It is the national body which designates species at risk in Canada. 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. The largest species in Canada is the Northern Alligator Lizard which can reach 25 cm in length.