While a squid can often be confused with an octopus, these soft-bodied mollusks are very different for many reasons. Aside from their size and body, these animals can camouflage too! They also have remarkably interesting defense mechanisms and are great hunters. Although squid have large predators and are also used for human consumption, they are a unique addition to the ecosystems of our oceans.
Let’s learn more about these amazing creatures by exploring 10 incredible squid facts!
1. Cuttlefish are cephalopods
Although squids are mollusks, they also belong to the cephalopods class. A cephalopod is composed of cuttlefish, octopuses, cuttlefish and nautilus. Cephalopods have bilateral symmetry with a distinct head and often tentacles. Like all cephalopods, they have a large, long head that is often confused with their bodies. They have an impressively functioning nervous system and a small internal skeleton in their soft body. Their skeleton is in the shape of a pen and consists mainly of a derivative of glucose.
2. Cuttlefish originated in the Jurassic era
In the Jurassic era, the squid diverged from other cephalopods, meaning the squid technically evolved over 100 million years ago! One of the prehistoric squids from which our modern squids originate is the fascinating Belemnotheutis Antiques. Scientists tracked this historic squid using a fossilized ink sac they found in England. The Belemnotheutis Antiques has some of the best preserved fossils. Scientists often refer to these fossils when trying to learn more about squids during the Jurassic period. They would have died out by being poisoned by algal blooms. These flowers often served as breeding grounds for thousands of these prehistoric beauties.
3. Cuttlefish can change color for camouflage purposes
One of the most fascinating facts about squids is that they can camouflage themselves by changing the colors of their skin! They often do this as a defense mechanism, to warn of or hide from potential threats and predators. They can do this because they have leukophores, reflectors that produce whiteness in their bodies. These pigmented, light-reflecting cells allow the squid to regulate the brightness, tone and color of their skin. The color spectrum is quite wide. In fact, many squids can change from their usual color to a variety of other colors. However, it mostly depends on the environment they are trying to camouflage in.
4. Cuttlefish use their ink as a defense mechanism
Like many cephalopods, squids have ink they project, often referred to as “squid” by fishermen. Their ink is composed of many compounds, enzymes, hormones and other properties. Their inks even contain composites of metals such as copper, lead and cadmium, as well as aspartic acid. Humans have been known to use cephalopod ink for coloring food and other forms of medicine. This is due to its high melanin properties. Interestingly, when a squid ejects its ink in defense, it does not technically harm the predator or threat. Instead, it creates a thick and dark cloud that often blocks their predator’s view. This gives them a window of escape.
5. There are more than 300 kinds of squid
Although at least 800 species of cephalopods are known, there are more than 300 known species of squid alone! These types are usually divided into two categories; myopsida and oegopsida. Myopsida squid consists of four orders of squid and is usually distinguished from oegopsida because of its eye structure. Oegopsida squid consists of 24 different families. They are usually categorized in this order because their heads have no tentacle sacs and their eyes have no corneal covering. Sometimes the arms and tentacles of these squids can even have hooks!
6. The largest squid is the colossal squid
Many claim that the giant squid is the largest squid on Earth. However, the colossal squid is actually a bit bigger. The colossal squid is the largest squid on Earth by mass. The size usually averages 1,000 pounds, and the cloak size is usually about 12 inches long. These are deep-dwelling squids. Their young usually swim at about 1,600 ft, while adolescents can be found anywhere between 1,600 ft – 6,000 ft. Adults usually live in zones between 3,000 ft to 13,000 ft below the ocean surface, where only 1% of light can reflect.
7. The smallest squid is the Thai bobtail squid
While many forms of larger squid are the most discussed, the smaller species of squid are just as fascinating. The Thai bobtail squid is the smallest squid known on Earth. It averages about 0.4 inches in mantle length when they reach maturity. This squid is quite cute because its head is relatively large for its overall length. It has small, plump tentacles and large eyes that are located on the underside of the mantle.
8. A squid is great at hunting and attacking prey
Cuttlefish are carnivores and mainly feed on fish and crustaceans. Because they have such large arms and suction cups, they are good at catching larger animals in the ocean. Not only that, some of their saliva contains toxins, often suppressing their prey once it’s caught. They usually hunt by sight and touch, breaking out their long arms at a rapid pace. This helps them catch their meal before carving and swallowing their food with their little mouths. Some squid species use their poisonous saliva. Others use their hooks and suction cups. Some even use large flashes of light to confuse or disorient their prey before consuming them.
9. Squids Have Advanced Nervous Systems
Although squid have a relatively small skeleton, their amazing nervous systems make up for it. They have overly complex brains in the form of nerve rings around their esophagus. They also have a group of neuron cell bodies called the Ganglia. It is located above the esophagus and often receives sensory information from the eyes and other sensory receptors.
10. Cuttlefish can move in different ways
Not only are squids quite buoyant, but they also move incredibly fast and in different ways! They use slow movements, which propel the squid forward, a common mode of locomotion for them. Their most popular form of escape for exercise is by blasting. This is a contraction in their muscular wall in their mantle cavity, which allows them to propel forward as if propelled by a jet. They do this by absorbing a huge amount of water before quickly projecting it out. This allows the jet propulsion to take place and also allows them to escape or move at an otherwise faster rate.