Q.  How many species of dolphins are there in the world?

A:  There are 33 species in the dolphin family. Dolphin species vary in size from the Hector dolphin (approximate length 1.3 meters) to the Orca or Killer whale (approximate length up to 9 meters).

Q.  Do dolphins sleep?

A:  Like every mammal, dolphins need to sleep. Since underwater life requires breathing control, dolphins have developed a special way to sleep. The two halves of the brain sleep independently, and never simultaneously. In this way, one side can always control breathing, while the other controls basic behavioral patterns.

Q.  Why don't dolphins get cold during the winter or hot during the summer?

A:  Who said dolphins don't get cold? In the wintertime, just as land mammals grow thick fur, dolphins increase the thickness of their insulating layer of fatty tissue (blubber).

Q.  Are there dolphins in the Red Sea?

A:  There are at least 9 dolphin species native to the Red Sea. The false killer whale grows to a length of almost 6 meters, but most Red Sea dolphins belong to smaller species. Most common are spotted dolphins (about 2 meters) and bottlenose dolphins (about 2.5 meters).

Q.  How do dolphins behave during and after birth?

A:  After a gestation of 12 months, a single dolphin calf is born tail first. Labor can last up to 2.5 hours, and the female in labor may be accompanied by an assisting animal during and after delivery. Other members of the group have been observed approaching mother and calf shortly after birth. The calf nurses for about 18 months, but may stay close to its mother for up to 6 years.

Q.  Does an entire dolphin group help to raise the calves, and if so, how?

A:  Even early in life, there is close contact and interaction between newborn calves and other group members, which we think helps the calves learn social skills. The assistance of other animals may also aid dolphin mothers in foraging.

Q.  How do we know that dolphins used to live on land?

A:  Anatomically, dolphins still possess the main features of land mammals, such as skeletal structure and the location of internal organs. Dolphins even have hair, one of the main characteristics that mammals developed on land, though dolphin hair is minimal. The fossil record reveals the evolutionary stages from four-legged land mammals to marine mammals with reduced extremities.

Q.   What abilities did dolphins develop in order to adapt to life in the water?

A:  Dolphins underwent many physiological and morphological changes, among which are: the streamlining of the overall body shape, development of a layer of insulating fatty tissue (blubber), and an increase in muscular oxygen storage capacity. One major anatomical change was the repositioning of the nasal opening to the top of the head, now termed the "blowhole" in dolphins and whales.

Q.   Is the dolphin a fish?

A:  No, the dolphin is a sea mammal.

Q.  What makes a dolphin a mammal?

A:  Dolphins are warm-blooded, bear live young, suckle their babies, and breathe air with their lungs.

Q.  What is a dolphin's life expectancy?

A:  It depends on the species of dolphin. Bottlenose dolphins live between 35 and 40 years.

Q.   To what depth do dolphins dive?

A:  It depends on the species of dolphin. Most can dive to around 300 meters.

Q.  For how long can a dolphin hold its breath?

A:  It depends on the species of dolphin. Bottlenose dolphins can dive for about 30 minutes.

Q.  How fast do dolphins swim?

A:  It depends on the species of dolphin. Bottlenose dolphins can swim between 40 and 60 kilometers an hour.

Q.  How does the blowhole work?

A:  The blowhole, situated on top of the dolphin's head, is actually the nasal opening. It is surrounded by strong muscles that ensure its closure during diving. When the dolphin surfaces, the blowhole opens to allow exhaling and inhaling. The dolphin cannot breathe through its mouth.

Q.  What is the weight and length of a dolphin?

A:  An adult Bottlenose dolphin is between 1.9 and 4.5 meters long, and weighs between 150 and 650 kilograms.

Q.  What is the significance of the dolphin's tail movements?

A:  Fish tails move from side to side. Dolphins, like other sea mammals, move their tails up and down.

