Squids are fascinating creatures that inhabit the world’s oceans and can measure more than 4m in length.
In this video they captured a unique ability of these aquatic animals: color change. The video shows a person lifting a dark black squid out of a water tank, and as he pulls it out, the creature becomes almost completely transparent. When the squid returns to the tank, it returns to its original deep black color.
Masters of camouflage
Cephalopods including octopuses, squid and cuttlefish have the ability to rapidly change color and pattern in their skin, which allows them to camouflage themselves and communicate with other animals. To achieve this, they have complex multicellular organs that allow them to rapidly change color and produce a wide variety of bright patterns and hues.
Each chromatophore unit in the skin of these animals is composed of a single chromatophore cell and multiple muscle, nerve, glial and sheath cells. Inside the chromatophore cell, the pigment granules are enclosed in an elastic sac called a cytoelastic saccule, which expands or contracts depending on the nerve signal it receives. In this way, cephalopods can change color in a matter of seconds to camouflage themselves or communicate with other animals.
This ability is achieved by the layers of stacked cells in their skin, such as chromatophores, iridophores and leucophores. The combination of these cells operating together allows cephalopods to produce a wide variety of colors and patterns. In addition, some octopuses can also change the texture of their skin to mimic the appearance of rocks and other marine objects to protect themselves from predators.
To change color, a cephalopod distorts the sacculus through muscle contraction, changing its translucency, reflectivity or opacity.
How can it become almost transparent?
Some cephalopods have the ability to become completely transparent, allowing them to hide from predators and stalk their prey unseen.
Transparency in cephalopods is achieved by a combination of factors. First, their skin contains special cells called leukophores, which contain microscopic crystals that reflect light instead of absorbing it. This allows light to pass through the skin of the cephalopods, making them transparent.
In addition, some cephalopods, such as the glass squid and the glass cuttlefish, have a particularly transparent skin due to the lack of pigmentation in their cells. In these animals, light simply passes through the skin without being scattered by pigments.
“As for what triggered the behavior, the animal was stressed by being taken out of the water, most likely it was a fear response. They communicate with colors and patterns and can alter their colors and patterns in selected areas.”Charles Delbeek (Curator of the Steinhart Aquarium)
In general, transparency in cephalopods is an important evolutionary adaptation that allows them to survive in their marine environment. Thanks to this ability, cephalopods can move stealthily and avoid predators, giving them an important advantage in the struggle for survival in the ocean.
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