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| SCIENTIFIC
CLASSIFICATION |
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| COMMON
NAME: |
Aldabra
tortoise, giant tortoise |
| KINGDOM: |
Animalia |
| PHYLUM: |
Chordata |
| CLASS: |
Reptilia |
| ORDER: |
Testudines |
| FAMILY: |
Testudinidae |
| GENUS
SPECIES: |
Geochelone
(land turtle) gigantea (giant) |
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| DESCRIPTION: |
They are dark gray to black in color with a highly
domed thick carapace, a very long neck to aid in
food gathering, and short, thick legs. |
| MALE |
Males have longer, thicker tails than females. |
| FEMALE |
text |
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| SIZE: |
text |
| MALE |
Mature males have an average carapace (shell) length
of 122 cm (4 ft.) |
| FEMALE |
Adult
female carapace length averages 91 cm (3 ft.). |
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| WEIGHT: |
text |
| MALE |
Adult males up to 250 kg (550 lb.) or more. |
| FEMALE |
Mature females average 159 kg (350 lb.) |
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| DIET: |
Though
it feeds primarily on vegetation, the Aldabra tortoise
is flexible and opportunistic in its diet. In order
to obtain enough nourishment for survival, the tortoise
may supplement its diet with small invertebrates
and even carrion (including dead tortoises). |
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| INCUBATION: |
Incubation is temperature dependant: in warm temperatures,
eggs hatch in about 110 days; in cool temperatures,
eggs take 250 days to hatch. |
| CLUTCH
SIZE |
The
females lay between 4 and 14 eggs, of which less
than one half are fertile.
9-25
eggs
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| BREEDING
PERIOD |
In
healthy, uncrowded populations, a second clutch
(laying) within the same breeding season is likely. |
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| SEXUAL
MATURITY: |
Sexual maturity is determined by size rather than
by age; most species begin to reproduce when they
reach approximately half their full-grown size,
usually around 25 years of age. |
| MALE |
text |
| FEMALE |
text |
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| LIFE
SPAN: |
Unknown, probably easily lives over 100 years |
| MALE |
text |
| FEMALE |
text |
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| RANGE: |
The
entire wild population of Aldabras is restricted
to the Aldabra Atoll (a small group of coral islands
in the island nation of Seychelles, north of Madagascar). |
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| HABITAT: |
There are many different habitats on the islands
where tortoises can be found, including scrub, mangrove
swamp, and coastal dune. The largest concentrations
of tortoises are found on the grasslands called
platins. |
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| POPULATION: |
GLOBAL |
text |
| LOCAL |
text |
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| STATUS: |
IUCN |
Listed as vulnerable |
| CITES |
Appendix II |
| USFWS |
Not listed |
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| 1. |
The
Aldabra tortoise is the largest animal on the atoll.
The tortoises fill a niche very similar to the one
occupied by elephants in Africa and Asia. As with
elephants, they are the main consumers of vegetation
and noticeably alter the habitat during their search
for food. Tortoises have been known to knock over
small trees and shrubs to obtain nutritious leaves.
This makes pathways and clearings within the forestlands
for other animals. Seeds pass through the tortoise's
digestive tract and eventually become food for many
other species. |
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| 2. |
The
Aldabra tortoise is one of the longest-lived animals
on earth, if not the longest. No one knows exactly
how long these animals are capable of living, but
they are believed to easily surpass 100 years. So
far, the tortoises studied have outlived the scientists
studying them, and proper records have not been
maintained. |
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| 3. |
text |
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| 4. |
text |
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| 5. |
text |
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| 6. |
text |
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The
Aldabra tortoise is the only remaining species
out of 18 former species of tortoise that once
flourished on the islands of the Indian Ocean.
The others went extinct because of hunting by
sailors and the predation of eggs and hatchlings
by introduced species such as rats, cats, and
pigs.
This
was one of the first species to be protected in
order to ensure its survival for the future. Charles
Darwin and other notable conservationists of the
day along with the governor of Mauritius set aside
a captive breeding population on Mauritius as
well as protecting the Aldabra Atoll.
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Bourn,
D. "Reproductive Study of Giant Tortoises
on Aldabra". J. Zool., London, Vol.
182, 1977, pp. 27-38.
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Collins,
David E. "Captive Breeding and Management
of the Aldabra Tortoise." Presentation to
8th International Herpetological Symposium, Jacksonville
Zoo, Jacksonville, FL, 1984.
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Gibson,
C.W.D. and Hamilton, J. "Population Processes
in a Large Herbivorous Reptile: The Giant Tortoises
of Aldabra Atoll." Occologia (Berlin),
Spring-Summer, 1984, pp. 230-240.
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Grubb,
P. "The Growth, Ecology, and Population Structure
of the Giant Tortoises on Aldabra." Phil.
Trans. Roy. Soc. Lond. B, Vol. 260, 1971,
pp. 327-372.
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| Peters, U.W. and E.P.
Finne. "First Breeding of the Aldabra Tortoise
at Sydney Zoo." |
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Pritchard,
Peter C.H. Encyclopedia of Turtles. Neptune,
New Jersey: T.F.H. Publications, Inc. Ltd., 1979.
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Spratt,
David M.J. "Operation Curiesue: A Conservation
Programme for the Aldabra Giant Tortoise in the
Republic of Seychelles." Int. Zoo Yb.,
Vol. 28, 1989, pp. 66-69.
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Stearns,
Brett C. "Captive Husbandry and Propagation
of the Aldabra Giant Tortoise." Int. Zoo
Yb., Vol. 27, 1988, pp. 98-103.
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Stoddart,
D. R. "Retrospect and Prospect of Aldabra
Research." Nature, March 15, 1969,
pp. 1004-1006.
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Stoddart,
D. R. "The Aldabra Affair." Biological
Conservation, 1974, pp. 63-69.
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Swingland,
Ian R. "Securing the Tortoises Future."
Country Life, August 30, 1984, pp. 568-569.
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Swingland,
Ian R. "Aldabran Giant Tortoise." The
Conservation Biology of Tortoises, Occasional
Papers of the IUCN Species Survival Commission
(SSC), No. 5, 1989.
Swingland, Ian R. and Klemens, Micheal W. (ed).
The Conservation Biology of Tortoises. Occasional
Papers of the IUCN. Species Survival Commission
(SSC) No. 5 1985.
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