英语论文网

The researchers recently observed a wild bottlenose dolphin following a precise series of maneuvers to kill, gut, debone and de-ink a cuttlefish for a perfect mollusk meal. (China Daily)
They can't wield a knife or cleaver, nor are they experts with ladles and spatulas, and pots and woks. But they are chefs, all the same, complete with all the subtlety and finesse.
We are talking about dolphins, well at least one, which Australian scientists have seen going through elaborate preparations to rid cuttlefish of ink and bone to enjoy a soft meal of calamari.
The researchers recently observed a wild bottlenose dolphin following a precise series of maneuvers to kill, gut, debone and de-ink a cuttlefish for a perfect mollusk meal.
Julian Finn, a marine biologist at Museum Victoria in Melbourne, observed a single female dolphin performing the move in 2003 and again in 2007. At the time, he was studying mating in cuttlefish, which breed in large swarms in South Australia's Upper Spencer Gulf.
The female Indo-Pacific bottlenose was seen repeatedly catching, killing, and preparing giant cuttlefish, which are relatives of octopuses and squids, and spawn in huge numbers.
"It's a sign of how well their brains are developed. It's a pretty clever way to get pure calamari without all the horrible bits," says Mark Norman, curator of molluscs at Museum Victoria and a research team member.
Despite their lack of limbs, dolphins have developed clever ways to use their snouts, says study co-author Tom Tregenza, at the University of Exeter. "A dolphin is like a genius trapped in the body of a fish."
The six-step procedure begins with the female dolphin shooing a cuttlefish out of an algal forest into an open patch of the seabed. Next, she pins the invertebrate down, ramming it into the ground. To rid the body of ink, she uses her snout to pick up the cuttlefish and shake it several times till a black cloud streams out.
The dolphin then grinds the cuttlefish along the sea floor to break its bone with a "loud click", audible to divers as the hard cuttlebone breaks. "The cuttlefish bone pops out like a bar of soap," and dinner is served, says Tregenza.
Norman and Tregenza say the behavior exhibited between 2003 and 2007 was unlikely to be a rarity. "In addition to our observations, individual bottlenoses feeding at these cuttlefish spawning grounds have been observed by divers in the area to perform the same behavioral sequence," they have said in the study.
A separate 2005 study provided the first sign that dolphins might be capable of group learning and using tools, with a mother seen teaching her daughters to break off sea sponges and wear them as protection while scouring the seafloor in Western Australia.
The mammals used the sponges "as a kind of glove" while searching for food, University of Zurich researcher Michael Krutzen told New Scientist magazine.
Other researchers have observed dolphins removing the spines from flathead fish prey and breaking meter-long Golden Trevally fish into smaller pieces for eating.
Source: China Daily/Agencies