FAQS

Some people have contacted me wanting to know the answers to their dolphin questions. Below is a list of some of these questions and a few others too. If you have a question that you would like answered then please contact me and I will do my best to answer you.

Q: Do dolphins, being mammals, have any type of hair or fur on their bodies?
Dolphins are marine mammals and share several common characteristics among most mammals, one of which is the presence of hair. Some species of dolphin have hair when they are born, but not all species are born with hair. In the womb dolphins have a few whiskers around their snout and jaw bone, but this falls off and disappears entirely within a short amount of time.  Dolphins do not even have eye lashes, they have a layer of skin which is insulated with their blubber.
For more information on dolphin anatomy go to our anatomy  page

Q:  Where do dolphins live?
This depends on the species and time of year. Dolphins can be found almost anywhere in the world. While different species tend to be found in certain areas they may only be present at certain times of the year. Most dolphins prefer tropical and temperate waters as they are warm-blooded mammals and so it is easier for them to regulate their body temperature in these environments. Orcas are the only dolphins which live in the Arctic and Antarctic’s Southern oceans. Their large size means that they have more protection against the harsh cold of the freezing seas.
For more information on dolphin locations go to our location  page

Q: What are the differences between dolphins and porpoises?
Porpoises are smaller than dolphins; they are less than 2.5m (8ft) long. They are also characteristically chunkier than dolphins and have a small head, little or no beak, and a usually have a small triangular dorsal fin. Porpoises and dolphins also have a different teeth shape, with porpoise teeth are spade-shaped whilst dolphins are conical.

Q:  How are dolphins different from fish ?

• • • Dolphins and fish both have streamlined bodies and fins, but dolphins are mammals so they need regularly visit the surface to breathe air to survive. Fish extract oxygen from the water and do not need to surface. 

    • A dolphin’s tails move up and down as they swim, whereas a fish’s tail moves from side to side.

    • Dolphins are warm-blooded and have blubber to keep them warm. Fish are cold-blooded and are able to adjust to the different temperatures of the water without the need of body fat to keep them warm.

    • Most species of fish are also known to lay eggs and can lay hundreds of eggs in a single year. Dolphins give birth to a single baby once every 1 – 6 years and then feed their babies milk through their nipples.
      
      

Q: What is a dolphin's diet in the wild?
Dolphins eat a variety of different foods depending on amongst other things their size and whether or not they have teeth. Dolphins favour shoaling fish, such as anchovy and herring, but will also eat squid, shrimp and even jelly fish. It is difficult to define the precise diet and feeding behaviour of individual species but a rough guide for each dolphin species can be found on the 'Dolphin Characteristics Page . Each dolphin eats according to its size and appetite. On the average, an adult dolphin eats about 12-15kg (26-33lb) of food a day.
For further information about what dolphins eat go to 'Feeding strategy page'.

Q: Where are the mammary glands and how many breasts do dolphins have?
The mammary glands are two elongated, narrow and flat organs on either side of the vagina and the 2 nipples are located in slits. (In some embryos eight rudimentary nipples were found, suggesting ancestors may have had four pairs of nipples, and possibly produced multiple young). When suckling, the young approach from the rear. The mother will often turn to her side, to aid the youngster in finding the nipple. Because cetaceans do not have lips, the calf can’t suckle in the same way as terrestrial mammals. Instead, the calf grips the mother's now protruding nipple between its tongue and the roof of its mouth to make what it is believed a "tube". This speeds feeding, since the young cannot suckle for long periods due to the necessity to breathe. Cetacean milk is creamy white in colour, and may be tinted pink. It contains an unusually high percentage of fat, and a low sugar content. This may be due to the fact that the animal must develop quite quickly. A blue whale doubles it's birth weight in only 7 days, while a cow may take 50.
For more information on birth and life cycle go to our life cycle page.

