(ORDO NEWS) — Zoologists have found that the cuttlefish’s disguise under the surrounding landscape is more difficult than previously thought.
The mollusk uses its cognitive abilities to read the patterns around it and reproduces them in the form of a whole range of dissimilar patterns and their combinations on its body.
Along with squids and octopuses, cuttlefish (say, medicinal cuttlefish – Sepia officinalis ) are highly organized cephalopods.
They live in the seas at different depths, where they lead a predatory lifestyle and sometimes surprise with the complexity of their behavior.
The trademark of cuttlefish , usually swimming near the bottom, is the famous camouflage. Once in a certain background, these animals change the color and patterns on the surface of the body thanks to special chromatophore cells that are controlled by their brains.
Previously, scientists believed that the regulation of the adaptive camouflage of cuttlefish is quite simple: there are supposedly only three main patterns, among which the mollusk “chooses” the most suitable one.
However, according to a new article published by scientists from the City University of London (UK) in the journal Current Biology , everything is much more complicated.
The cuttlefish uses about 30 different simple patterns in its camouflage pattern. Thanks to this, the animal realistically reproduces the seabed around it.
To understand how the cuttlefish manages to do this, the scientists tested whether it uses cognitive capabilities in doing so.
Fifteen cuttlefish were planted in containers with an unusual background. Some got “rooms” with gray walls, others with a simple pattern, such as small white or black squares, white stripes, checkered, and so on – seven different types in total.
In response, the cuttlefish acquired a strange camouflage that does not reproduce geometric shapes unusual for a sea mollusk.
Moreover, it turned out to be not what scientists expected to see. The animals were photographed, the images were analyzed, and they noted which of the 30 patterns available to the cuttlefish are visible in the photo.
To do this, zoologists used data analysis, namely the principal component analysis (PCA). It allows you to separate the set of points describing the data, having received their projection onto a two-dimensional space with specially selected new coordinate axes (principal components).
However, it was not possible to distinguish clear groups of patterns in this case, which contradicts the hypothesis of simple “elements” at the basis of the mollusk’s camouflage.
Apparently, cuttlefish still use a range of patterns, activating and adjusting them as needed. To do this, the mollusk cannot do without some “mental effort” and cognitive abilities.
Such a camouflage model provides for a hierarchy of reactions – there are a lot of them, but among them it is easy to distinguish large and small groups.
“Cuttlefish have been a great opportunity to explore visual perception with an outlandish species that displays what it sees as patterns on its body,” said Christopher Tyler, professor at City University London.
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