Questions and Answers about Dolphins

The species living at Ocean World is bottlenose dolphins



What is a dolphin's life span?

Bottlenose dolphin survival rates for the Sarasota population (the only one studied in enough detail) is 0.961.   This means that at least in the Sarasota Bay (and also in captivity) the life expectancy (the average age they can be expected to reach) is about 25 years.   The maximum age (which only a few will reach) is more than 40 years.   Survival rates in other populations may be different (the Indian River population in Eastern Florida has an estimated survival rate of about 0.92 which means a life expectancy of about 12 years).

 

Is the dolphin life span shorter when in captivity?

The answer to that one is "No" for bottlenose dolphins.

This issue was the subject of a paper by R.J Small and D.P. DeMaster:
"Survival of five species of captive marine mammals", published in Marine Mammal Science, vol. 11(2): 209-226 (April 1995).
This study showed no significant differences between the survival rates of bottlenose dolphins in captivity and in the wild (the Sarasota Bay population).




How long can dolphins go without being in water?

 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.
(This is why elephants and hippopotami often spend time in water.)
Also, whales are well insulated (blubber), which is good if they're in water, but not if they're beached. 
It's like having a winter coat in 70 degree weather- you'd overheat very quickly. 

Also, 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.




Do dolphins have a sense of smell?

 The olfactory lobes in the cetacean brain are quite atrophied and non-existent in some species.
In most cetaceans, the olfactory nerves and chemoreceptors have disappeared or exist in a rudimentary form only.

Bottom line: Cetaceans can taste, but have no sense of smell.


What are the sounds a dolphin can produce?

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 too).

Do dolphins have a language?

The answer for now should be "it is possible that they do...".  Do we have a chance to comprehend it some day?  Will we be able to communicate in return?   These are not easy questions to answer and will not be answered very soon.   Studies and research on complex sounds exchanges between dolphins are still under way.  Sounds do not alone account for communication between dolphins.    Attitudes do also.    Body talk (mammals we said) is evident in many ways, as when a perturbed mother will hold a misbehaving child on the bottom.   The message is clearly "don't mess with me and get back in line".    Dolphins will also slap their tail flukes on the surface as a kind of "hey stop that".    Communications does seem to take place on a much subtler level with posture and body contact.



How much do dolphins eat per day?

 Bottlenose dolphins (Tursiops Truncatus) consume approximately 8-15 kg (15-33 lb.) per day
and Orcas (Orcinus orca - albeit captives ones) approximately 45 kg (100 lb.) per day.



How do dolphins sleep?

 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.

 

Can dolphins live in fresh water and salt water?

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. They are Ganges River Dolphin, Indus River Dolphin,Amazon River Dolphin, Franciscana, Chinese River Dolphin


What types of dolphins are there?

