These Sharks Can 'Glow In The Dark' Or 'Disappear' At Will
If you were impressed by Hermione's firm grasp of the 'lumos' spell or envious of Harry Potter's invisibility cloak than you are going to be rendered speechless by these Lantern Sharks who have figured out how to 'light' up or power down and 'disappear', whenever they wish to!
The most recent study focused on the Splendid Lantern Shark, a rare dogfish shark that resides in the deep waters of the East China Sea and off the coast of Taiwan and Japan. A team of researchers headed by Julian Claes at the Catholic University of Louvain's Marine Biology Lab captured three members of the species and observed their behavior in captivity.
What they discovered was fascinating -The fish were not only able glow-in-the-dark at will, but also, make themselves 'invisible' when faced with a predator. The ability to do this is controlled by light-emitting organs called photophores. In this particular specimen, the researchers discovered several distinct body areas from where the light was emitted, including the belly, flanks, tail and pectoral fins. The researchers believe that the sharks light up when they are trying to attract other sharks, communicate with each other or, when schooling.
To become invisible or camouflage itself against predators, the shark uses another neat trick, called counter-illumination. With the help of its photophores, it transmits the same intensity of light that is coming in from the sun above and blends in, so that all its predators who are looking upwards from its belly, (which is the only lit up section) see is a spurt of blinding light. And, it gets better. Since the shark has no way to regulate its brightness, it regulates its depth. During the day, when the sun is brightest, it swims deeper in the ocean, while at night, it floats nearer the surface, effectively remaining camouflaged as long as it wishes to.
So how does this Lantern Shark turn it's light switch off and on? Turn's out it's a seamless coordination of hormones - the chemical messengers that flow through our blood stream and relay messages to their target organs - and, nerves.
The researchers were able to identify two hormones that help with the light control - melatonin and prolactin. The first one helped induce a slow, longer-lasting glow, while the second is responsible for an hour-long quick spurt of light that scientists believe may be used for communication. The 'off' switch is controlled by a neurotransmitter called GABA. Ironically, the same hormones and neurons are present inside our bodies - Unfortunately, they do not help us glow in the dark or disappear!
The researchers believe that the lantern sharks developed these amazing survival techniques about 65-75 million years ago, when they first started to move into the deep sea.
Also, this is not the first species of the Lantern shark known to have these 'Harry Potter' like capabilities - A few years ago, Mr. Claes and his team did a similar study with the Velvet Belly Lantern sharks that reside off the coast of Norway, and ended up with similar observations. And, they are not done yet - With at least 33 other species of the same shark family known to exist, they are just at the beginning of some exciting new finds - So stay tuned!
Resources: wired.com,msnbc.msn.com, news.discovery.com, sharks.org
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