Q.  How long can a dolphin live out of the water?

A:  In principle, a dolphin can live for many hours out of the water, since, like humans, it breathes with its lungs. However, a dolphin's skin must be kept damp at all times. In addition, its body must be cooled by pouring ice water on its flippers, which carry numerous blood vessels just below the surface of the skin. Finally, when a dolphin lies on the ground, as opposed to floating in the water, pressure is created on its internal organs, which can cause general stress and difficulty.

Q.  Which parts of the dolphin's body are most sensitive?

A:  The sensitive parts of a dolphin's body are its eyes, air hole, sex organs, and tail.

Q.  How many teeth does a dolphin have?

A:  Between 80 and 100.

Q.  Does a dolphin lose old teeth and grow new ones?

A:  No. The dolphin keeps its teeth for its whole life.

Q.  At what age does a dolphin reach sexual maturity?

A:  The females reach sexual maturity at about eight years of age, and the males at about twelve years.

Q.  How can you tell a male dolphin from a female?

A:  The male dolphin has two slits in its lower belly, one for its penis and the other for its anus. The female dolphin has only one slit, which contains both the anus and the vagina.

Q.  How do dolphins copulate?

A:  They copulate underwater, while swimming, lying belly to belly. The male inserts his penis into the female's vagina for several seconds. The male sex organ is controlled by a muscle.

Q.  When do dolphins copulate?

A:  Dolphins copulate for pleasure all year round. There are certain months of estrus during which the females can become pregnant.

Q.  What is sonar and how does it work?

A:  Sonar is a sensory system which dolphins use to explore their environment. The dolphin emits specific sounds (clicks), which bounce off objects in its path. The echo is received and processed by the dolphin into a three-dimensional picture of an object.

Q.  Where is the male dolphin's sex organ located?

A:  It is located in its lower belly. It is an internal organ, and the male dolphin brings it out with a special muscle for mating.

Q.  For how many months do dolphins gestate?

A:  Gestation lasts for about one year.

Q.  How does the female dolphin behave during labor?

A:  The female dolphin generally swims near the surface of the water, in order to allow the newborn to more easily get its first breath of air. Before birth, she swims over and over on the same path through the water.

Q.  Where does the dolphin give birth - on the surface of the water, or deeper down?

A:  Just below the surface of the water.

Q.  How often can a dolphin become pregnant?

A:  Approximately every two to three years.

Q.  How many babies can a dolphin bear at once?

A:  A dolphin bears a single calf at each birth.

Q.  How long does birth last?

A:  Birth can last for an hour or two. It is thought best if labor lasts for 45 to 60 minutes.

Q.  How and where does the baby dolphin nurse?

A:  The baby dolphin nurses from its mother through two nipples located in the mother's lower belly, near her sex organs. The baby nurses underwater by pressing on the nipples, which spurt milk into its mouth. The baby has no lips with which to suck, so it must nurse by pressing down.

Q.  For how long does the baby nurse from its mother?

A:  This depends on the bond between the baby and its mother. The average is a year and a half.

Q.  For how long does the calf stay close to its mother?

A:  This depends a lot on the individual calf and mother. There are certain mothers who tend to worry a lot and stick close to their calves for a long time. However, the average is about a year and a half.

Q.  Why do dolphins have sonar and what do they use it for?

A:  As an adaptation to life in the water, where vision can be extremely limited, dolphins developed this unique sense to explore their environment. Specifically, sonar is used for orientation, detection of prey and predators, and possibly to stun prey during foraging.

Q.  How does the rest of the group treat the calf?

A:  The mother raises her calf with the help of others. When she wants to rest, young female dolphins serve as babysitters. The whole group teaches the calf to fish, swim, copulate, and communicate.

Q.  At what age does the dolphin start eating fish?

A:  Usually at about four months, but it continues to nurse for a year and a half, on the average.

Q.  What senses does a dolphin have?

A:  A dolphin has all of the senses humans do, except for the sense of smell.

Q.  Can dolphins see?

A:  Yes, very well.

Q.  Do dolphins have ears? Where are they, and what do they look like?

A:  The dolphin has two ears and excellent hearing. Its ears are located behind its eyes. To an onlooker, they appear to be two little holes about the size of a pin.