There are 32 Dolphin Species. The bottlenose dolphin is the species found at Ocean World
Species Common Name Characteristics Location Food
Tursiops truncatus Bottlenose dolphin 230 kg, 3.9 meters All seas Fishes, cephalopods
Delphinus delphis Common Dolphin 75 to 85 kg, 1.70 to 2.40 meters All seas except polar seas Fishes, cephalopods, anchovy
Cephalorhynchus hectori Hector's Dolphin 1.2 to 1.40 meters, 40 to 50 kg Coasts of New Zealand Small fish, cephalopods
Cephalorhynchus commersonii Commerson's Dolphin max. 1.7 meters, 40 to 60 kg Coasts of Argentina, Chili,
Falkland, Kerguelen
Kril, crabs, small fish, cephalopods
Cephalorhynchus eutropia Black Dolphin 1.6 meters, 50 kg Coasts of Chili (unknown)
Cephalorhynchus heavisidii Haeviside's Dolphin (no data) Coasts of South Africa Fishes, cephalopods
Lissodelphis peronii Southern Right Whale Dolphin 2.3 to 3 meters, no dorsal fin Southern hemisphere Mainly cephalopods, fishes
Lissodelphis borealis Northern Right Dolphin 2.3 to 3 meters, no dorsal fin Northern hemisphere Cephalopods, fishes
Stenella attenuata Spotted Dolphin 2.2 to 2.5 meters Tropical & subtropical seas Fishes, squids
Stenella plagiodon Atlantic Spotted Dolphin 2.2 to 2.5 meters Tropical Atlantic only Fishes, squids
Stenella caeruleoalba Striped Dolphin 2.7 meters, black stripe from eye to tail Tropical seas Small fish, shrimps
Stenella longirostris Spinner Dolphin 1.8 to 2.1 meters Atlantic, Indian Ocean, Pacific Long and narrow fishes
Stenella clymene Clymene Dolphin 1.8 to 2.1 meters Tropical & subtropical Atlantic Fishes, cephalopods
Lagenorhyncus albirostris White-Beaked Dolphin max. 3.1 meters Cold seas, North Atlantic Fishes, cephalopods
Lagenorhyncus acutus Atlantic White-Sided Dolphin max. 2.7 meters Cold seas, North Atlantic Fishes, cephalopods, shrimps
Lagenorhyncus obliquidens Pacific White-Sided Dolphin 2.3 meters, 150 kg Cold and mild seas, North Pacific Fishes, cephalopods
Lagenorhyncus obscurus Dusky Dolphin 1.5 to 1.7 meters Cold coastal waters of southern hemisphere Anchovy, cephalopods
Lagenorhyncus cruciger Hourglass Dolphin 1.5 to 1.8 meters Cold waters, Antarctic (unknown)
Lagenorhyncus australis Peale's Dolphin 2.3 meters Cold coastal waters, South America, Falkland Cephalopods, fishes
Lagenodelphis hosei Fraser's Dolphin 2.3 to 2.7 meters, 160 to 210 kg Tropical waters Cephalopods, fishes
Grampus griseus Risso's Dolphin 3.6 to 4 meters Tropical and warm waters cephalopods, some fishes
Steno bredanensis Rough-Toothed Dolphin 2.3 to 2.8 meters Tropical and warm waters Fishes, octopus, calamars
Orcaella brevirostris Irrawaddy Dolphin 2 to 2.5 meters Tropical Indian Pacific Fishes
Peponocephala electra Melon-Headed Whale 2.5 to 2.7 meters Coastal & high seas, tropical & subtropical cephalopods, small fish
Feresa attenuata Pygmy Killer Whale 2.2 to 2.7 meters Tropical & subtropical waters cephalopods, fishes
Sotalia fluviatilis Tucuxi 1.4 to 1.9 meters Coast and rivers South America
from Brazil to Panama
Sousa chinensis Indo-Pacific
Humpbacked Dolphin
2 to 2.8 meters, max. 285 kg Indonesia Fishes
Sousa teuszii Atlantic
Humpbacked Dolphin
same as Sousa chinensis West Africa Fishes
Globicephala melaena Long-Finned Pilot Whale 5.5 to 8.5 meters, 3 to 3.5 tons All oceans, except Pacific Cephalopods, morua
Globicephala macrorhynchus Short-Finned Pilot Whale 4 to 4.5 meters, 2.5 tons Warm & tropical waters Cephalopods
Pseudorca crassidens False Killer Whale 5 to 6.1 meters, 1.4 to 2 tons Warm & tropical waters Cephalopods, big fish
Orchinus orca Killer Whale 6.5 to 9.5 Meters
4 to 8 Tons
black & white
All coasts and seas Infant whales, small dolphins, seals, turtles, fishes


Where are dolphins located?

Dolphins have colonized all oceans and seas of the planet, from polar to tropical regions, true mammals they must get oxygen from air and not from water such as fish, their infants are born underwater and must be brought up to the surface immediately to survive.  Another dolphin is often present to help the mother when birth is taking place.    Presence or non presence of dolphins is a good indication of the state of the seas in many parts of the world.   Very common in some places twenty years ago it has disappeared since.   In other regions it is coming back because of man efforts to de-pollute.

Climate or change in currents or sea temperature can also make dolphins disappear or come back after many years, the most remarkable case of this is the Monterey Bay in California where the Risso Dolphin reappeared in 1970 after a non presence of 70 years.

Are dolphins naturally friendly?

Dolphins seems to enjoy playing games with humans; they invent them if you don't.

We all heard of the famous stories about the dolphin rescues where a human is pushed to the safety of the shore by dolphins.
Bottlenose dolphins seems to enjoy pushing items.

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.
One solitary dolphin, interact with humans more than with any pod.
Jean Louise, a solo dolphin who lived in Brittany for many years, seemed to enjoy swimming with people but did not allow physical contact.
If dolphins have spent time in captivity, they can become very use to people touching them, riding along with them, etc.
But they also can become mildly aggressive; nipping, pushing, etc.

