1. What is a dolphin?
Dolphins are in fact small toothed whales. They are among the most intelligent creatures on the Earth.
2. Are dolphins fish?
No, they are not, though dolphins resemble fish in appearance. Dolphins are mammals, they are warm-blooded, they breathe with lungs, their young are live-born and dolphin mothers breastfeed their young with their mammary glands.
3. Do dolphins really smile all the time?
No, they do not. Dolphins cannot move their facial muscles as humans do and that is why a dolphin seems to be smiling even when it is injured or sick.
4. How many species of dolphins are there?
According to scientists, there are 32 sea species and 5 types of river dolphins.
5. How warm is a dolphin’s body?
Dolphins are warm-blooded mammals and their body temperature is around 36 degrees. To keep this temperature, their body has a thick layer of fat, just below the skin, called subcutaneous fat.
6. Do dolphins have bones?
Yes, they have. Dolphin bones are lighter than human’s because their inside is filled with fat.
7. Is it true that dolphins have more teeth than crocodiles?
If dolphins had dentists, they would have been keeping them quite busy! The extremely long jaws of the dolphins can contain from 100 to as many as 250 sharp white teeth.
8. Are there any dolphins’ relatives living on dry land?
Yes, there are. Dolphins’ closest relatives are the cow, the deer, and the swine; and the hippopotamus, as some scientists insist. And let’s not forget... people.
9. Is it true that once dolphins had legs?
Millions of years ago dolphins did have legs. If you make a close observation of a dolphin’s skeleton you will notice two small pelvic stick-like bones. These bones are the rudimentary remnants of hind legs with the help of which, scientists consider, dolphins’ ancestors once walked on dry land.
10. How long have dolphins been existing?
Whales and dolphins originated from terrestrial mammals, which later returned to live in the water. According to scientists they have been existing for sixty million years; according to others: thirty million years; and some third say ten million years.
11. How do dolphins breathe?
Dolphins do not have gills like fish, so they cannot breathe underwater. They have to emerge on the surface in order to breathe. Dolphins do not breathe through their mouths and they do not have nostrils as humans do. Instead, they have a breathing hole on the top of their heads, which they open and shut in order to breathe. Unlike with humans, breathing is a conscientious act with dolphins.
12. How many times and how do dolphins dive?
Dolphins are perfect divers. The deepest documented dive of a Bottlenose dolphin is 300 meters. It belongs to Tuffy, a Bottlenose dolphin trained by the US Navy. Some dolphins can reach depths of 900 meters and their cousins, the whales, can dive as deep as 1900 meters.
Before diving, dolphins saturate their body muscles with oxygen. They slow down their heartbeat to half its usual rate and the blood is directed to the brain, which helps to withstand the great water pressure and to feed all body organs with oxygen. Many of the dolphins, however, live in rather shallow waters. In the area of Sarasota Bay (USA), dolphins spend much of their time in waters shallower than two meters.
13. What makes dolphins jump?
There are many reasons for these wonderful jumps. Sometimes by jumping dolphins move faster and see farther so, they can spot schools of fish. Thus they take their prey by surprise. Sometimes a jump helps them shake off the parasites sticking to their skin. And sometimes they jump just for the pleasure of it!
In Dolphinarium Varna dolphins make incredible jumps: from a depth of 6 meters, they jump as high as 5 meters up in the air! And all this they do just for the excited applause of their happy audience!
14. How fast can dolphins swim?
Bottlenose dolphins swim at a speed of 5 to 12 kilometers per hour but they can reach a speed of 42 kilometers per hour.
15. It is true that dolphins hear with their jaws?
Dolphins, unlike us humans and all the other mammals, do not have external ears. They catch sounds through their lower jaw. A cavity filled with fat conducts the sound waves through the jaw to the bones of the middle ear and then to the center of hearing in the brain. The sound spreads 85 times faster in water than in air. In the thick water medium, the external ear becomes unnecessary; its function is taken by the skull bones. This wonderful “antenna” is 6 times more efficient than dog’s hearing. Dolphins can locate the of a sound with utmost accuracy and they can hear from a 1000-meter distance!
16. Can dolphins see in the dark?
Like bats, dolphins “see” through sounds. This ability is called echolocation: dolphins emit a series of sounds and listen to how they are reflected by fish, stones, corals, the seafloor or other objects. This way dolphins find food and can swim without bumping into obstacles standing in their way. This wonderful ability is called SONAR and makes dolphins unsurpassed masters of the sea.
Apart from that, when swimming underwater some dolphins emit very strong clicking sounds, which can kill any small fish or sepia located within the range of the sound. Then dolphins quickly swallow their stunned catch.