Q:  What diseases do dolphins get?
Most dolphins tend to suffer from attacks by sharks and other dolphins or just old age. Very little is known about what diseases they suffer from but dolphins have been known to recover from even quite severe shark bites on their own with no human intervention. However, dolphins can suffer from the same diseases that people do. The most common are respiratory, skin, and digestive diseases.

Q:  Should dolphins be kept in captivity?
Whilst dolphins that have been kept in captivity can be studied and observed I am personally against it. Dolphins in captivity tend to be taken from the wild and many die a few weeks later due to the shock. Those that do become accustomed to life in a confined space tend to die at a much earlier age than if they were in the wild and some people have said that the dolphins "go senile" and should not be made to perform like circus animals.

Q: Do dolphins sleep?
Like every mammal, dolphins need to sleep. But the truth is that they do not really sleep at all - at least, not in the way that we do. Like humans, dolphins need to breathe air but since underwater life requires an element of breathing control, dolphins have developed a special way to sleep so that they can stay partly conscious, allowing them to continue breathing so that they do not drown. In other words they are 'conscious breathers' unlike us humans. While asleep, female dolphins lie on the water's surface and expose their blowholes to the air to breathe. Males however sleep just below the surface and a reflex action periodically raises their bodies. While dolphins 'sleep' they lie suspended at the water surface or swim along very slowly. The two halves of the brain sleep independently, and never simultaneously. One side of their brain stays awake to control breathing and look out for predators, whilst the other side relaxes. They don't sleep for long periods of time like we do - they seem to "cat nap" for short periods throughout the 24 hour cycle. In this fashion dolphins spend about one-third of their day ‘sleeping’ in short stints ranging from two minutes to two hours.

Q:  Why don't dolphins get cold during the winter or hot during the summer?
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).
For more information on blubber go to our anatomy page.

Q:  Which is the biggest dolphin?
The biggest member of the dolphin family is the orca (killer whale). The larger males grow up to 9.8m (32ft 2in) and weigh up to 10,000kg (22,046lbs). Their black, towering dorsal fins grow up to 2m (6ft 7in) and are unique among all whales and dolphins.   At birth, orcas are 2.1 to 2.6m (6ft 11in - 8ft 6in).

Q:  Which whale has the longest life span?
The life span of bowhead whales averages 100-200 years. 

Q:  Which is the fastest dolphin?
Dall’s porpoises are very speedy swimmers; they can reach up to 56kph (35mph). When they swim at high speeds, they create unique fan-shaped splashes of water, called "rooster tails" and this is used to identify Dall’s porpoise at sea. Orcas are also extremely fast swimmers and are probably the only dolphins to reach speeds similar to Dall’s porpoise.

Q:  Have any dolphins gone extinct?
The baiji or Yangtze River dolphin, once found in the Yangtze River in China, is sadly now believed to be extinct. The baiji holds the unfortunate award for being the first whale or dolphin to be driven to extinction by humans due to population pressures and industrialisation of China. In 2006 an international expedition searched for surviving baijis for six weeks. The boat survey covered the entire known range and devastatingly failed to record a single baiji; the scientists were forced to conclude that the baiji is probably extinct.

Q:  Which is the world's most endangered dolphin?
The vaquita, which in Spanish means ‘little cow’, is the smallest porpoise in the world, and also the most endangered. The vaquita lives only in Mexican coastal waters, in a small area of the northern Gulf of California. The species is in terrible trouble and facing imminent extinction; there are only about 30 individuals left. Accidental capture and death in fishing nets is the cause of their rapid decline in numbers.

The Maui dolphin is a tiny dolphin that is endemic to New Zealand. It is also the world’s smallest dolphin and rarest subspecies of dolphin, growing to a maximum length of 1.5m (5ft). The Maui dolphin is a subspecies of the Hector’s dolphin. The problem causing this rapid decline is entanglement in fishing nets as the dolphins are unable to detect the fine filaments of the net in the water and get caught and drown.