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.
Beaked whales' incredible diving abilities...
on February 6, 2019 at 9:14 pm
A new study provides the first record of the diving behavior of Cuvier's beaked whales in US Atlantic waters. The species is Earth's deepest-diving mammal but spends very little recovery time at the surface. The new data, from 5,926 dives recorded off Cape Hatteras, N.C., shows them routinely diving more than a mile while holding their breath for over an hour. These whales push the limits of mammalian physiology. […]
Plastic in Britain's seals, dolphins and whales
on January 31, 2019 at 1:43 pm
Microplastics have been found in the guts of every marine mammal examined in a new study of animals washed up on Britain's shores. […]
Why do beaked whales return to a Navy sonar range...
on January 29, 2019 at 3:19 pm
Using data from underwater robots, scientists have discovered that beaked whales prefer to feed within parts of a Navy sonar test range off Southern California that have dense patches of deep-sea squid. A new study shows that beaked whales need these prey hotspots to survive, and that similar patches do not exist in nearby 'sonar-free' areas. […]
Humpback whales' songs at subarctic feeding areas...
on January 23, 2019 at 1:22 pm
Humpback whales overwintering in feeding areas may sing complex, progressive songs which closely resemble those associated with breeding grounds, according to a new study. […]
Piece to the puzzle of baleen whales' evolution
on January 22, 2019 at 3:45 pm
A researcher has added another piece to the puzzle of the evolution of modern baleen whales with a new study examining the teeth and enamel of baleen whales' ancestors. […]
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Activists file suit to stop dolphin hunting in...
on February 14, 2019 at 8:23 am
Environmental campaigners have filed an unprecedented lawsuit in a bid to halt the so-called "drive hunting" of dolphins in Japan, arguing the practice is cruel and illegal. […]
Giant 'megalodon' shark extinct earlier than...
on February 13, 2019 at 11:00 am
Megalodon—a giant predatory shark that has inspired numerous documentaries, books and blockbuster movies—likely went extinct at least one million years earlier than previously thought, according to new research published Feb. 13 in PeerJ—the Journal of Life and Environmental Sciences. […]
Marine life typically thrives in the tropics –...
on February 12, 2019 at 3:29 pm
Life in the sea isn't easy. Talk to most people about the ocean and they are likely to imagine a tropical scene with a stretch of golden sand and warm, clear water. The reality is often quite different – the marine environment can be a surprisingly cold place. […]
Shark Bay: A World Heritage Site at...
on February 8, 2019 at 12:06 pm
The devastating bleaching on the Great Barrier Reef in 2016 and 2017 rightly captured the world's attention. But what's less widely known is that another World Heritage-listed marine ecosystem in Australia, Shark Bay, was also recently devastated by extreme temperatures, when a brutal marine heatwave struck off Western Australia in 2011. […]
Arizona facility temporarily closing after 4th...
on February 6, 2019 at 7:41 am
After the death of a fourth dolphin, a Phoenix-area aquatic facility announced Tuesday that it will temporarily close for a reevaluation by an outside panel of experts. […]