17. Do dolphins have colour vision?
We know with certainty that dolphins can distinguish some colours but no one has studied this ability yet with all dolphin species.
18. How do dolphins sleep?
As we know, dolphins live immersed in water but they have to maintain their consciousness awake in order to breathe. This means that they cannot fall deeply asleep because then they would... drown. Dolphins have resolved this problem by letting only one half of their brain fall asleep at a time. The other half stays awake to keep them alive. The two brain halves take turns of vigilance at about every two hours until the dolphin gets enough sleep.
Dolphins have different behaviour when sleeping. They may swim slowly and emerge to the surface now and then or take a rest on the water surface with their breathing hole open. Or, they may take a rest on the seafloor (in shallow waters)
19. How large is the dolphin’s brain?
One of the remarkable secrets of dolphins is their brain, a unique creation of nature. Let’s compare dolphin’s brain to the brains of other creatures similar in size and weight. A shark weighing 100 kilograms has a brain of only 20-50 grams. Crocodile’s and dog’s brain weighs about 100-200 grams. Primates or anthropoid apes have brains of 300 to 500 grams and the human brain weighs 1.5 kilograms. But what about dolphins? Their brain weighs up to 2 kilograms.
And this is not all. The dolphin’s brain has very well developed and very strongly folded cortex, which is evidence of complex and intelligent behaviour. According to scientists, the dolphin’s brain has 50% more cells than the human brain!
20. Do dolphins chew?
Though they have a mouth full of teeth, dolphins do not chew their food. They swallow it whole and then digest it in their stomach, which has three chambers. Teeth serve only to hold the catch securely and tear it to pieces.
21. How long do dolphins live?
In a natural environment, most dolphins live about 25 to 30 years but in dolphinariums, under the care of man, dolphins can live up to 50 years. And grampuses can live up to 80 years.
22. How many calves do dolphins deliver at one birth?
In the majority of cases, dolphins give birth to only one baby, just like humans. Sometimes they give birth to twins but normally only one calf survives.
23. What do the calves look like?
Dolphin calves look like miniature copies of adult dolphins. Sometimes their colour is slightly different or it may have spots, which disappear when the dolphin grows up.
24. Is it true that dolphins call each other by names?
Some scientists have noticed that dolphins communicate by whistling sounds and they use individualized “names” to recognize each other. They have special piercing calls like personal signatures, which serve to distinguish their friends in the group. Each dolphin chooses its whistling “signature”; this happens usually around the time of their first birthday.
25. How can you distinguish one dolphin from another in a family?
You can do this by their dorsal fins.
Scientists claim that a dolphin’s dorsal fin is as individual as a human face is.
26. Can dolphins speak?
This is one of the greatest unresolved mysteries about dolphins. Dolphins definitely communicate via sound, they understand each other and react to the signals of other dolphins.
There are three major obstacles to decipher the secret of dolphin communication:
- First: unlike humans and dogs, dolphins do not possess vocal cords; they produce sounds with their breathing hole.
- Second: their sounds are heard and distributed in two different media: air and water.
- Third: human ear can perceive only 20% of the sounds emitted by dolphins.
At this point, mathematics and computers come to our help. In dolphin-produced signals recorded with the help of intricate equipment, computers find mathematical regularities, which are typical only for the written language of man! The only thing we can so far understand is that dolphins exchange complex information through these curious cracking and whistling sounds.
You don’t believe it? Here is a funny story:
In an aquarium, two dolphins had been performing a joint acrobatic trick for years. However, one day their coach was away and he was replaced by a colleague. The performance started and then the coach noticed that one of the “performers” was rather uncertain in its act; it did not immediately obey instructions and did not jump as high as it usually did. And the second dolphin seemed to encourage its partner by clicking and whistling sounds. The coach was worried that the first dolphin might have fallen ill. Later he was amazed to learn that the aquarium staff had accidentally mixed up the performers and instead of the “established artist” let into the pool a very young and untrained dolphin.
The show was only saved by the fact that the other skilled performer managed to “explain” to the novice what it had to do.
27. Can dolphins talk over the telephone?
One of the greatest lovers and researchers of dolphins, Dr. John Lily, was the first to give dolphins a chance to talk over the telephone. In two distant pools separated by walls, a telephone line was built. It consisted of an underwater microphone for speaking and loudspeakers for listening. The moment Dr. Lily switched the line on, the dolphins started to actively exchange sounds. When he switched off the line the dolphins visibly calmed down and got silent. Scientists noticed that the dolphins talked in a “cultured” manner: while one of them was speaking the rest were silent and listening.