Where are dolphins located? Can dolphins live in fresh water and salt water?
How many different kinds of dolphins are there? Are dolphins naturally friendly?
What is the dolphins greatest predator? What is the dolphins life span?
Are dolphins endangered? How do dolphins sleep?
How fast can a dolphin swim? What is the distance a dolphin can travel?
How deep can a dolphin dive? Do dolphins have a sense of smell?
How much do dolphins eat per day? What do dolphins eat?
How long can dolphins go without being in water? What is the difference between a dolphin and a porpoise?
What are the sounds a dolphin can produce? Why do dolphins make so many sounds?
Why do spinner dolphins spin? How large are spinner dolphins compared to other dolphins?
How can you tell the difference between a male and a female dolphin? Do dolphins hibernate?
Do dolphins mimic people? Do dolphins have any form of camouflage?
How often do dolphins give birth? How long do dolphins stay pregnant?
How intelligent are dolphins? How high can a dolphin jump?
What is a Male/Female/Baby dolphin called? How do dolphins drink?
Do dolphins have hair?
Dolphins are air breathing mammals that inhabit all the oceans of the world.  Sleek and aerodynamically formed, they are tight skinned and feel rubbery to the touch.  There are over thirty dolphin species in all, and they are differentiated from each other not only by size, but also by shape and markings.

Dolphins are highly intelligent creatures, and considerable evidence exists attesting to their intelligence.  They live is close knit social groups called "pods", and have a complex communication system, including their own names or "signature whistles".
 

Spinner Dolphin


Q.  Where are dolphins located?
A.  Dolphins have colonized all oceans and seas of the planet, from polar to tropical regions.   Presence or non presence of dolphins is a good indication of the state of the seas in many parts of the world.


Q.  Can dolphins live in fresh water and salt water?
A.  Yes, 5 specific species live in fresh water, they are usually named after the river they swim in such as the Amazon, the Yangzi Jiang, or the Ganges.


Q.  How many different kinds of dolphins are there?
A.  There are 32 species of oceanic dolphins (Delphinidae family) and six porpoise species (Phocoenidae family).  There are five river dolphin species found in five different rivers.


Q.  Are dolphins naturally friendly?
A.  Dolphin species vary in their degree of curiosity and interaction with humans.  Individual dolphins vary to the same degree.  Some species are very shy, others will approach humans with great curiosity.  If dolphins have spent time in captivity, they can become very used to people touching them, riding along side of them, etc., but they also can become mildly aggressive; nipping, pushing, etc.
We all heard of the famous stories about dolphin rescues where a human is pushed to the safety of the shore by dolphins.  Bottle-nose dolphins seem to enjoy pushing items.  (Of course we wouldn't hear about the people being pushed out to sea!)


Q.  What is the dolphins greatest predator?
A.  MAN!  Man is the dolphins greatest predator, more then 100,000 dolphins die each year because of man, either in nets or for gastronomy.

The second predator is the shark, the worst areas for these "too close" encounters are South Africa and Australia.

Finally the third is the.........dolphins.  Orcas have the habit or eating fish, seals, infant whales and small dolphins.


Q.  What is the dolphins life span?
A.  The average life expectancy for the bottle-nose dolphins is about 25 years.  the maximum age (which only a few will reach) is more than 40 years.


Q.  Are dolphin endangered?
A.  The river dolphins are the only dolphins that are endangered or vulnerable right now.


Q.  How do dolphins sleep?
A.  Dolphins sleep only with one half of their brain at a time.  Remember dolphins are conscious breathers.  Should they sleep and go unconscious as we do they would simply suffocate or drown.  Sleeping dolphins can be seen as resting, floating at the surface, with one eye open.  After a time, they will close the one eye and open the other one.  They alternate like this throughout their entire nap.


Q.  How fast can a dolphin swim?
A.  Dolphins can swim up to 40 km/hr, due to special structures in the skin that reduce turbulence.  They spend the least amount of energy when swimming at speeds of about 8 km/hr.


Q.  What is the distance a dolphin can travel?
A.  The distance a dolphin travels depends very much on its food supply.  The optimum swimming speed is about 8 km/hr.  Dolphins sleep about 8 hours a day which would leave 16 hours for travel.  This would mean they can travel up to 128 km per day.  How much they actually do travel is unknown.


Q.  How deep can a dolphin dive?
A.  The dolphin is capable of diving for up to 20 minutes at 300 meters, this is to be considered as maxima for a bottle-nose dolphin although in some experiments they have dived to about 500 meters.  Usually, bottle-nose dolphins will not dive very deep.


Q.  Do dolphins have a sense of smell?
A.  Dolphins can taste, but have no sense of smell.


Q.  How much do dolphins eat per day?
A.  Bottle-nose dolphins consume approximately 8-15 kgs (15-33 lbs.) per day and Orcas approximately 45 kgs (100 lbs.) per day.


Q.  What do dolphins eat?
A.  Dolphins and porpoises are carnivores - most eat fish and/or squid.  Different habitats mean different diets; each type of dolphin and porpoise specializes in catching prey that lives in their specific ecosystem.


Q.  How long can dolphins go without being in water?
A.  Dolphins and whales out of water have two problems: heat and their own weight.  Large animals have low surface to volume ratios, so it is hard for them to cool themselves.  Also, whales are well insulated (blubber), which is good if they're in the water, but not if they're beached.  It's like having a winter coat on in 70 degree weather, you'd overheat very quickly.  A whale's body isn't designed to support its own weight, it relies on water for support.  The larger whales will die from their own weight if they're beached long enough.


