The Strawberry Squid: A Deep Ocean Dweller with a Unique Hunting Strategy

Continue reading for our analysis...

Deep below the surface waters of the ocean lives a mysterious world filled with alien-like creatures. Floating around this dark and eerie place are fascinating animals with the ability to create their own light in the murky depths. It’s called the twilight zone, and it’s so deep that sunlight barely penetrates. In these dim waters lives the strawberry squid, an amazing little bright red creature with two completely different-sized eyes.

The Monterey Bay Aquarium Research Institute (MBARI) captured stunning footage of the strawberry squid during a deep sea dive. Check out the video above for a close-up of this sea creature that is seldom seen. The footage is so clear that you can easily spot the little squid’s two eyes — one large and one small. Read on to learn how the strawberry squid benefits from its unusual set of eyes.

What Is the Strawberry Squid?

There are around 300 species of squid living in the ocean and they can range in size from less than an inch to the massive 50-foot-long giant squid. The strawberry squid (Histioteuthis heteropsis) is much smaller than the giant squid. It reaches around eight inches in length (about the length of a large banana.) Other common names include the jewel squid or the cockeyed squid. Like many creatures living in the deep ocean, the strawberry squid can light itself up using bioluminescence. The squid floats along the water upside down with one eye aimed at the ocean floor and the other looking above.

Named for its bright red color, the squid has red-tinted photophores (light-emitting organs) across its skin. Although bright red doesn’t sound like much of a camouflage, the color appears dark in the deep waters and helps the squid hide from predators.

Where Does the Strawberry Squid Live?

During the day the strawberry squid swims around in the twilight zone of the Atlantic Ocean in a range of about 660 to 3,300 feet below the surface. It can be found in tropical and subtropical waters. Here in the twilight zone, where the sun barely reaches, even plants cannot grow. The pressure is high the lower you go, but the animals that make it their home have adapted to the extreme pressure. However, the depth and pressure make it hard for scientists to study the animals that live here. We are still learning about this mysterious place.

The squid lives in the twilight zone during the day, hiding from predators in the darkness. At night, like many other animals that live in the twilight zone, it migrates to more shallow waters in search of food. Each night it reaches the upper layer of the ocean, or sunlight zone where food is more plentiful.

How the Strawberry Squid’s Eyes Help It Hunt

When you watch the video from MBARI you can see the strawberry squid gently floating through the water with its two differently sized eyes. These two strange eyes are the perfect combination that makes the strawberry squid a formidable hunter in the deep sea.

The cephalopod’s right eye is small and dark, while the left eye is larger and dome-shaped. The large left eye looks upward, searching for a silhouette against the faint light above. That silhouette is a tell-tale sign to the squid that prey is nearby, or on the other hand, to watch out for a predator looming above.

The smaller right eye faces downwards, and its job is to catch the faintest glow of bioluminescent light from below. This lets the squid know if prey is swimming underneath, or if it’s time to get out of the way from a predator.

These two eyes allow the strawberry squid to do a remarkable thing. It can see right through another animal’s counter-illumination camouflage. The squid does this thanks to the yellowish tint of its large left eye. This color helps the squid filter out blue light, which means it can spot silhouettes from creatures above.

Athletes Use Yellow-Tinted Lenses to Improve Eyesight

Athletes have discovered what the squid evolved to do millions of years ago. Yellow-tinted lenses help athletes see better by filtering out certain wavelengths of light. Just like the squid’s yellow eye searching for a silhouette above, yellow-tinted glasses help athletes to see with better clarity and contrast.

Why Is the Strawberry Squid’s Right Eye So Much Smaller?

The strawberry squid’s left eye needs to be large to catch movement from above. But the smaller right eye is only searching for flashes of light from other creatures’ bioluminescent glowing. Over time as the squid evolved, scientists believe this eye reduced in size and became smaller than the left eye because it didn’t need to be as large for its job.