Snakes and lizards are grouped together in the order Squamata, which is derived from the Latin
word squamatus, meaning scaly.
Although they have been successful at dominating the terrestrial scene, aquatic squamatans are relatively rare and most are snakes. The Hydrophiidae are venomous marine snakes which are entirely aquatic, with oarlike tails and flattened bodies for swimming. One species, Astrokia stokesii of Australia, has a powerful bite which can penetrate a wetsuit, injecting a potentially deadly neurotoxin!
While a snake's shape is somewhat hydrodynamic, a lizard's is not. With their short, stubby legs,
lizards are not efficient swimmers. However, there are always exceptions in nature! The marine
iguana of the Galapagos Islands is the worlds only marine lizard. It evolved a paddle-like
swimming tail in order to venture into the ocean for food, when none remained on land. It
recovers from its brief forays into the cold ocean by basking on the black lava rocks along the
Basilisk lizards are sometimes known as 'Jesus lizards' because of their unique ability, with the aid of special scales on their feet, to escape danger by sprinting across the surface of water!
In Canada, there are a few aquatic and semi-aquatic snakes including the northern water snake, the queen snake and garter snakes. You can read about these species in the species account section of this website!