Question

What is the heaviest mollusc in terms of mass?

Answer 1

Hint: Mollusc is the second largest phylum which comprises of invertebrates. These organisms can live on land as well as water. The heaviest mollusc is found in the Antarctic Ocean and weighs up to 500Kg. The length of this mollusc is estimated to be around 9-10 meters.

Complete answer:
Molluscs are the unsegmented animals with soft bodies. The body is differentiated into muscular foot, head. They body organisation is organ system type of organisation. These organisms secrete calcareous shells. It includes snails, octopus, squids, oysters, chitons etc.

The heaviest of the mollusc is the colossal squid which lives in the southern oceans. The organism has all the features of squids like mantle for locomotion, a pair of gills, eight arms, two tentacles, head, and two fins. It is the only squid which has swivelling or three pointed hooks present on its arms and tentacles.

This organism exhibits abyssal gigantism. It is the heaviest invertebrate and can weigh around 495 kg. They feed on larger and smaller fishes and other squids. It is a slow-moving ambush predator which requires very less amount of energy and uses its eye for catching and detecting its prey. These organisms have distinct sexes and develop as they grow. The figure below shows the colossal squid.

Note: The colossal squid can detect bioluminescence which is produced by other animals. They are not caught by the humans for food. The interaction with the humans is very rare. The big whales prey over colossal squids. The giant squid is the largest mollusc but the colossal squid is heavier in mass.