Asian Diver and Scuba Diver Issue 03/2017 (109) | Page 7

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DOLPHIN DESIGNS Male humpback dolphins in Northern Australia ’ s much-studied Shark Bay have been documented posing with sponges on their heads , while making a “ banana ” shape with their bodies , in bids to attract females .
Researchers from the University of Western Australia speculate that the sponges are probably quite difficult to remove from the sea floor , and the “ offering ” of one is likely to be a show of strength and ability . However , it doesn ’ t seem to be having the desired effect on the ladies , with one frustrated male even spotted throwing the sponge at his intended “ sweetheart ”.
The same researchers documented what appears to be rudimentary tool use amongst the dolphins of Shark Bay , with some of these charismatic cetaceans seen using sponges to protect their snouts when hunting .
TRULY ANCIENT MARINERS New research published in Science shows that Greenland sharks are the longest-lived vertebrates in the world , with radiocarbon dating revealing the oldest found to be 392 years old , plus or minus 150 years .
Greenland sharks live in the north Atlantic and grow up to six metres long , though only at a rate of a few centimetres a year . This slow growth rate leading to an adult of a large size is commonly an indicator of long-lived animals . Curious marine biologist John Steffensen at the University of Copenhagen , along with his graduate student Julius Nielsen , used radiocarbon dating and shark lengths to arrive at this astonishing figure .
Very little is known about this elusive species , though this new research suggests it is likely that females do not give birth to young until they are around 150 years old !
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