Q.  How can you tell that a dolphin is sick?

A:  Sick dolphins usually stop eating, lose weight, and hardly swim at all, preferring to float instead. They also breathe more rapidly.

Q.  How can you tell what disease a dolphin has?

A:  The most efficient way is by testing the blood, stool, digestive juices, and breath. In some cases, it is enough for us to carefully watch for signs that are familiar to us from previous cases.

Q.  How do you care for a sick dolphin?

A:  Treatment varies. There are cases which require isolation from the rest of the group, such as contagious diseases. Most treatments use the same medications used for human illnesses, such as antibiotics.

Q.  What diseases can a dolphin get?

A:  They can suffer from the same diseases that people do. The most common are respiratory, skin, and digestive diseases.

Q.  How do dolphins produce sounds?

A:  Dolphins do not have vocal cords. Sounds are produced by a system of air sacs situated just below the blowhole. Air is moved between air sacs through valves (called "nasal plugs"), thereby creating a variety of sounds, which are transmitted into the water through the forehead.

Q.  What do dolphins eat?

A:  Dolphins eat saltwater fish and cephalopods, such as squid or octopus.

Q.  How much do dolphins eat?

A:  Each dolphin eats according to its size and appetite. On the average, an adult dolphin eats about 12-15 kilograms of food a day.

Q.  Do dolphins swallow their food whole, or chew it?

A:  The dolphin swallows the fish, which is digested in its stomach.

Q.  If a dolphin doesn't chew, why does it need teeth?

A:  The dolphin uses its teeth for hunting, and sometimes also for self-defense.

Q.  Do dolphins fight with each other?

A:  Absolutely. Sometimes they fight for fun, but sometimes they fight over females, or to get attention.

Q.  How do the males relate to each other?

A:  The males protect the group. The young males constitute a certain threat to the adult, breeding male, and there may be battles for the position of dominant breeder.

Q.  Are dolphins naturally friendly to humans?

A:  Even in nature, dolphins have been seen approaching ships and fishing vessels, apparently out of curiosity and interest.

Q.  Could a dolphin attack a person?

A:  There are no known cases of dolphins attacking humans - dolphins by nature are not aggressive. If a human bothers a dolphin, the dolphin simply swims away from him or her.

Q.  Do dolphins mate for life?

A:  No, dolphins live in a sort of harem - a single male copulates with and impregnates a number of females.

Q.  Is physical contact important for dolphins?

A:  Yes, especially in terms of comfort, pleasure, scratching, and sexual stimulation.

Q.  Which are more intelligent, dolphins or humans?

A:  This question is impossible to answer, as there are no objective criteria for defining intelligence, especially when comparing entire species.

Q.  Why are dolphins killed in Japan?

A:  Japanese fishermen consider them to be competitors. They believe that by killing dolphins, they increase the supply of fish.

Q.  Why isn't the killing of dolphins stopped?

A:  This would be a difficult task for a number of reasons. First of all, global water pollution directly affects the dolphins' quality of life. Commercial fishermen also cause great harm to the dolphin population; these fishermen represent a group with considerable political and financial resources.

Q.  In which seas are dolphins found?

A:  In all the seas of the world, and in rivers as well.

Q.  Do dolphins live in a group?

A:  Yes, the social life of dolphins is very important to their survival.

Q.  What is the social structure of the group?

A:  In general, a group of dolphins consists of a dominant male, adult females, and calves (babies). The young males swim together at some distance from the rest of the group. When a young male feels strong enough, he tries to take the place of the dominant male.

Q.  Is dolphin language the same all over the world, or does it vary?

A:  We do not yet know enough about dolphin language. We still don't understand the structure of their communication, so we can't compare different regions.

Q.  Is a dolphin's brain bigger or smaller than ours?

A:  Comparing absolute size and weight, the average bottlenose dolphin brain is about 20% bigger than the average human brain. In general, it is more informative to include additional measurements in these comparisons, such as the extent of cortex convolution, or the ratio of brain volume to body surface area (the encephalization quotient).