These are strong creatures with territorial interests.
It is also know of one dolphin in Italy that they didn't know what to do with because he was so aggressive with humans and other dolphins.


What is the dolphin greatest predator?


Man is the dolphin greatest predator, more than 100,000 dolphins die each year because of man, either in nets or for gastronomy (being eaten).   In the Pacific Tunas and Dolphins follow the same routes, for years they were both captured in the nets aimed at the Tunas, the Dolphins were either drowned or slaughtered.
From 200,000 to 500,000 dolphins were killed this way between 1960 and 1972.

Now under pressure of common citizens, new legislation, actions of nature and wild life organizations, fishing industries in many countries have adopted new nets so that dolphins can escape.   Tuna is now guaranteed to be "Dolphin Safe" in many regions of the globe (not all).
Despite ecologist actions Dolphins are still being served as meals in many parts of Japan, and hundreds are massively slaughtered each year in the Faeroe Islands.
Pollution of rivers, seas, and oceans by man activities is also a great danger for many species of dolphins, at the end of the food chain this mammal will concentrate all the poisons and chemicals man does release in its habitat.

The second predator of Dolphin after man is the Shark, the worst areas for these encounters are South Africa and Australia.

Finally the third greatest predator of Dolphins are .... Dolphins.   Orcas have the habit to eat fish, seals, infant whales and small dolphins.

-------------------------------------------------------

$2,500 Reward For Turning In A Dolphin Poacher

If you witness the illegal capture, killing, or harassment of any marine mammal, such as bottlenose dolphins, whales, and seals, you may be able to receive a reward of up to $2,500 from the federal government.  To get a reward, the information you provide has to lead to a conviction for a violation of the Marine Mammal Protection Act.  You can receive up to one-half of the fine that the government collects based on your complaint.

If you witness a fisherman shooting at dolphins to scare them away from his fishing lines...

If a business imports fur seal skin wallets and is trying to get other businesses to buy them for resale...

If a fishing boat allows much more than the legal limit of dolphins to get caught in their nets...

Contact:

Office of Enforcement
National Marine Fisheries Service
National Oceanic and Atmospheric Administration
U.S. Department of Commerce
1335 East-West Highway
Silver Spring, MD 20910
(301) 443-8910


Are dolphins endangered?

 The bottlenose dolphin is not endangered.

The following dolphins species are listed as endangered
(according to the IUCN Red Data Book,1991):

Indus river dolphin
(Platanista minor)

Baiji or Yangtze river dolphin
(Lipotes vexillifer)

 

The following species are listed as vulnerable:

Ganges river dolphin
(Platanista gangetica)

Amazon river dolphin
(Inia geoffrensis)


Note:
The status of many species is simply insufficiently known to determine if they are in any danger or not.






When did dolphins appear on Earth, what are its ancestors?

 All dolphins and whales belong to the scientific order of Cetacean. 
All cetacean are marine mammals that have adapted marvelously to water and lost the faculty to come back on land again.  Forever.

This order is divided into three suborders.
The toothed whales or Odontoceti which does include the killer whales, the beluga whales, the dolphins, and the porpoises.
The Mysticeti which does include the blue whales and the gray whales.
Finally the Archaeoceti which represent the extinct specie. 

First cetacean are believed to have appeared 50 millions years ago and colonized all seas when immersed lands were still nothing but a dense jungle. 
The oldest fossil named "Pakicetus" was found in the eighties near the Himalayan mountains on the Pakistani border.
Studies of this fossil have showed that it had still four limbs.
So it is clear that some mammals already living on land did return to the sea.
Why?   It is not known.

This group was extinct about 15 millions years ago when the "squalodonte" or first cetacean (toothed whales of which the dolphin descent) appeared.  

Fossils found in Italy and Germany along the Rhine river have identified the typical "squalodonte".
Legs are replaced by fins, one nostril has migrated on top of the head and has become a blow hole, the body is long and narrow, long range of teeth have appeared.   It is already closer to the actual Orca than the older specie.  

Modern forms of odontocetes appeared four to five million years ago.






What's the purpose of the Dolphin sonar?

