Stories tagged dolphin

Jun
10
2008

Melon-headed whale
Melon-headed whaleCourtesy Minerals Management Service

Fifty-five melon-headed whales, a species tropical dolphin, have beached themselves in Madagascar and died. This is the first time these creatures are known to have visited the island.

Whales and dolphin periodically strand themselves on beaches, individually or in groups. No one knows why. They sometimes get "lost," swimming far inland up rivers. We have discussed such incidents on Science Buzz before: here and here and also here.

Nov
09
2007

Bring 'em on: Come on you nasty sharks...I'll take you all on. (Flickr photo by Cayusa)
Bring 'em on: Come on you nasty sharks...I'll take you all on. (Flickr photo by Cayusa)
The Miami Dolphins on the NFL football field maybe struggling through a winless season so far, but their namesakes off the coast of California chalked up a big win a few months ago.

When surfer Todd Endris was surfing near Monterey on Aug. 28, a 12- to 15-foot great white shark attacked him. It’s not uncommon for surfers to be the targets of sharks, who look up through the water to see what they think is a tasty seal.

Three shark bites peeled skin off his back and had ripped his right leg down to the bone. Then to the rescue came a pod of dolphins.

The formed a protective ring around him, allowing Endris to get his wits about him, paddle to shore and get first aid attention on shore from a friend.

I heard Endris share his tale on the Today Show earlier this week. You can get the full report by clicking here. But my biggest question was left unanswered. Why did the dolphins intervene?

Science doesn’t have the answer yet, but cases of dolphins rescuing people go back to tales from ancient Greece.

Just last year, four lifeguards in New Zealand were saved from sharks by the similar action of a pod of dolphins.

One more interesting twist to the story, within six weeks Endris was back on his surfboard riding the waters off on Monterey again.

So what do you think is at play with dolphins coming to the rescue? Do you think they do this for other species as well, or just humans? Share your thoughts here with Science Buzz readers.

I'm not dead yet!

by Gene on Aug. 31st, 2007

Contrary to previous reports, the Chinese river dolphin may not yet be extinct. A man claims to have videotaped an animal which may be a member of this critically endangered species.

Aug
08
2007

Enjoy the picture
Enjoy the pictureCourtesy Alessio Marrucci
After an “intensive survey of its natural habitat,” the Yangtze River dolphin has been officially declared extinct. So if, as a person, you ever wanted to see one alive, you’re out of luck. And if, as a Yangtze River dolphin, you ever wanted to be alive, also, you’re out of luck.

From a population of thousands in the 1950s, human activity reduced the Yangtze River, or Baiji, dolphin to just a handful of individuals by the turn of the century. Industrialization of the Yangtze River, unsustainable fishing practices, and mass shipping, rather than direct human persecution, placed the Baiji dolphins under extreme pressure, and now they’re all dead, forever. An article in The Guardian states that this is “the fourth time an entire evolutionary line of mammals has vanished from the face of the Earth since the year 1500.” Quite an achievement.

Cross it off your list.

Dec
19
2006

Chinese river dolphin: extinct?
Chinese river dolphin: extinct?

An international team of scientists recently spent six weeks on China's Yangtze River looking for the endangered river dolphin. They were unable to find any, leading some to believe the animal has been driven to extinction.

The 8-foot-long mammal has lived in China's longest river for 20 million years. But massive increases in fishing, shipping and development have pushed the creature to the brink. The last confirmed sighting occurred in 2004, and the last captive dolphin died in 2002.

By definition, scientists don't consider an animal extinct until 50 years after the last sighting in the wild. And the recent survey focused on the river's main channel - it's possible some dolphins may yet hang on in the tributaries. But even if they do, it's unlikely the population can ever recover.

Nov
15
2006

Late last month, fishermen in Japan netted a surprise -- a bottlenose dolphin with two well-developed rear flippers. The flippers are remnants of the legs which grew in the dolphin's prehistoric ancestors.

Every animal's body is built by the genes contained in its DNA. But not all genes are active -- they have to be turned on by controller genes.

Over time, the DNA in a species changes -- new genes emerge, old ones become inactive. But in many cases, the old ones don't completely go away. The controller changes and stops activating the gene. But if there's a change in the controller, it may activate that forgotten gene again.

(The same thing happens with humans. As a baby develops inside its mother, it grows gills and a tail -- remnants of our animal heritage. These disappear before the baby is born.)

May
23
2006


What's my name?: Researchers have found out that dolphins create their own series of clicks and whistles to identify themselves much like the names we give ourselves. (Photo by sandor at morguefile.com)
You’ve got your Donald Duck, Mickey Mouse and Rocky the Squirrel. How about Diane the Dolphin?

The May edition of National Geographic reports that marine biologists have discovered that dolphins give themselves a unique name to identify themselves among their peers. It might not sound like our first names such as “Bob” or “Lisa,” but rather is a unique combination of whistles and clicks that single them out among the other dolphins in their group.

So how do scientists know this for sure? Afterall, there aren’t any humans who can speak dolphin, right?

The idea that dolphins have their own unique sounds for their name dates back in theory to 1991. But only recently have researchers been able to test out those ideas.

What they’ve done is take audio recordings of dolphin sounds collected over the past 30 years. Focusing their efforts on bottle-nosed dolphins found around Sarasota, Fla., researchers mimicked those recorded sounds with sounds made through keyboard synthesizers and then played back that new audio to the dolphins through underwater speakers.

What they discovered was that the Florida dolphins responded strongly to the sounds that were copies of sounds from other dolphins in their group and largely ignored the sound patterns from unfamiliar dolphins.

Furthermore, researchers also believe that young dolphins begin honing their listening skills, and developing their own unique vocal identification, early in life. It’s an especially important skill for bottle-nose dolphins since they live in large packs in sometimes murky waters. With a much more advanced social structure than other types of animals, dolphins may need to have better ways of finding each other when their separated.

Other interesting twists to the dolphin naming practices:

• Male dolphins are likely to choose a pattern of sound that is similar to their mother’s name sound.
• Dolphins love their names. Researchers have determined that they’ll say their names a lot when communicating with other dolphins, for instance saying “Diane caught a fish.”
• Other dolphins will mimic a peer’s name sound patterns to get that dolphin’s attention.

More information about dolphin naming practices can be found at http://news.nationalgeographic.com/news/2006/05/060508_dolphins.html

And for all you football fans reading this, there’s no word in the research if any new dolphins have taken the name Daunte.