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.
Early dispersal for quadrupedal cetaceans:...
on November 8, 2019 at 10:16 pm
Scientists have a relatively precise idea about where whales and their closest terrestrial relatives evolved more than 50 million years ago (early Eocene), thanks to the discovery of ancient cetacean fossils in India and Pakistan. Around 45 million years ago, four-legged whales (protocetids) gradually dispersed out of Asia, westward towards Africa and then reached the east coast of North America more than 41 million years ago.
Dolphins demonstrate coordinated cooperation
on October 28, 2019 at 2:38 pm
Researchers investigated the cooperative abilities of dolphins. Utilizing a simplified Hirata Task, the team found that dolphins coordinated their behavior to work together on a shared task. Specifically, the 'initiator' would wait on their partner and the 'follower' would coordinate their swimming speed to match the initiator's behavior.
Genetics reveal pacific subspecies of fin whale
on October 28, 2019 at 1:24 pm
New genetic research has identified fin whales in the northern Pacific Ocean as a separate subspecies, reflecting a revolution in marine mammal taxonomy as scientists unravel the genetics of enormous animals otherwise too large to fit into laboratories.
Humpback whale population on the rise after near...
on October 21, 2019 at 8:11 pm
A new study finds that the western South Atlantic humpback population has grown to 25,000 whales. Researchers believe this new estimate is now close to pre-whaling numbers.
Stranded whales detected from space
on October 17, 2019 at 6:11 pm
A new technique for analysing satellite images may help scientists detect and count stranded whales from space. Researchers tested a new detection method using Very High Resolution (VHR) satellite images of the biggest mass stranding of baleen whales yet recorded. It is hoped that in the future the technique will lead to real-time information as stranding events happen.
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Bats don't rely on gut bacteria the way humans do
on November 12, 2019 at 7:10 pm
Right now, there are trillions of bacteria living in your gut, making up about one percent of your body weight. They're supposed to be there—we need them to help us digest food and fight off diseases. The same is true for most mammals; in general, just about every mammal from dogs to dolphins relies on a community of helpful bacteria, called a microbiome, living inside them for health and survival. Many animals have even evolved along with their gut bacteria to better work together, to […]
Early dispersal for quadrupedal cetaceans:...
on November 9, 2019 at 11:15 am
Scientists have a relatively precise idea about where whales and their closest terrestrial relatives evolved more than 50 million years ago (early Eocene), thanks to the discovery of ancient cetacean fossils in India and Pakistan. Around 45 million years ago, four-legged whales (protocetids) gradually dispersed out of Asia, westward towards Africa and then reached the east coast of North America more than 41 million years ago. Due to the relatively fragmentary fossil record on both sides of the […]
'Ghost' fishing gear: the trash haunting ocean...
on November 6, 2019 at 8:21 am
Far out in the South Atlantic Ocean, invisible to the South African coastline, diver Pascal Van Erp surfaced with an abandoned lobster cage covered in algae and other marine organisms.
Complex society discovered in the vulturine...
on November 4, 2019 at 4:00 pm
Multilevel societies have, until now, only been known to exist among large-brained mammals including humans, other primates, elephants, giraffes and dolphins. Now, scientists from the Max Planck Institute of Animal Behavior and the University of Konstanz report the existence of a multilevel society in a small-brained bird, the vulturine guineafowl (Acryllium vulturinum). The study, published in Current Biology, suggests that the birds can keep track of social associations with hundreds of other […]
Echolocation found to be cheap for deep-diving...
on November 1, 2019 at 1:46 pm
A new international study led by Aarhus University in Denmark, in collaboration with the Universities of St Andrews and La Laguna, Tenerife, reveals how whales have evolved to live in the world's deepest oceans.