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| SCIENTIFIC
CLASSIFICATION |
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| COMMON
NAME: |
bottlenose
dolphin, Atlantic bottlenose dolphin, Pacific bottlenose
dolphin, bottle-nosed dolphin |
| KINGDOM: |
Animalia |
| PHYLUM: |
Chordata |
| CLASS: |
Mammalia |
| ORDER: |
Cetacea |
| SUBORDER: |
Odontoceti |
| FAMILY: |
Delphinidae |
| GENUS
SPECIES: |
Tursiops
truncatus |
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| DESCRIPTION: |
Bottlenose
dolphins are light to dark gray over their dorsal
surface, fading into a white or cream along their
ventral region. They have a streamlined fusiform
body shape. The source of their common name, bottlenose
dolphins exhibit a pronounced anterior rostrum
(often referred to as a beak), typically 7-8cm
(3 in.) in length. Said rostrum generally contains
76-98 conically-shaped, homogenous teeth - with
tooth counts varying among individuals. Their
dorsal fin is falcate.
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| It should be noted that two distinct ecotypes are recognized. The coastal ecotype typically exhibits smaller average body size with relatively larger flipper size. Comparatively, the offshore ecotype typically exhibit larger average body size and darker coloration - among other morphological distinctions. |
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| SIZE: |
Coastal ecotype = average 2.5-2.7 m (8.2-8.9 ft.)
Offshore ecotype = 3.7 m (12 ft.)
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| Atlantic bottlenose dolphins as a whole are typically smaller than Pacific bottlenose dolphins; however, bottlenose dolphins frequenting cooler, temperate waters in either ocean tend to exhibit sizes indicative of the relatively larger offshore ecotype. |
| Calves are approximately 106-132 cm (42-52 in.) at birth. |
| MALE |
Males
may be slightly larger than females |
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| WEIGHT: |
Coastal ecotype = average 190-260 kg (419-573
lbs.)
Offshore ecotype = average 454 kg (1,000 lbs.);
maximum 650 kg (1,433 lbs.)
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| Newborn calves weigh approximately 20 kg (44 lbs.) |
| MALE |
Physically
mature males tend to be more massive than physically
mature females |
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| DIET: |
Variety of fishes, squids, eels, and crustaceans
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| GESTATION: |
Approximately 12 months |
| ESTRAL
PERIOD |
Roughly
12 month anestrus followed by an approximate 12
month polyestrus consisting of at least 3 distinct
cycles, all of which are typically focused in the
late spring |
| NURSING
DURATION |
Up
to 18 months (wean) |
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| SEXUAL
MATURITY: |
Typically exhibited as a function of age-dependent
body size |
| MALE |
Sexual
maturity for males is attained once body length
reaches 2.4-2.6 m (8-8.5 ft.), generally between
9-13 years of age |
| FEMALE |
Sexual
maturity for females is attained once body length
reaches 2.3 m (7.5 ft.), generally between 5-12
years of age |
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| LIFE
SPAN: |
Approximately 20 years (average); Maximum lifespan
appears to be in 45-50 year range (with 1-2% of
population attaining maximum age)
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| MALE |
Maximum
lifespan for males appears to be in 40-45 year range |
| FEMALE |
Maximum
lifespan for females appears to be slightly greater
(i.e. 5-10 years) than that of males |
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| RANGE: |
Temperate and tropical marine waters worldwide;
In the Pacific, they are found from northern Japan
to Australia and from southern California to Chile;
In the Atlantic, they are found from Nova Scotia
to Patagonia and from Norway to the tip of South
Africa; In the Indian Ocean, they are found from
Australia to South Africa
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| HABITAT: |
Primarily temperate and tropical waters; coastal
ecotype typically inhabits nearshore waters including
harbors, bays, lagoons, gulfs, estuaries, with
occassional forays into large rivers; offshore
ecotype typically inhabits pelagic regions extending
to the continental shelf as well as select atolls
and ocean islands
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| POPULATION: |
GLOBAL |
Unknown |
| LOCAL |
Eastern tropical Pacific = 243,500 (approximate)
Northern Gulf of Mexico = 35,000-45,000 (approximate)
Western North Atlantic = 10,000-13,000 (approximate) |
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| STATUS: |
IUCN |
Data
Deficient (DD) |
| CITES |
Appendix II |
| USFWS |
Protected in U.S. waters by the Marine Mammal Protection
Act of 1972; not considered endangered or threatened |
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| 1. |
Dolphins
frequently ride the bow wake or the stern wake of
boats. They have been seen jumping as high as 4.9
m (16 ft.) out of the water and landing on their
backs or sides, in a behavior called a breach. |
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| 2. |
Both young and old dolphins chase one another, carry
objects around, toss seaweed to one another, and
use objects to invite each other to interact. Such
activity may be practice for catching food. |
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| 3. |
Bottlenose dolphins often cooperate when hunting
and catching fish. In open waters, a dolphin pod
sometimes encircles a large school of fish and herds
them into a tight ball for easy feeding. Then the
dolphins take turns charging through the school
to feed. Occasionally dolphins will herd fish to
shallow water where they are easy prey. |
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| 4. |
Bottlenose
dolphins generally do not need to dive very deeply
to catch food. Depending on habitat, most bottlenose
dolphins regularly dive to depths of 3-46 m (10-150
ft.). They are, however, capable of diving to
some depth. Under experimental conditions, a trained
dolphin dove 547 m (1,795 ft.).
