Adult Bobtail Squid -Euprymna scolopes – otlibrary.com

Native to the Pacific Ocean, this species can be found in shallow coastal waters off Hawaii. It buries itself in sand or muddy areas near sea grass beds during the day—even gluing sand grains to its body to form camouflage—and emerges at night to feed.
This pear-shaped squid is akin to a wizard with its own invisibility cloak due to a symbiotic relationship with bio-luminescent bacteria that lives in a special light organ in its mantle. When the squid leaves the safety of the seafloor to hunt at night, the bacteria hides the squid’s silhouette by matching the amount of light hitting the top of its mantle—making it virtually invisible in moonlit waters when viewed from below. In return, the small squid provides the bacteria with a sugar and amino acid solution to feed on.
Hawaiian Bobtail Squid hatch-lings are not born with this bacteria; they secrete a mucus around their light organs to capture it. Less than a day after hatching, juvenile squid are able to “disappear” from predators just like their elders.
Materials science experts in the U.S. Air Force have studied the symbiotic relationship between the squid and its bacteria to see if the reflective qualities could be used to improve their aircraft camouflage.

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