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Tree of Life
Plant Flower, Tree
Invertebrate Octopus, Ant, Bee, Butterfly, Spider, Lobster
Vertebrate Fish, Seahorse, Ray, Shark, Frog, Turtle, Tortoise, Dinosaur
Bird, Ostrich, Owl, Crow, Parrot
Mammal Bat, Rabbit, Giraffe, Camel, Horse, Elephant, Mammoth
Whale, Dolphin, Walrus, Seal, Polar Bear, Bear, Cat, Tiger, Lion, Dog, Wolf
Monkey, Chimpanzee, Human
These are organized by a classification scheme developed exclusively for Cosma. More…
dolphin : any of various small marine toothed whales (family Delphinidae) with the snout more or less elongated into a beak and the neck vertebrae partially fused
Note: While not closely related, dolphins and porpoises share a physical resemblance that often leads to misidentification. Dolphins typically have cone-shaped teeth, curved dorsal fins, and elongated beaks with large mouths, while porpoises have flat, spade-shaped teeth, triangular dorsal fins, and shortened beaks with smaller mouths. — Webster
Dolphins are a widely distributed and diverse group of aquatic mammals. They are an informal grouping within the order Cetacea, excluding whales and porpoises, so to zoologists the grouping is paraphyletic. The dolphins comprise the extant families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the new world river dolphins), and Pontoporiidae (the brackish dolphins), and the extinct Lipotidae (baiji or Chinese river dolphin). There are 40 extant species of dolphins. Dolphins, alongside other cetaceans, belong to the clade Cetartiodactyla with even-toed ungulates. Their closest living relatives are the hippopotamuses, having diverged about 40 million years ago.
Dolphins range in size from the 1.7 m (5.6 ft) long and 50 kg (110 lb) Maui’s dolphin to the 9.5 m (31 ft) and 10 t (11 short tons) killer whale. Several species exhibit sexual dimorphism, in that the males are larger than females. They have streamlined bodies and two limbs that are modified into flippers. Though not quite as flexible as seals, some dolphins can travel at 55.5 km/h (34.5 mph). Dolphins use their conical shaped teeth to capture fast moving prey. They have well-developed hearing which is adapted for both air and water and is so well developed that some can survive even if they are blind. Some species are well adapted for diving to great depths. They have a layer of fat, or blubber, under the skin to keep warm in the cold water.
Although dolphins are widespread, most species prefer the warmer waters of the tropic zones, but some, like the right whale dolphin, prefer colder climates. Dolphins feed largely on fish and squid, but a few, like the killer whale, feed on large mammals, like seals. Male dolphins typically mate with multiple females every year, but females only mate every two to three years. Calves are typically born in the spring and summer months and females bear all the responsibility for raising them. Mothers of some species fast and nurse their young for a relatively long period of time. Dolphins produce a variety of vocalizations, usually in the form of clicks and whistles. — Wikipedia
Dolphins and Whales News -- ScienceDaily Whales and dolphins. Whale songs, beaching, endangered status -- current research news on all cetaceans.
- Reprogrammed whale neurons predict neurotoxicity...on July 27, 2021 at 4:12 pm
A research team has directly reprogrammed whale somatic cells to neuronal cells, and conducted a neurotoxicity test using these cells. Exposure to a metabolite (4?OH-CB72) of polychlorinated biphenyls, ubiquitous environmental pollutants, caused apoptosis in the reprogrammed neurons. Transcriptome analysis of 4?OH-CB72-treated whale neurons showed altered expressions of genes associated with oxidative phosphorylation, chromatin degradation, axonal transport, and neurodegenerative diseases.
- New evidence of menopause in killer whaleson July 20, 2021 at 7:12 pm
Scientists have found new evidence of menopause in killer whales - raising fascinating questions about how and why it evolved.
- Social secrets of killer whales discovered using...on June 16, 2021 at 11:15 pm
Killer whales have complex social structures including close 'friendships', according to a new study that used drones to film the animals.
- Bycatch risk for dolphins and porpoises in global...on June 15, 2021 at 5:21 pm
Marine scientists assessed the risk posed by small-scale fisheries to all 72 species of toothed whales found throughout the world's oceans. They found that this risk was highest in the Central Indo-Pacific, Temperate Northern Pacific, Temperate South America and the Western Indo-Pacific.
- Endangered blue whales recorded off southwest...on June 10, 2021 at 1:11 pm
Underwater recordings show that endangered blue whales are present and singing off the southwest coast of India. This extends the range of a known song type by 1,000 kilometers, into Indian waters. The results suggest that conservation measures should include this region.
Phys.org - latest science and technology news stories Phys.org internet news portal provides the latest news on science including: Physics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine.
- Baby orca dies in New Zealand after fruitless...on July 24, 2021 at 8:26 am
Toa, the baby orca who captured hearts after he was found stranded in New Zealand waters, has lost his fight for survival, conservationists confirmed Saturday.
- The science of underwater swimming: How staying...on July 23, 2021 at 3:00 pm
To win swimming gold in Tokyo, swimmers not only have to generate incredible power with their arms and legs to propel themselves through the water; they also have to overcome the relentless pull of the water's drag while doing so.
- Scientists need your help to spot blue whales off...on July 21, 2021 at 12:54 pm
Blue whales, the largest animals ever to live, are surprisingly elusive.
- High-ranking hyena mothers pass their social...on July 15, 2021 at 6:00 pm
Hyenas are a highly social species, living in groups that can number more than 100. But within their clans, there is order: A specific matrilineal hierarchy governs societies in this species where females are dominant to males.
- Foe to friend: Fishermen join fight to save...on July 15, 2021 at 7:40 am
Freshwater dolphins are flourishing in a stretch of Pakistan's main river after a helping hand from fishermen mobilised to defend a rare species driven to near-extinction.