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| 5. |
Bottlenose
dolphins live in fluid social groups called pods.
The size of a pod roughly varies from 2-15 individuals.
Several pods may join temporarily to form larger
groups called herds or aggregations. Up to several
hundred animals have been observed traveling in
a single herd.
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| 6. |
The
dolphin's sleek, fusiform body, together with its
flippers, flukes, and dorsal fin, adapt this animal
for ocean life. A dolphin's forelimbs are pectoral
flippers. As it swims, a dolphin uses its pectoral
flippers to steer and, with the help of the flukes,
to stop. |
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| 7. |
Bottlenose
dolphins routinely swim at speeds of about 5-11
kph (3-7 mph). |
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| 8. |
On
average, a dive may last 8-10 minutes. |
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| 9. |
Group
composition and structure often are based on age
and sex. Adult males tend to group together in pairs
or in threes. Females with calves associate with
one another. Individuals may leave one group and
join another. |
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| 10. |
Adults
eat about 4-5% of their body weight per day. Bottlenose
dolphins often cooperate when hunting and catching
fish. In open waters, a dolphin group sometimes
encircles a large school of fish and herds them
into a tight, dense mass for easy feeding. The dolphins
take turns charging through the school to feed while
the others keep the fish from scattering. Occasionally
dolphins herd fish to shallow water and trap them
against a shore or sandbar. |
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| 11. |
For
more information about bottlenose dolphins, explore
the bottlenose
dolphin info book. |
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Dolphins are important predators of fish, crustaceans,
and other marine fauna. They have been hunted
in many parts of the world for meat and other
by-products made from dolphin parts (such as fertilizer,
and machinery lubricants made from their jaw oil).
Possessing a larger brain than a human's, dolphins
show a high degree of certain types of intelligence,
making them popular subjects for research in fields
such as cetacean physiology, psychology, and sociology.
Their capacity for learning has also made them
ideal trained performers in oceanarium and zoological
shows.
Under
the Marine Mammal Act of 1972, the taking of dolphins
requires a special permit. Bottlenose dolphin
populations were drastically reduced around the
turn of the last century due to commercial fishing
operations. The biggest problem still facing dolphins
today is the indirect negative affect of commercial
tuna fishing, which uses gigantic nets in which
dolphins become easily entangled and killed.
Not only is it illegal, but it also may be dangerous
to approach a wild dolphin. Marine parks like
SeaWorld and Discovery Cove provide a safe environment
for humans to interact with dolphins.
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|
|
| Byrum,
Jody and Nuzzolo, Deborah. Bottlenose Dolphins.
Third Edition. SeaWorld Education Department,
1996. |
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| Jefferson,
T.J. Leatherwood, S. and M.A. Webber. FAO Species
identification Guide. Marine Mammals of the World.
Rome. FAO, 1993. |
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|
Leatherwood,
Stephen, and Reeves, Randall R. The Sierra
Club Handbook of Whales and Dolphins. San
Francisco: Sierra Club Books, 1983.
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| Nowak,
Ronald M. (ed.). Walkers Mammals of the World.
Vol. II. Baltimore: Johns Hopkins University
Press, 1991. |
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| Nuzzulo,
Debrorah. Dolphin Discovery: Bottlenose Dolphin
Training and Interaction. SeaWorld Education
Department Publication, SeaWorld, Inc., 2003. |
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| Parker,
S. (ed.). Grizmeks Encyclopedia of Mammals. Vol.
IV. New York: McGraw-Hill Publishing Co., 1990. |
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| Reeves,
R. R., Stewart, B.S., Clapman, P.J., and J.A. Powell
(Peter Folkens illustrator). National Audubon
Society: Guide to Marine Mammals of the World.
New York: Random House, 2002. |
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| http://animaldiversity.ummz.umich.edu |
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