According to a study published this Monday in the journal Philosophical Transactions of the Royal Society B, a group of researchers from the Duke University might have discovered the explanation of one of the rarest creatures present in the deep ocean: the “Cockeyed” squid.
It is known among the scientific community that the deep sea is the home of the rarest and oddest creatures of the planet. The “Cockeyed” squid might be one of the most accurate examples of these unique animals. This sea creature features a set of different eyes that even have different biological functions. Also, the size and color of both organs are considerably distinct.
Until the latest study, researchers in many investigation centers were not able to determine the real reason to explain this odd feature present in the “Cockeyed” squid. This sea creature, officially known as Histioteuthis heteropsis, has intrigued the whole investigation community since its discovery over 100 years ago, as the answer was somehow achieved by the researchers at the Duke University.
‘Cockeyed’ squid anomaly: A rare functional feature
The research team went over hundreds of pieces of records and data that could explain the mismatched eyes in the “Cockeyed” squid. They analyzed video registers from more than 150 footages of the squids swimming in the Monterey Submarine Canyon in Monterey Bay, Calif. Over the last 30 years, a variety of this species populations had undergone over investigations regarding, for example, its rare “up-side down” swimming method.
According to the results presented in the publication, the researchers determined that each eye had different characteristics as each one of them must comply a different task in the squid’s biological system. After analyzing every video and conducting light and simulation testing, the scientists concluded that the bigger eye located on the top of the animal is in charge of recognizing any shadows from fish nearby while the smaller one located downward is in charge of localizing any potential risks in the squid’s perimeter.
“Eyes are really expensive to make and maintain,” lead study researcher Kate Thomas, a graduate student of biology at Duke University, said in a statement. “You want eyes just big enough to do what you need to do, but you don’t want to have any bigger eyes, because then you are just wasting resources.”
According to the study, each eye cannot fulfill the other eye’s responsibility. This is because every eye possesses different features and organical compositions. For example, the smaller eye cannot detect the shadows from the fish that are beneath the squib itself. These organs are able to detect, instead, bioluminescence. This particular light is chemically produced, which comes from specific animals like deep sea fireflies and fish, and can be detected by the smaller eye thanks to its specialized visual structure.
The scientists defined that bigger eyes don’t translate into more chances of detecting several types of lights, unlike the smaller eye abilities. However, the investigations showed how the bigger eye is considerably more efficient on catching the sunlight that creates the fish’s shadows. So, even when this particular squid’s structure and appearance might look weird, the study was able to prove how these unusual characteristics are the ones that make life easier for this sea animal.
“The eye looking down really only can look for bioluminescence,” Sönke Johnsen, the study’s senior author and a professor of biology at Duke University, said in a statement. “There is no way it is able to pick out shapes against the ambient light. And once it is looking for bioluminescence, it doesn’t really need to be particularly big, so it can actually shrivel up a little bit over generations. But the eye looking up actually does benefit from getting a bit bigger.”
Living in the Twilight Zone? Time to adapt
According to the researchers, this unique visual feature might be the consequence of the environment in which this animal was forced to live due to its specific characteristics and system. The “Cockeyed” squid’s rare visual structure is the factor that actually makes possible for the animal to live in the extreme conditions of the Twilight Zone.
This area is located about 660 feet to 3,200 feet (200 to 1,000 meters) under the water’s surface. Since the sunlight that reaches this zone is barely enough to illuminate, the environment is dyed in a monochromatic dark blue color. A considerable number of species have adapted to this conditions by developing what is called “bioluminescence,” or the ability to glow in the dark.
According to Johnsen, this kind of creatures help all the current investigations enormously regarding eye functions and mechanisms. As the animals present in those areas must develop a different visual system, their adaptability allows the creation of a different eye structure, giving valuable information to scientists. And species that have developed the two different types of eye structures are the most interesting ones to study.
Source: Christian Science Monitor