Colossal Squid Anatomy

Known as one of the largest creatures on the planet, the colossal squid is both terrifying and very interesting. Although it shares some of its taxonomy with its more diminutive relatives, there are still a handful of very distinct features to examine. So, let us have a brief look at the anatomy of this truly wonderful animal and a handful of the unique variations that set it apart from the rest.

The Mantle

This is actually a common term for the main body of any squid. It is often described as a protective "sheath" that fits over the internal organs. However, the sheer size of the mantle of this squid is daunting. It is said to be up to 2.5 metres long in many cases. To put this in perspective, the mantle can be equated to the width of a large truck tyre!

The Shell

The "shell" is actually a more common term for what is known as the gladius. However, this is not a shell in the traditional sense. The gladius is located underneath the mantle. It is defined as a plastic-like structure that protects the internal organs from damage. It begins through the front of the body of the squid and continues down until just before the tentacles emerge. The gladius is also known as being quite tough; illustrated by the fact that even the sperm whale (the only known predator of the colossal squid) may not always be able to pierce its torso.

The Tail Fin

This part of the squid's anatomy allows it to propel itself through the water using a flapping motion. It is adhered to the mantle and comprised mainly of muscle. Many onlookers will note that the tail fin is the most recognisable part of any squid. On the colossal squid, this fin can grow to well over one metre and due to its extreme muscularity, the fin is thought to be used as a forward propulsion device. This can help the creature to quickly escape predators or catch prey when necessary.

The Siphon

This is a structure located on the underneath (or ventral) portion of the mantle. The siphon is intended to remove waste products as well as to aid in respiration. Water is sucked into the cavity of the siphon and much like a gill, oxygen is separated from the sea water. However, it should be noted that the contraction of this siphon is partially responsible for the movement of the squid within the water (due to the water and waste shooting out at high speeds).


The two main tentacles of the colossal squid are approximately 2.1 metres long. An interesting feature relating to this species is that these tentacles have clubbed ends and rotating "hooks" that enable it to firmly latch onto its prey. There are also eight "arms" which are shorter than the tentacles. These help to manipulate food.

The Beak

The beak is a final part of the anatomy to observe. It is made of a hard substance known as chitin and is the first stage in digesting food. The beak will tear flesh apart due to its powerful muscles. Its size will directly relate to the overall size of the colossal squid in question.