Best Aquatic Animals with Amazing Visual Adaptations

Mantis shrimp – best color vision in the animal kingdom

Mantis shrimp have narrow, fast appendages. They have huge eyeballs on stalks. The mantis shrimp eye is distinctive. Mantis shrimp eyes constantly rotate. The mantis shrimp's eye has an upper, lower, and centre hemisphere. Mantis shrimp mid-band has 12-16 photoreceptors. Mantis shrimps have several colour channels and can sense polarised and UV light due to their intricate anatomy. This crustacean's eyes act like a satellite or video camera. Mantis shrimp's reniform body allows it to assimilate visual information.

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The common octopus – polarized vision without a blind spot

Octopi are camouflaged predators. They have good underwater vision with these features: Octopus eyes are 20 mm in diameter. Octopus eyes have spherical lenses. Invertebrates have more complex photoreceptors than octopuses. Octopus pupils can become huge or small. The octopus' eyes move independently and have different sight fields. No blind spot exists in the octopus' retina. Octopus photoreceptors detect polarised light. Researchers say octopus eyes are as keen as cats'. Octopi are colorblind, yet they can perceive polarised light and distinguish colour changes by changing their pupil and iris.

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Giant Squid – most prominent eyes in the world

Not only is this monster huge — some reach 39 feet – but its eyes are huge, too. Huge squid eyes can be as big as a human head. Human-like eyes with a large pupil. The squid eye anatomy isn't good for spotting prey or mates. Squid eyes can see in low light. Eyes of giant squid can perceive forms. According to a recent theory, the squid's huge eyes evolved to spot sperm whales, its principal predator. The squids' big eyes can detect a sperm whale shadow at 120 m.

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Four-eyed fish – sees both above and underwater.

It's river dwellers. Anableps have odd eyes. The eyes of Anableps are protruding. Each pupil is split, thus the fish seems to have four eyes. The eye of a fish is divided by an unfinished bone "plank" in its orbit. Duplicated pupils and corneas in Anableps eyes. Photoreceptors are distinct in the upper and lower eye. The upper component of the eye sees above water, while the lower part sees underwater.

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Banded Archerfish – the most acute vision in the freshwater fish

The archerfish hunts by "spitting" water at its victim. Archerfish have complex vision to do this. Archerfish eyes can identify small prey in the air against a leafy background. Archerfish find prey underwater. Archerfish eyes have multiple types of photoreceptors with varied sensitivities, allowing them to see airborne and underwater objects. Archerfish have excellent vision. Area centralis helps the archerfish analyse high-resolution pictures. Archerfish have 3.5 cycles per degree acuity. Other fish have acuity of 1-2 cycles per degree.

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Box Jellyfish – multiple different eyes

Jellyfish have nerve clusters, not a brain. Their visual system is unusual. Six eye clusters cover jellyfish. Eyes are pigmented holes. Each eye's lens has varied edges and centres, focussing light at a given point. Eyes can be specialised. 4 eyes can detect pictures above the water's surface.

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