WHERE’S WALDO? That might be the question this yellow stingray (Urobatis jamaicensis) hopes we’re asking, as it fluffs up sand to try to hide itself. In this case it didn’t work since we watched it approach and then proceed to bury itself – most ineffectively. YELLOW STINGRAY FACTS U. jamaicensis typically measures 12 to 15 inches across, excluding the tail (although the Pittsburgh Zoo & Aquarium, which has yellow stingrays in its collection, says they
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SCIENTISTS STUDYING A SPECIES OF RAYS CALLED LITTLE SKATES have demonstrated that walking capabilities had developed in fishes dwelling on the seabottom millions of years before the first marine animals climbed out of the oceans to become air-breathing, leg-walking land dwellers. And they show how they moved with a video of modern little skates – little skate is the fish’s common name, not just a description – do it, utilizing a set of fins to
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SHARKS’ REPUTATION AS FIERCE, MAN-EATING APEX PREDATORS of the oceans takes a hit when you consider the bonnethead shark (Sphyrna tiburo), a small variety of hammerhead found mostly in warm waters along the Atlantic and Gulf coastlines of North and South America. Along with their normal carnivorous diet, bonnetheads eat grass, as in seagrass. How much grass? It accounts for as much as 62 percent of its gut content in some juvenile populations. The bonnetheads’
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THE EXTREME COLD GRIPPING MUCH OF THE NATION at present is likely a factor in the deaths of three thresher sharks, whose bodies have washed ashore on Cape Cod in recent days. As northern waters cooled, the sharks were probably migrating south along the coast, got trapped in Cape Cod Bay and ended up at the shore near bay-side towns Wellfleet and Orleans, according to a news article about the freezing weather nationwide in the
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A BILL BANNING THE SHARK FIN TRADE IN THE UNITED STATES appears likely to be passed by Congress, based on a hearing earlier this month by a House subcommittee. BIPARTISAN SUPPORT With 200 co-sponsors, HR1456, the “Shark Fin Trade Elimination Act,” has strong bipartisan support in the House and a similar bill under consideration in the Senate has 19 co-sponsors. The hearing by a subgroup of the House Committee on Oversight and Government Reform was described
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Atlantic torpedo rays aren’t your usual, charismatic touristy rays, like mantas, spotted eagles or even southern stingrays. In a way, they’re more interesting. It’s not for nothing that members of the family Torpedinidae are called electric rays. The Atlantic torpedo (Torpedo nobiliana) is one of 14 species of Torpedinidae rays worldwide that can deliver an electric shock – most producing less than 80 volts. T. nobiliana delivers up to 220-volts – probably not enough to kill
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A STUDY OF 17 SHARK SPECIES has determined that the animals have only one type of photoreceptor cells in their eyes, leading researchers to conclude that they are potentially completely color blind. The work by Dr. Nathan Scott Hart and colleagues at the University of Western Australia and the University of Queensland found that sharks have only a single long-wavelength-sensitive type of cone in their retinas. The findings were published in Springer’s online journal Naturwissenschaften
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KILLER SHARKS! MEGA SHARKS! SHARK DISASTERS! Shark Weeks on cable is great for people who don’t really care about or know about sharks. But…. AN ALTERNATIVE VIEW Here’s a link to a Vox.com article I like from 2015 on “Sharks as you won’t see them on Shark Week: Intelligent and remarkably social animals.” FACTS. AND MORE FACTS! And here are some facts from the University of Florida’s Florida Museum on the risks of being killed by
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ABOUT 40 PERCENT OF BONY FISHES live in freshwater but only five percent of sharks, rays and skates can do so. There a number of reasons cartilaginous fishes don’t do well in freshwater, including problems with dehydration and reproduction. SINK OR SWIM. MOSTLY SINK A team of American and Australian scientists have determined that another reason is an inability to maintain buoyancy control in freshwater. In short, in freshwater, sharks and their kin would tend to sink like newbie divers. NEEDED: LARGER
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UNLIKE BONY FISHES, SHARKS maintain buoyancy with oil-filled livers rather than bony fishes’ air bladders. Recently, it was revealed that doesn’t work well for them in freshwater, where they tend to have poor buoyancy (see “In Freshwater, Sharks Can’t Control Buoyancy“). DEEP-WATER SHARKS CAN Now a study has found that deepwater sharks, such as the bluntnose six gill shark, have better than average buoyancy at the depths they frequent. Science writer Chris Cesare describes the study in an AAAS ScienceShot
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