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Wednesday, 11 March 2009

Animals special - dolphins, ants and bipolar species

Today:

  1. Dolphins are capable sea chefs, scientists say
  2. Ants tricked into raising butterflies
  3. Researchers say animals plan for the future
  4. Ocean survey reveals hundreds of 'bipolar' species

Dolphins are capable sea chefs, scientists say

CANBERRA (Reuters) – Dolphins are the chefs of the seas, having been seen going through precise and elaborate preparations to rid cuttlefish of ink and bone to produce a soft meal of calamari, Australian scientists say.

A wild female Indo-Pacific bottlenose dolphin was observed going through the same series of complicated steps to prepare cuttlefish prey for eating in the Spencer Gulf, in South Australia state.

"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," Mark Norman, the curator of mollusks at Museum Victoria and a research team member, told the Canberra Times newspaper.

The research team, writing in the science journal PLoS One, said they repeatedly observed a female dolphin herding cuttlefish out of algal weed and onto a clear, sandy patch of seafloor.

The dolphin, identified using circular body scars, then pinned the cuttlefish with its snout while standing on its head, before killing it instantly with a rapid downward thrust and "loud click" audible to divers as the hard cuttlebone broke.

The dolphin then lifted the body up and beat it with her nose to drain the toxic black ink that cuttlefish squirt into the water to defend themselves when attacked.

Next the prey was taken back to the seafloor, where the dolphin scraped it along the sand to strip out the cuttlebone, making the cuttlefish soft for eating.

Norman and study co-author Tom Tregenza, from the University of Exeter, said the behavior exhibited between 2003 and 2007 was unlikely to be a rarity.

"The feeding behavior reported here is specifically adapted to a single prey type and represents impressive behavioral flexibility for a non-primate animal."

A separate 2005 study provided the first sign dolphins may 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

My comment: Awesome, right :) I'm not in the bit surprised, I've seen my dog accommodating his food (or bowl) for best or easiest feeding. I've seen even goats having all those tricks for special types of food. And the dolphins are so much more intelligent. Even if it sounded kind of cruel the way they are snapping the bones of the thing. But then, they have to eat too. It's funny to think about dolphins as predators. They are so cute and they break bones. Nice...

Ants tricked into raising butterflies

February 5th, 2009

(AP) -- Flitting across your yard, butterflies seem friendly and harmless. But at least one type has learned to raise its young as parasites, tricking ants into feeding it and giving special treatment.

The pupae of the European butterfly Maculina rebeli exude a scent that mimics the ants and make themselves at home inside the ant nest. Once they become a caterpillar they even beg for food like ant larvae, researchers report in Friday's edition of the journal Science.

It turns out that ant queens make subtle sounds that signal their special status to worker ants. The caterpillars have learned to mimic those sounds, the researchers say, earning high enough status to be rescued before others if the nest is disturbed.

In times of food shortage, nurse ants have been known to kill their own larvae and feed them to the caterpillars pretending to be queen ants, they added.

In nature, the real ant queen and the caterpillar keep to different parts of the ant colony and would not encounter one another, the report said.

But in an experiment, a butterfly pupa pretending to be an ant queen was placed in a chamber with worker ants and four real ant queens. The ant queens began to attack and bite the caterpillar, but the workers intervened, biting and stinging their own queens, which they then pulled to a far corner of the chamber while other workers attended the pupa. source

My comment:Haha, isn't that nice :) What's amazing is not that the ants are that stupid, because they are not. The thing is that the pupa learnt so well their "language" it's able to pretend to be one of them. Fun.

Researchers say animals plan for the future


CHICAGO – Monkeys perform mental math, pigeons can select the picture that doesn't belong. Humans may not be the only animals that plan for the future, say researchers reporting on the latest studies of animal mental ability.

Wasserman, a professor of experimental psychology, said that, like people, pigeons and baboons were able to tell which pictures showed similar items, like triangles or dots, and which showed different items. This is the definition of a concept, he said, "and the animals passed it with flying colors."

