Arctic Life/Arctic Animals/Invertebrates/Molluscs

From Arctic Bioscan Wiki

Molluscs

Soft, slimy bodies and hard, shelly exteriors are probably the best way to describe the members of this phylum which include snails, slugs, clams, and octopus. While these creatures differ tremendously in size and shape, they share a similar body plan. Molluscs have a curved body, called a mantle, with a flat, muscular area at its bottom known as the foot. Most molluscs secrete a hard shell, made out of calcium, that covers the mantle. Mollusc shells vary in thickness and elaboration, to which any seashell collector can attest. Gills, blood vessels, and the digestive tract are contained within the mantle. Mucous is secreted by glands in the skin of exposed body parts. Muscles in the foot are used for locomotion; they contract in a wave-like motion to pull the animal forward, or to burrow into the sediments.

Relative to other ecosystems, arctic freshwater environments are sparsely populated with molluscs. One suggested reason is that cold water complicates the deposition of calcium, making it difficult for snails and clams to build their shells. Another explanation for the scarcity of molluscs on arctic islands is that, they are not good colonizers. As a result, they simply have not managed to reach many suitable habitats.

We have compiled a list of 8 groups of molluscs which you will most likely encounter in the Canadian Arctic.