Polar Gigantism

Pycnogonids or more commonly known as the Sea Spiders, are marine arthropods that can be found across all oceans. Like the common house spider, they are very small and can grow to about 3 millimeters or about 1/8 on an inch.

However, the Antarctic Sea Spider can grow to lengths of about 15 centimeters with a leg span of about 40 centimeters. You must be thinking, why the Antarctic Sea Spider is bigger than its relatives that live elsewhere. This is where Polar Gigantism comes into play.

Polar Gigantism refers to the tendency of marine invertebrates to grow much lager than their relatives that live as where. There are other animals that follow this rule such polar sea sponges that can grow up to 2 meters in height.

This phenomenon occurs because the freezing cold waters of the polar region are more dense which allows it to absorb more oxygen. Since the oxygen rich water is dense, it sinks to the bottom of the ocean supplying all life there with an abundance of oxygen. Bergman’s law also comes into play. Due to the low temperatures in the environment, their metabolism slows down and their cells increase in size. Thus increasing their lifespan. With a long lifespan and a rich supply of oxygen, these invertebrates grow are able to grow massively.