In the last 20 years there has been a major revolution in the understanding of animals, added Nicola S. Clayton, a professor of comparative cognition at the University of Cambridge in England.

Animals not only use tools, there is evidence that some of them save tools for future use, she said. "Planning ahead was once thought to be unique to humans," Clayton said. "We now know that's not true."

For example, she said, crows have been seen stashing food away for the next day and even finding ways to protect it from being stolen.

Speaking of crow intelligence, Alex Kacelnik, a professor of behavioral ecology at the University of Oxford in England, noted the "master tool user of the avian world," the New Caledonian crow. These birds have been shown to not just use tools, but to make their own by twisting and bending pieces of wire to fish food from places they couldn't reach otherwise.

Jessica Cantlon of Duke University noted that "number sense" seems among the shared evolution of many primates. Cantlon and Elizabeth Brannon have studied how human adults and babies, lemurs and monkeys think about numbers without using language.

After seeing the same number of objects repeatedly in different-looking groups, infants notice when the number of objects is changed, they found. So, too, do macaques.

Indeed, college students and macaques seem equally able to roughly sum up sets of objects without actually counting them.

That abiliity can be useful to the macaques in determining whether there is enough food to remain in an area or to get a sense of how large their group is compared to competing groups.

They are currently working to see if monkeys can recognize the concept of zero. source

My comment: I remember I wrote about this before, but I can't get enough on the subject. What strikes me is that owls use wire-something that isn't found in Nature and that wouldn't probably be usable if instead of wire, the owl tries wood to produce a tool. Of course, that could be just a wild guess, maybe they would find a way to use wood as well, but for me, that might means that animals are evolving with us too. Like everyone is getting smarter. And maybe that makes sense-for example a wolf, wouldn't know how to dial 911 or smell heart attack-something that dogs can be trained to do. By requiring from the animals more, or putting them in different environment, we're actually provoking their skill to manifest. Isn't this cool?!

Ocean survey reveals hundreds of 'bipolar' species

Poles apart, but intimately linked. Of the thousands of species that populate Antarctica and the Arctic, it seems hundreds are "bipolar": found spanning 11,000 kilometres between the polar regions.

See a slideshow of "bipolar" species (check it out, it's very beautiful)

The surveys, part of the international Census of Marine Life, also suggest the Antarctic acts as a cold incubator for species that populate the deep sea around the planet. As ice ages come and go, and the ice shelf advances and retreats, species are isolated, evolve, then released to the global sea floor.

The 235 species that we believe are found at both poles include a great variety of animals, says Julian Gutt of the Alfred Wegner Institute for Polar and Marine Research in Germany. The easiest ones to explain are the large migrating organisms, such as whales and birds. But the list also includes a large number of animals that are thought to live relatively sedentary lives.

How species that live attached to the seafloor came to span 11,000 kilometres of ocean is a bit of a mystery, say the researchers. Gutt's best guess is that their floating larval stage is the key.

DNA bar-coding experiments are underway at a facility in Canada to confirm the identity of the sampled species, but it is unlikely that all 235 pairs of species are identical or different.

Expeditions carried out under the auspices of the Census of Marine Life also revealed that the Antarctic acts as a cold incubator for the rest of the world's seafloor communities.

The Antarctic team at the Census of Marine Life now believe some of these species end up venturing into the deep ocean.

More than 30 million years ago there was not enough oxygen in the deep ocean to support life. But creatures that live there now had to come from somewhere. As some of the conditions in the deep ocean are similar to those on the continental shelf of Antarctica, it is possible that is where the ancestors of deep ocean species came from.

Genetic studies on several species of Antarctic octopus and crustacean have previously confirmed this. source

My comment: Check out the pictures, they are very pretty. I can't really comment more, but I find the variety in this ice-waters for very interesting.


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