Dolphins -True or false?

The skin of dolphins and sharks is almost the same .

FALSE. Shark skin is covered with very hard scales, while dolphin skin is extremely smooth and delicate.The dolphin hears ultrasound with its jaw. 

The dolphin hears ultrasound with its jaw.

TRUE. Like the bat, the dolphin emits ultrasound. It captures the ultrasonic echo with the bones and fat of its lower jaw, which are connected to the inner ear.

Killer whales (Orcas) are the biggest animals that hunt in groups. 

TRUE. On the open sea, killer whales hunt in groups of several dozen. Nearer the coast, groups are reduced 5 or 6 hunters.

 

A bottlenose dolphin eats 10 to 22.5 kg of fish a day.

TRUE. On average, an adult bottlenose dolphin eats the equivalent of 4 to 9% of its weight each day.

Dolphins call each other by name.

TRUE. Dolphins let out very specific whistles. These short bursts of audible sound are used, among other things, to identify oneself. Indeed, each dolphin has its own distinctive whistle.

Dolphins rely very much on their sense of smell.

FALSE. Dolphins have a very weak sense of smell. By contrast, they have excellent eyesight and a highly developed echolocation (sonar) system.

The spinner dolphin and the killer whale are both able to jump more than (7 m) out of the water.

TRUE. The spinner dolphin and killer whale are both able to jump more than 23 ft. (7 m) out of the water. They sometimes do acrobatics whose meaning is still mysterious.

Dolphins drink 10 liters of water per day. 

FALSE. Dolphins do not drink water. Their kidneys are unable to filter sea salt. They take in the liquid they need from the fish they eat.

Freshwater dolphins can turn their head 90°. 

TRUE. River dolphins have a very flexible spine that allows them to turn their head at an angle of 90°. This feature is very useful to them when they need to make turns in a narrow watercourse.

Dolphins can swim at a speed of 25 mph (40 km/h).

TRUE. Dolphins are very fast marine mammals. The smallest species reach a top speed of 25 mph (40 km/h) and the most impressive, the killer whale (orca), exceeds 35 mph (55 km/h).

The killer whale (orca) is twice as big as an elephant.

TRUE. The killer whale, also called orca, is the largest member of the dolphin family. This giant of the seas is 30 ft. (9 m) and weighs 10  tons.

Dolphins sleep with only one side of their brain at a time.

TRUE: To prevent itself from drowning to death, a dolphin rests only one side of its brain at a time. While one hemisphere is sleeping, the other controls its breathing and ensures that its body remains at the water surface. Thanks to this technique, a dolphin can wake up quickly in case of danger.

When its blowhole has problems, the dolphin can breathe through its mouth.

FALSE. The digestive and respiratory tracts in dolphins are separated hermetically. Dolphins can’t breathe through their mouth as do terrestrial mammals.

Dolphins have many teeth that help them to chew their food.

FALSE. Dolphins’ teeth are ideal for capturing prey such as fish, but they do not allow dolphins to chew. Dolphins swallow their prey whole

Sea salt can make dolphins blind.

FALSE. Glands secrete a thick, oily liquid that continuously covers the surface of the eyes to protect them from the salt.

There are no bottlenose dolphins in the Mediterranean Sea.

FALSE. The population of bottlenose dolphins in the Mediterranean is estimated at about 10,000.

Killer whales leap into the air in order to catch flying birds.

FALSE. Killer whales can leap over 23 ft. (7 m) high but nobody knows why they do this; however it certainly isn’t to catch birds in flight.