Sea animals questions

The spotted eagle ray (Aetobatus narinari) is a cartilaginous fish of the eagle ray family, Myliobatidae. This ray can be identified by its dark dorsal surface covered in white spots or rings. The rays are considered near threatened on the IUCN Red List. They are fished mainly in Southeast Asia and Africa, the most common market being in commercial trade and aquariums. They are protected in the Great Barrier Reef.

A blue whale's tongue weighs around 2.7 tonnes (3.0 short tons) and, when fully expanded, its mouth is large enough to hold up to 90 tonnes (99 short tons) of food and water.

Māui's dolphin or popoto (Cephalorhynchus hectori maui) is the world's rarest and smallest known subspecies of dolphin. Māui's dolphins are only found off the west coast of New Zealand's North Island.

The sea swallow, blue angel, is a species of small, blue sea slug. These sea slugs are pelagic: they float upside down by using the surface tension of the water to stay up, where they are carried along by the winds and ocean currents. Glaucus atlanticus feeds on other pelagic creatures, including the venomous siphonophore and the Portuguese man o' war.

Clocked at speeds in excess of 68 mph, some experts consider the sailfish the fastest fish in the world. Easily recognized, sailfish are named for the spectacular sail-like dorsal fin that extends for nearly the entire length of their silver-blue body. Additionally, the sailfish's upper jaw is far longer than its lower jaw, forming a distinctive bill that looks like—and sometimes acts like—a spear.

The shrimp, called also Pink Floyd pistol shrimp, may be found in Pacific waters at Panama coast. The sound of its snapping claw shut reaches 210 decibels (while whales achieve 188 decibels), and can kill passing nearby small fish. It is probably the loadest sound an animal creates.

Seahorse males deliver the babies. After mating, the fertilized eggs are embedded in the pouch wall and become surrounded by a spongy tissue. The male provides oxygen and supplies the eggs with prolactin, the same hormone responsible for milk production in pregnant mammals.

Although seahorses are bony fish, they do not have scales, but rather thin skin stretched over a series of bony plates, which are arranged in rings throughout their bodies.

Their speed and vision leads some researchers to believe that box jellyfish actively hunt their prey. Since they have no brain, the mechanisms that could make it happen remain unknown.

Usually, males have a single long tusk, the canine on the left side of the upper jaw that projects through the lip and forms a left-handed helix. The tusk grows throughout life, reaching length of 3 m (10 ft). In some rare cases, both canines grow equally long, forming two tusks. In the Middle Ages, narwhal tusks were sold as unicorn horns.