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.
Whales lost their teeth before evolving hair-like...
on November 29, 2018 at 7:24 pm
Rivaling the evolution of feathers in dinosaurs, one of the most extraordinary transformations in the history of life was the evolution of baleen -- rows of flexible hair-like plates that blue whales, humpbacks and other marine mammals use to filter relatively tiny prey from gulps of ocean water. Now, scientists have discovered an important intermediary link in the evolution of this innovative feeding strategy: an ancient whale that had neither teeth nor baleen. […]
Whale songs' changing pitch may be response to...
on November 28, 2018 at 11:21 pm
Blue whales have been dropping pitch incrementally over several decades, but the cause has remained a mystery. A new study finds a seasonal variation in the whales' pitch correlated with breaking sea ice in the southern Indian Ocean. The new research also extends the mysterious long-term falling pitch to related baleen whales and rules out noise pollution as the cause of the global long-term trend, according to the study's authors. […]
A bigger nose, a bigger bang: Size matters for...
on November 15, 2018 at 7:50 pm
A new study sheds light on how toothed whales adapted their sonar abilities to occupy different environments. The study shows that as animals grew bigger, they were able to put more energy into their echolocation sounds -- but surprisingly, the sound energy increased much more than expected. […]
Humpback whales come to the Mediterranean to...
on November 15, 2018 at 4:53 pm
Although the presence of humpback whales in the Mediterranean has been considered unusual, it is known that their visits have increased in the last 150 years. A recent study indicates that what motivates these cetacean mammals to enter these waters is the search for food. […]
Killer whales share personality traits with...
on November 15, 2018 at 3:46 pm
Killer whales display personality traits similar to those of humans and chimpanzees, such as playfulness, cheerfulness and affection, according to new research. […]
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Banned toxins passed from mother to young in...
on December 10, 2018 at 1:50 pm
Dolphins in the northern Adriatic contain high levels of PCBs – highly toxic chemicals banned in the 1970s and 1980s – and are passing the pollutant to their young, according to new research led by a marine scientist at the University of St Andrews. […]
Parrot genome analysis reveals insights into...
on December 6, 2018 at 5:36 pm
Parrots are famously talkative, and a blue-fronted Amazon parrot named Moises—or at least its genome—is telling scientists volumes about the longevity and highly developed cognitive abilities that give parrots so much in common with humans. Perhaps someday, it will also provide clues about how parrots learn to vocalize so well. […]
Acrobatic geckos, highly maneuverable on land and...
on December 6, 2018 at 4:00 pm
Geckos are renowned for their acrobatic feats on land and in the air, but a new discovery that they can also run on water puts them in the superhero category, says a University of California, Berkeley, biologist. […]
Technique inspired by dolphin chirps could...
on December 5, 2018 at 8:15 pm
When you deform a soft material such as Silly Putty, its properties change depending on how fast you stretch and squeeze it. If you leave the putty in a small glass, it will eventually spread out like a liquid. If you pull it slowly, it will thin and droop like viscous taffy. And if you quickly yank on it, the Silly Putty will snap like a brittle, solid bar. […]
Soft tissue shows Jurassic ichthyosaur was...
on December 5, 2018 at 6:00 pm
An ancient, dolphin-like marine reptile resembles its distant relative in more than appearance, according to an international team of researchers that includes scientists from North Carolina State University and Sweden's Lund University. Molecular and microstructural analysis of a Stenopterygius ichthyosaur from the Jurassic (180 million years ago) reveals that these animals were most likely warm-blooded, had insulating blubber and used their coloration as camouflage from predators. […]