The strange cross-eyed squid’s disproportionate eyes allow them to adapt to two different bodies of water in the ocean.
Squid’s left eye is much larger than the right eye, helping them detect prey or enemies above. Photo: MBARI.
The “cross-eyed squid” is a mysterious creature of the ocean. They live suspended between two worlds: Above is the surface of the sea glimmering with sunlight shining through the blue water; Below is the deep water, completely hidden from the light.
Their developed “misaligned” eyes allowed them to see both worlds, at the same time.
This squid is born with two identical eyes, but the left eyeball usually grows faster, forming a long tube with bright yellow lenses. This giant left eye is very sharp in looking upwards, foraging or alerting to predators swimming overhead. The yellow color of the eyes filters light to detect the camouflage of glowing animals, trying to hide in the blue surrounding them.
Meanwhile, the right eyeball is less than half the size of the left eye. This eye is usually directed downward to scan the light of glowing creatures in the deep dark waters.
“It’s a fascinating demonstration of how they exist between two very different habitats,” said Jon Ablett, senior curator of mollusks at the Natural History Museum in London.
The red dots on the squid body are luminous organs, called luminescent cells. Photo: Kate Thomas/Duke University.
The crossed-eyed squid (Histioteuthis heteropsis) is no stranger to science, and was recently encountered by a research team during an expedition around the Atlantic islands of Ascension and Saint Helena. They are also known as gem ink when their whole body sparkles with ruby red spots when exposed to UV light.
James Maclaine, senior curator of fish at the Natural History Museum, said no scientists had tried to shine UV rays on deep-sea animals. Mr. Maclaine found that several other species had glowing red spots, such as both the gem squid and the viper; some species, such as the lantern fish, do not.
The red dots are glowing organs, called luminescent cells, that emit blue light when the squid is swimming hundreds of meters underwater. Since there is no deep-sea UV light, the luminescent cells do not glow red in the natural environment.
The “squishy squid” can use luminescent cells to glow to hide its own shadow. The flashing of cells could also be a form of communication between the squid and to attract mates or to lure prey.