Q.  What is the difference between a dolphin and a porpoise?
A.  There are slight physical differences between dolphins and porpoises:
* Porpoise teeth are shaped like spades and each tooth has a long, sharp upper edge.
* Dolphin teeth are shaped like cones and are pointed.
* Porpoises tend to be smaller than dolphins and usually do not have pronounced beaks.
* Whales, dolphins and porpoises are in the same scientific group Cetacea.
* "Whale" is a common name used to describe a large cetacea.  It relates to relative size, much like the distinction between "boat" and "ship".
* Killer whales, melon headed whales, pilot whales, and false killer whales are all part of the dolphin family, but are called whales because of their size.


Q.  What are the sounds a dolphin can produce?
A.  All dolphins and whales can produce complex sounds, both for communication among them and for navigation under water. The common dolphin can hear sounds upwards of 150 KHz but generally produce sounds ranging from 1.5 to 11.0 KHZ.  Patterns of sounds can be observed, mostly clicking, moans, whistles, trills, and squeaks.  Males can whistle to get the attention of females or to warn the group of imminent danger (so does man, we are all mammals).


Q.  Why do dolphins make so many sounds?
A.  Whistle like sounds help dolphins keep in contact and communicate with each other as they travel and feed.  Dolphins "echolocate" to find their food or to scan their surroundings.  They direct "clicks" into the water and the  clicks rebound off solid objects (fish, logs, boats) and echo back to the dolphins.  Dolphins listen for the strength of the rebounding clicks to identify what the object is and its distance from them.  All of these clicks and whistles are created in the dolphin's nasal passages just below the blowhole.


Q.  Why do spinner dolphins spin?
A. There is probably more than one reason for why spinner dolphins spin. The one that has been documented the most has to do with remoras, a group of fishes that has one of the fins on their back modified into a suction cup. The suction cup allows the remora to attach to a shark, marlin, whale or dolphin to get a free ride. The problem for the marine mammals is the way the fish makes sure that the suction cup does not slide around on its host,  by sinking thousands of little needle-like bones into the skin of the host. This does not cause  much of a problem to a shark or a marlin, but to a  dolphin, with sensitive skin, it may be a major irritant.

If looking at photographs of spinning dolphins, one  will find a remora attached to the spinner in about  70% of the photos. This is especially significant,  when you consider that you will only be able to see  50% of the spinner dolphin's body in the photo.


Q. How large are spinner dolphins compared to other dolphins?
A. Spinner dolphins are one of the smallest species of dolphins. They are only 1.5-2 meters long, an they weigh around 75-95 kilograms. For a  comparison, bottlenose dolphins (Flipper was a  bottlenose dolphin) can reach lengths of almost 4  meters and weigh up to 600 kilograms!


Q. How can you tell the difference between a male and a female dolphin?
A. To find this out you have to look underneath the dolphin at it's belly.  If you see a long slit with 2 smaller slits, that's a female:
                   _
 Head  _______  tail
                  _

The smaller slits are the openings for the mammary glands.

For a male, it's more like this:

 Head  ____ _  tail

(No slits to the sides.)


Q. Do dolphins hibernate?
A. No.  In fact, they never fully sleep.  When people breath, they do so involuntarily;  as they sleep, they continue to breath.  Dolphins, on the other hand, must swim to the surface, and then breath voluntarily.  As a result, they don't sleep like we do.  It is believed that only half of their brains sleep at a time.  While one half of their brains is asleep, the other half is monitoring their swimming to the surface to take a breath.


Q. Do dolphins mimic people?
A. In general, no.  Some dolphins in captivity have learned to mimic people, where they get 'rewards' for doing so.  But those in the wild do not  - there is no reason for them to do so.


Q. Do dolphins have any form of camouflage?
A.  Yes, seen from above they blend in with the water, and if you're a killer whale looking up, their bellies blend in with the sky.  It's  called counter shading.


Q. How often do dolphins give birth?
A. Dolphins like bottlenose dolphins give birth about once every 2-4 years. If the calf is healthy, it will nurse for 1-2 years...weaning takes place then but it takes awhile.


Q. How long do dolphins stay pregnant?
A. Dolphins are pregnant for a whole year!!


Q. How intelligent are dolphins?
A. The short answer to this is that we do not know. There is no reliable method to measure intelligence in humans across cultures, so it is not surprising that comparing humans, dolphins, apes, dogs, etc. is impossible. There are some indications of their potential: they are fast learners and can generalize (which is also true of pigs, BTW). Also they can learn to understand complicated language-like commands (which is also true of the great apes).


Q. How high can a dolphin jump?
A. Dolphins can jump as high as 5 m (16 ft.) from the surface of the water and landing on their backs or sides.


Q. What is a Male/Female/Baby dolphin called?
A.  A male dolphin is a bull, a female dolphin is a cow and a baby dolphin in a calf.


Q. What do dolphins drink?
A.  Dolphins’ main prey (fish and squid), contains large amounts of water and so dolphins obtain water from their food. Fish, such as herring and mackerel can be made up of as much as 80% moisture, whilst moisture levels in squid are even higher. In addition, dolphins don't actually need to take in very much fluid because, unlike us, their skin is impermeable and they don't lose water by sweating.


Q. Do dolphins have hair?
A.  Dolphins are born with a small amount of hair on their beak (nose), but in when they become adults, only the hair follicles remain.
 

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This page was created by Kelly
Last updated 04/06/06