnerable -- at risk because of low or declining numbers, occurrence at the fringe of its range or in restricted areas, or for some other reason, but is not Threatened

COSSARO
The Committee on the Status of Species at Risk in Ontario designates the conservation risk faced by species within the province of Ontario.

Hinge
Some turtles have a transverse hinge along the middle of the plastron allowing them to pivot the plastron. This allows the turtles to partially or completely enclose the head and limbs.

Keel
A raised ridge along a scale or scute. Some snakes and lizards have keels along their scales, while others have smooth scales. Some turtles have a keel down the centre of their carapace.

Leatherback Sea Turtle
One of the six Families of turtles that occurs in Canada. This Family contains only a single species, the Leatherback. As its names suggests it does not possess a hard shell, instead the carapace is covered with a leathery skin.

Lizards
Lizards are a Suborder of Squamata, which is one of the four Orders of reptiles. Although lizards are the least diverse group of reptiles in Canada, worldwide they are the most diverse group with approximately 4 000 species. They range in size from less than 50 mm long to the mighty Komodo Dragon (Varanus komodoensis), which can reach roughly 3 m in total length. The largest species in Canada is the Northern Alligator Lizard which can reach 25 cm in length.

Marine Turtle
One of the six Families of turtles found in Canada. This group includes all the hard-shelled sea turtles. In general they range widely in the warmer marine waters. There are three species which wander into Canadian waters.

Musk and Mud Turtles
This group is one of the six Families of turtles found in Canada. These turtles tend to be fairly small and have a hinged plastron. The only species found as far north as Canada is the Common Musk Turtle.

Plastron
Turtles have both a top and bottom shell. The bottom shell is the plastron, while the top shell is the carapace.

Pond and Marsh Turtles
One of the six Families of turtles found in Canada. This is the largest group of turtles in the world, with approximately 100 species. The group is quite diverse but typically has a low arch to the carapace and a large plastron. Five of Canada's 12 species of turtles belong to this Family.

Scute
The skin covering the bones of a turtle's shell form hard scale- like scutes. The scutes add new material as the turtle grows, hence growth lines can be seen in many scutes. Unfortunately such growth lines only provide a crude estimate of the turtle's age because turtles (especially adults) do not grow every year and old growth lines may become faint or completely worn away.

Short-horned Lizard
One of the three Families of lizards that occur in Canada. This group of lizards contains over 100 species. Some authorities consider this Family to be part of the Iguana Family. There are two species found in Canada, both in the west.

Skink
One of the three Families of lizards found in Canada. Skinks are a large, diverse group consisting of over 1000 species. In Canada, all three species look similar: they have a series of longitudinal stripes, have sleek, smooth bodies and the juveniles have bright blue tails.

Snakes
The snakes are considered a Suborder of Squamata, which is one of the four Orders of reptiles. While all snakes are superficially similar in body shape, they differ markedly in anatomy. In total there are roughly 2 500 species of snakes around the world. Snakes as a group are unusual in that every single species is carnivorous. Snakes range in size from only 10 cm in length to over 10 m! The largest species in Canada is the Rat Snake, which can reach 2.5 m in total length.

Snapping Turtle
One of the six Families of turtles found in Canada. There are only two species in this small group. Snapping turtles have a hooked upper jaw, well-developed claws and a long saw-toothed tail. The only species in Canada is the Common Snapping Turtle.

Softshell Turtle
One of the six Families of turtles found in Canada. As the name suggests, these turtles do no have a hard shell, rather the carapace is covered with a leathery skin. Softshell turtles commonly have a long neck and a long, tubular snout. There is only one species found in Canada, the Spiny Softshell Turtle.

Squamata
One of the four Orders of reptiles. The only other Order found in Canada is Testudines (the turtles). The other two Orders are Crocodylia (the crocodiles and alligators) and Rhynchocephalia (represented by a single lizard-like species from New Zealand, the Tuatara). Squamata includes both the lizards and the snakes, because the two groups are closely related. One can think of snakes as a highly specialized group of lizards with no legs. There are also some reptiles with no legs that are consider lizards rather than snakes because of the greater similarity to most lizards. Some authorities consider snakes and lizards distinct enough to each be a separate Order. In total there are over 6 000 species of snakes and lizards around the world.

Testudines
One of the four Orders of reptiles, only two of which (Squamata and Testudines) are found in Canada. The other two Orders are Crocodylia (the crocodiles and alligators) and Rhynchocephalia (represented by a single lizard-like species from New Zealand, the Tuatara). This group includes all turtles, from small pond turtles barely 10 cm long to mammoth sea turtles almost 2 m in length. Testudines is a comparatively small group of organisms with just over 250 species worldwide. Despite this they occur in most ecosystems, from deserts to oceans.

Typical Snake
One of the three Families of snakes that occur in Canada. The typical snakes, or Colubrids, contain the majority of snake species in the world, approximately 1500. All of the snakes in Canada except for the Rubber Boa and the rattlesnakes belong to this Family.

Viper
One of the three Families of snakes found in Canada. All Vipers are poisonous. They include the rattlesnakes (the only poisonous snakes that occur in Canada), as well as the copperheads and cottonmouths, which do not occur in Canada. Not all poisonous snakes belong to this Family. Cobras, for example, belong to the Elapid Family. There are three species of Viper known from Canada.