This very nice article in the NY Times (requires free registration, though!) on research by Dr. Roger Hanlon to understand and push the abilities of cephalopods — cuttlefish, octopus and squid — to camouflage themselves against predators. From the article:
Dr. Hanlon has watched octopuses perform what he calls the Moving Rock Trick. They assume the shape of a rock and move in plain sight across the sea floor. But they move no faster than the ripples of light around them, so they never seem to move.
And this:
Evidently, they have to hide even in darkness from dolphins and other predators.
Also:
Cuttlefish can also use camouflage to deceive other cuttlefish, Dr. Hanlon and his colleagues have found. A male cuttlefish will typically guard several females from other challengers. He does not often have physical fights. It is enough for him to put on a powerful visual display.
But if another male disguises its skin to look female, he can sneak up to the guarded female and mate. The sneaky male’s disguise may be so good that the other male may try to guard him as part of his harem.
Finally, here’s what is funny about the whole thing:
Experiments in Dr. Hanlon’s lab have shown that they are color blind. They see a world without color, but their skin changes rapidly to any hue in the rainbow. How is that possible?
Highly recommended!!
Another article in the NY Times, this time a book review of “Your Inner Fish” by Neil Shubin. One of the things the book apparently talks about is how many of the human physical traits have first evolved in fish, which by itself is not all that surprising. What is really fascinating, though, is this:
Our inner fish extends beyond physicality. New research reveals that many fish display a wide range of surprisingly sophisticated social behaviors, pursuing interpersonal, interfishal relationships that seem almost embarrassingly familiar.
“Fish have some of the most complex social systems known,” Michael Taborsky, a behavioral ecologist at the University of Bern in Switzerland, said. “You see fish helping each other. You see cooperation and forms of reciprocity.”
Dr. Taborsky and his colleagues have studied the social lives of African cichlids, colorful freshwater fish from Lake Tanganyika. The cichlids live in relatively large groups of 10 or so individuals, a dominant breeding pair and a retinue of adult and adolescent helpers. The helpers share in all duties, Dr. Taborsky said. They defend territory, they help keep the nests tidy and they clean, fan and oxygenate the breeding pair’s eggs. When the eggs hatch into larvae, the helpers take up the babies in their mouths for cleaning — all the while forgoing their own breeding efforts.
Significantly, the helper fish are often unrelated to the royal pair over whose spawn they so officiously fawn. What’s in it for the helpers? “We call it pay to stay,” Dr. Taborsky said. “Helpers are allowed to stay in the territory and gain security and protection against predators. But they have to pay rent, so to speak, or they risk being expelled.”
In laboratory experiments, the researchers have shown that when subordinate cichlids are temporarily prevented from performing their duties, the fish compensate at the first chance by ostentatiously redoubling displays of helpful behaviors.
Haven’t we all had the urge to display such ostentatious behavior, more so as children and less so later on, to make ourselves more acceptable to others? I hope to get my hands on this book sometime!!
Posted by srinivasv 
Posted by srinivasv 
Posted by srinivasv 