 |
|
|
| |
| SCIENTIFIC
CLASSIFICATION |
|
| COMMON
NAME: |
Commerson's
Dolphin |
| KINGDOM: |
Animalia |
| PHYLUM: |
Chordata |
| CLASS: |
Mammalia |
| ORDER: |
Cetacea |
| FAMILY: |
Delphinidae |
| GENUS
SPECIES: |
Cephalorhynchus
commersonii |
|
|
|
| |
|
|
| DESCRIPTION: |
Commerson's
dolphins are a small and very distinctive species
with mostly black on the head, fin and flipper regions
and mostly white in the other areas of the body.
Young Commerson's are usually brown or black and
gray for the first four to five months. The dorsal
fin is small and rounded at the tip and the beak
is small or unnoticeable. |
| FEMALE |
In
this species, females are typically larger than
males. |
|
| SIZE: |
These
are one of the smallest dolphins reaching lengths
of up to 1.2-1.7 m (3.9-5.6 ft). Newborn calves
are approximately 55-65 cm (21.7-25.6 in) in length. |
|
| WEIGHT: |
Commerson's
dolphins can reach weights of up to 35-60 kg (77-132
lbs). At birth, calves average 4.5-5.5 kg (10-12
lbs). |
|
| DIET: |
Feeds
on krill, cuttlefish, squid, shrimp and small fishes |
|
| GESTATION: |
Gestation
lasts a maximum of approximately 12 months. |
| ESTRAL
PERIOD |
Between
late winter and early spring |
| NURSING
DURATION |
Unknown;
at least 4 or more months |
|
| SEXUAL
MATURITY: |
5-8 years |
|
|
|
| RANGE: |
From
the tip of South America (Peninsula Valdes to Tierra
del Fuego), through the Strait of Magellan, around
the Falkland Islands and the Kerguelen Islands.
There are two populations of Commerson's dolphins;
the population off the coast of southern South America
and another population found around the Kerguelen
Islands, which is considered a distinct subspecies. |
|
| HABITAT: |
Typically
found in shallow, coastal waters of the sub Antarctic. |
|
| POPULATION: |
GLOBAL |
No
data |
| LOCAL |
No
data |
|
| STATUS: |
IUCN |
Listed
as data deficient |
| CITES |
Appendix
II |
| USFWS |
Not
listed |
|
|
|
| |
|
|
| 1. |
Commerson's
dolphins typically eat 3.5-6 kg (8-13 lbs) of food
per day. This is proportionally a much greater amount
than either killer whales or bottlenose dolphins
ingest each day, and is due to Commerson's having
a metabolic rate that is two to three times higher
than many other whale or dolphin species. |
|
|
| 2. |
The first Commerson's dolphin calf ever born in
a marine zoological environment was born at SeaWorld
San Diego on February 21, 1985. The calf weighed
approximately 9 kg (20 lbs) and measured 61 cm (2
ft). |
|
|
| 3. |
Commerson's dolphins are fast and highly maneuverable
cetaceans regularly swimming at speeds of 11-13
kph (7-8 mph). These dolphins are commonly seen
wave-riding in the bows or wakes of high-speed boats,
shoreline breakers or groundswells. |
|
|
| 4. |
Commerson's
dolphins are typically found alone or in small groups
of two to three animals and occasionally spotted
in larger groups of 20-30 or more dolphins. They
often hunt cooperatively either encircling fish
and taking turns passing through to feed on the
clustered fish or even driving fish onshore and
temporarily stranding themselves to snatch up the
fish. |
|
|
|
| |
|
|
| Within
their range, Commerson's dolphins are considered
fairly common. However, some are inadvertently caught
and killed in fishing nets throughout part of their
range, especially off the coast of Argentina. In
the past, local fishermen intentionally caught these
dolphins for food, oil or bait. Now that this practice
is illegal, the rate of hunting for Commerson's
dolphins has allegedly declined. Yet, it is not
known how much the accidental catch from Commerson's
entangled in fishing gear still continues to affect
population numbers. In some parts of their range,
Commerson's dolphins have been found with elevated
levels of industrial pollutants, which may also
pose a threat to population numbers.
As
with other species of cetaceans, international
laws protect Commerson's dolphins.
|
|
|
|
| |
|
|
| Jefferson,
T.J. Leatherwood, S. and M.A. Webber. FAO Species
identification Guide. Marine Mammals of the World.
Rome. FAO, 1993. |
|
|
Leatherwood, Stephen, and Reeves, Randall R. The
Sierra Club Handbook of Whales and Dolphins.
San Francisco: Sierra Club Books, 1983. |
|
|
Nuzzolo,
D. The Commerson's Dolphin Story. San Diego.
Sea World, Inc. 2004.
|
| |
| 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. |
|
| http://animaldiversity.ummz.umich.edu |
|
|
|
|
|