 

The proper term is echolocation.  As stated in previous answer Dolphins can emit sounds from 1.5 to 11.0 kHz.  Most echolocation takes place in the range of 2.0-4.0 kHz for Tursiops truncatus, as does most other vocalizations, whistles can go as high as 15 kHz. Sounds are believed to be emitted by the "nasal sac", an area just behind the melon (the rounded region of a dolphin's forehead). The melon itself might be used as a acoustic lens to focus these sounds. Low frequencies are emitted to locate far away objects as they travel far under water due to their long wave length. High frequencies locate objects at close range with high precision but don't travel far due to their short wave length. Dolphins can determine size, direction, speed, distance, and some of the internal structure of any objects under water. A female dolphin can detect that a swimming human female is pregnant (and will often in reaction tend to protect her). As the produced wave of sounds bounce off distant or close objects, the Dolphin receives in echo an acoustic "image" that is send to the brain in the form of nerve impulses for interpretation and action. Dolphin can detect a band of fish more than a hundred meters away.

Following are a few printed and electronic sources of information on dolphin sonar,
Books:

The Sonar of Dolphins.
    Au, W. W.
    New York: Springer- Verlag,1993.

Animal Sonar Systems.
    Busnel, Rene-Guy, and James F. Fish, eds.
    New York: Plenum Press, 1980.

Porpoises and Sonar.
    Kellogg, Winthrop N.
    Chicago, Illinois: The University of Chicago Press, 1961.

The Bottlenose Dolphin.
    Leatherwood, Stephen, and Randall R. Reeves, eds.
    San Diego,     California/London: Academic Press, 1990.
    (This is the definitive work on bottlenose dolphins.)

Echolocation in Whales and Dolphins.
    Purves, P. E., and G. E. Pilleri.
    New York: Academic Press, 1983.


WEB SITES:

Sea World        
    http://www.seaworld.org/

Wesley R. Elsberry
    http://www.rtis.com/nat/user/elsberry/

Chris Sturtivant's page
    http://sonar-fs.lboro.ac.uk/  

Coastal Ecosystems Research Foundation
    http://cerf.bc.ca/index.asp







Where can I swim with Dolphins?

 

Note:
Under the Marine Mammal Protection Act of 1972 (revised 1984) it is illegal
to actively interacting with wild dolphins within United States boundaries,
This is not true in other parts of the world.

The Agriculture Department issued a proposals on Jan. 23, 1995
which details rules to protect dolphins at popular tourist attractions
that give people an opportunity to swim with the mammals.

 

There are currently six legally registered dolphin-swim programs in the United States,
the USDA said, but animal welfare groups said the unofficial number is much higher.

The USDA suggests items, such as the rule that limits the people-to-dolphin ratio at 3-to-1
and another that states dolphins can only spend two hours interacting with people per day,
with a 10-hour rest period every 24 hours.  
They also have limits on the size of the interaction area.

However you should never forget YOU are the visitor of the dolphin habitat, so please respect them.

 

US Locations where you can swim with dolphins.


Florida keys (Swim with dolphins in a tank)

    Sea World
    Orlando, Florida

    Dolphin Research Center
    MM 59 1/5 Highway US 1
    Grassy Key, Florida 33050
    (305) 289-0002

    Dolphins Plus
    31 Corrine Place
    Key Largo, Florida 33037
    (305) 451-1993

    Theater of the Sea
    MM 84 1/5 Highway US 1
    Islamorada, Florida 33036
    (305) 664-2431



Florida keys (Swim with dolphins in the wild)

    Capt. Ron Canning
    Dolphin Watch
    Key West, FL
    (305) 294 6306

    Capt. Vicki Impallomeni
    1737 Laird St.
    Key West, FL 33040
    (305) 294 9731


Hawaii

    Hilton Waikoloa on the Big Island






 

What are some Dolphin friendly movies?

Title Date
Atlantis 1991
Day of the Dolphin, The 1973
Free Willy 1993
Free Willy 2 1995
Johnny Mnemonic 1995
Orca 1977
Star Trek IV 1986
Whale of a Tale 1976

 

What celebrities are involved in dolphin causes?

Bridget Fonda starred in Dolphins in Danger (TBS, Sept. 1, 1996),
a documentary about the environmental hazards faced by the wild dolphins off the Bahamas.

Pierce Brosnan is an active supporter of Planet Ark, an environmental organization based in Australia.

Brosnan is particularly active in Planet Ark's efforts to protect dolphins.

 

 


Special thanks to:
Sea World • Planet Ark • Andrew Comello • George Elston • Trisha Lamb Feuerstein • Bruce Lane • Bill Levinson • Jaap van der Toorn


 

courtesy

RainbowDolphin.com