“Lopsided Eye Squid” has one large, yellow-green eye, while the other eye is transparent and significantly smaller.
Histioteuthis heteropsis, commonly known as “Lopsided Eye Squid.” They are named for their remarkably different eyes in terms of size, color, and function.
Histioteuthis heteropsis, also known as “Lopsided Eye Squid.”
One of their eyes is yellow-green and large, while the other is transparent and much smaller.
The reason this squid species has such different eyes remains a question that has puzzled scientists for over 100 years.
Researchers at the Monterey Bay Aquarium Research Institute (MBARI) analyzed video footage of the “Lopsided Eye Squid” collected over the past 30 years and found that they have a tendency to swim at an angle, with the larger eye facing upward and the smaller eye facing downward.
Scientists believe that the large eye of the lopsided eye squid is sensitive to light, often facing upward where it can capture more sunlight to search for food and observe predators swimming above. The smaller eye, while less sensitive to light, can detect bioluminescent signals, helping them identify hidden predators lurking in the deep sea.
Jon Ablett, Senior Mollusks Manager at the Natural History Museum in London, stated: “It’s an intriguing example of how they exist between two very different habitats.”
This squid species is well-known in the scientific community, and it was recently encountered by a research team during an expedition around Ascension Island and Saint Helena in the Atlantic Ocean. They are also referred to as jewel squid due to their bodies shimmering with ruby-red spots when illuminated with UV light.
The red spots on the squid’s body are bioluminescent organs, known as photocytes. (Photo: Kate Thomas/Duke University).
James Maclaine, Senior Fish Curator at the Natural History Museum, noted that no scientist has ever attempted to shine UV light on deep-sea animals. He discovered that some other species also exhibit red bioluminescent spots, such as jewel squids and viperfish, while others, like lanternfish, do not.
The red spots are bioluminescent organs, known as photocytes, that emit blue light when the squid swims at depths of hundreds of meters underwater. Since there is no UV light in the deep sea, these photocytes do not emit red light in their natural environment.
“Lopsided Eye Squid” can use photocytes to illuminate and mask their own shadow. The flickering of these cells may also serve as a form of communication among squids and attract mates or lure prey.
