Note: These are 360° videos — press and hold to explore them!
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…
shark : any of numerous mostly marine cartilaginous fishes of medium to large size that have a fusiform body, lateral branchial clefts, and a tough usually dull gray skin roughened by minute tubercles and are typically active predators sometimes dangerous to humans — Webster
Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha (or Selachii) and are the sister group to the rays. However, the term “shark” has also been used for extinct members of the subclass Elasmobranchii outside the Selachimorpha, such as Cladoselache and Xenacanthus, as well as other Chondrichthyes such as the holocephalid eugenedontidans. Under this broader definition, the earliest known sharks date back to more than 420 million years ago. Acanthodians are often referred to as “spiny sharks”; though they are not part of Chondrichthyes proper, they are a paraphyletic assemblage leading to cartilaginous fish as a whole.
Since then, sharks have diversified into over 500 species. They range in size from the small dwarf lanternshark (Etmopterus perryi), a deep sea species of only 17 centimetres (6.7 in) in length, to the whale shark (Rhincodon typus), the largest fish in the world, which reaches approximately 12 metres (40 ft) in length. Sharks are found in all seas and are common to depths of 2,000 metres (6,600 ft). They generally do not live in freshwater although there are a few known exceptions, such as the bull shark and the river shark, which can survive and be found in both seawater and freshwater. Sharks have a covering of dermal denticles that protects their skin from damage and parasites in addition to improving their fluid dynamics. They have numerous sets of replaceable teeth.
Well-known species such as the great white shark, tiger shark, blue shark, mako shark, thresher shark, and the hammerhead shark are apex predators—organisms at the top of their underwater food chain. Many shark populations are threatened by human activities. — Wikipedia
10 Best Places to Swim With Sharks (Professional Association of Diving Instructors, Condé Nast Traveler)
25 Best Destinations for Sharks and Adventure (Travis Marshall, Scuba Diving)
Shark Diving Tips and Advice (Shart Trust)
10 Shark Diving Tips (Dive Magazine)
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.
New device to be tested off Outer Banks could...
on October 18, 2019 at 5:10 pm
An Outer Banks fisherman next summer will test a device about the size of a spark plug that could save rare sharks.
Galapagos study highlights importance of...
on October 16, 2019 at 4:43 pm
As the world's climate continues to change, biologically diverse communities may be most capable of adapting to environmental challenges.
Thames Humpback whale killed by ship: The...
on October 16, 2019 at 2:18 pm
A humpback whale was recently spotted in the River Thames near London. This unusual sighting sparked national media interest, similar to "Benny" the beluga who also called the river home for several weeks last year. However, while Benny eventually left the Thames and headed home to the Arctic, the humpback whale was not so lucky. Ironically, despite the human-interest factor, the whale died as a result of human impact. In doing so, it had the dubious honor of being the first humpback whale […]
Best way to protect ocean fisheries? Let nations...
on October 14, 2019 at 11:56 am
Overfishing is a major problem for the world's oceans, but a strategy adopted nearly 50 years ago has helped protect fisheries: giving nations exclusive rights to waters 200 miles offshore and letting them police their own fish stocks.
Crowdsourcing consumer loans can bolster business...
on October 11, 2019 at 10:49 am
Imagine being able to borrow money from strangers, but without the potential of getting your thumbs broken if you miss a payment.
For sea creatures, baseline shows disease as...
on October 10, 2019 at 7:22 am
The health of Earth's oceans is rapidly worsening, and newly published Cornell-led research has examined changes in reported diseases across undersea species at a global scale over a 44-year period.
Fossil fish provides new insights into the...
on October 2, 2019 at 3:55 pm
An international research team led by Giuseppe Marramà from the Institute of Paleontology at the University of Vienna discovered a new and well-preserved fossil stingray with an exceptional anatomy, which greatly differs from living species. The find provides new insights into the evolution of these animals and sheds light on the recovery of marine ecosystems after the mass extinction occurred 66 million years ago. The study was recently published in the journal Scientific Reports.
Technology provides insight into the hunting...
on October 2, 2019 at 2:39 pm
White sharks are top predators in the marine environment, but unlike their terrestrial counterparts, very little is known about their predatory activity underwater, with current knowledge limited to surface predation events. Now, a team of international scientists has used video- and data-logging technology to shed new light on predator-prey interactions of these mighty sea creatures.
First skeletal remains of Phoebodus found in...
on October 2, 2019 at 12:30 pm
An international team of researchers has found the first skeletal remains of Phoebodus—an ancient shark—in the Anti-Atlas Mountains in Morocco. In their paper published in Proceedings of the Royal Society B, the group describes the fossil and compares it to a modern shark and fish.
How sustainable is tuna? New global catch...
on October 1, 2019 at 5:03 pm
Appearing in everything from sushi rolls to sandwiches, tuna are among the world's favourite fish. But are our current tuna fishing habits sustainable?