Geographic Range
Spectacled porpoises are rarely seen and are found only in the oceans of the southern
hemisphere. Usually they are found near the southern east coast of South America
(from Uruguay and Argentina to Cape Horn) and also near the Falkland Islands and South
Georgia.
Australophocaena dioptrica
have been seen near New Zealand, Macquarie Island and the Auckland Islands in the
Pacific Ocean, and Heard Island and the Kerguelen Islands in the Indian Ocean.
- Biogeographic Regions
- indian ocean
- atlantic ocean
- pacific ocean
Habitat
Spectacled porpoises prefer cold ocean waters of the southern hemisphere. They normally
live near offshore islands but are sometimes found in the open ocean. They seem to
prefer the subantarctic area where there are cold currents like the Falkland Current.
- Habitat Regions
- temperate
- saltwater or marine
Physical Description
Size of this species can vary from about 1.25 meters (females) to 2.24 meters (males).
The average weight of
A. dioptrica
varies from 55 to 80 kilograms; the largest individual found was 115 kilograms. The
dorsal side is a blue-black color and the ventral side is pure white. There is a
sharp line that divides the dorsal black color from the ventral white color. There
is a gray line that goes from the corners of the mouth to the leading edge of the
pectoral flippers, which are white. The lips are also black and the eyes are surrounded
by black circles that look like glasses. The tail fluke is dark on the top side and
white on the bottom. Shape also distinguishes this species. The dorsal fin is big
and triangular and the pectoral fins are small and rounded when compared to other
Phocoena
species. The teeth in the upper jaw number between 18 and 23 and the teeth in the
lower jaw number between 16 and 19 on each side. The teeth have spade-shaped crowns,
which is a distinguishing characteristic of
porpoises
when compared to
dolphins
, which have cone-shaped crowns. There also are some skull features that distinguish
A. dioptrica
from
P. phocoena
: the top of the rostrum of
A. dioptrica
is flatter, and from the side, the premaxillary bones of
A. dioptrica
are less visible.
- Other Physical Features
- endothermic
- homoiothermic
- bilateral symmetry
- Sexual Dimorphism
- male larger
Reproduction
No information is available on the mating systems of this species.
All mammals reproduce sexually via internal fertilization and all eutherian mammals
give birth to live young. However, very little else is known about the reproductive
behaviors of
A. dioptrica
. One near-term fetus was recorded in July 1912 and another was taken in August of
the same year. The first fetus was a female and was 484 millimeters long. No information
was recorded on the second fetus. The young are most likely born in early spring,
but no information is recorded.
- Key Reproductive Features
- iteroparous
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- fertilization
- viviparous
A feature common to all eutherian mammals is that females nuture their young inside their bodies until birth, and afterwards provide them with milk. However, no specific information on parental investment is available for A. dioptrica .
- Parental Investment
-
pre-fertilization
- provisioning
-
protecting
- female
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-weaning/fledging
-
provisioning
- female
-
protecting
- female
-
provisioning
Lifespan/Longevity
The lifespan of A. dioptrica is unknown.
Behavior
This species does not travel in large groups. They are probably solitary animals,
but they have been seen in groups of two or three individuals. They are probably not
migratory.
- Key Behaviors
- natatorial
- motile
- solitary
- social
Communication and Perception
Nothing has been recorded about the communication or perception of A. dioptrica , but they probably use echolocation as do other porpoises.
- Perception Channels
- tactile
- echolocation
- chemical
Food Habits
The food preferences of spectacled porpoises are not well known. They are most likely
similar to other porpoises, which eat
fish
,
squid
, and
crustaceans
.
- Animal Foods
- fish
- mollusks
- aquatic crustaceans
Predation
Nothing is recorded about predation of
A. dioptrica
. It is possible that
killer whales
are their only natural predators. They also are hunted by humans.
Ecosystem Roles
Porpoises are predators of fish and aquatic invertebrates, and they sometimes provide a food source to killer whales. Nothing specific is known about the role of A. dioptrica in the ecosystem.
Economic Importance for Humans: Positive
Native people in South America hunt
A. dioptrica
, but not for commercial uses.
- Positive Impacts
- food
Economic Importance for Humans: Negative
Spectacled porpoises have no recorded adverse affects on humans.
Conservation Status
Not enough information is known about this species in order to list it as endangered.
Other Comments
Spectacled porpoises were previously known as
Australophocaena dioptrica
and
Phocoena storni
. Their Spanish common name is Marsopa de Anteojos.
Additional Links
Contributors
Allison Poor (editor), University of Michigan-Ann Arbor.
Jennifer Nixon (author), University of Northern Iowa, Jim Demastes (editor), University of Northern Iowa.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- Atlantic Ocean
-
the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- Pacific Ocean
-
body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- temperate
-
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
- saltwater or marine
-
mainly lives in oceans, seas, or other bodies of salt water.
- pelagic
-
An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).
- coastal
-
the nearshore aquatic habitats near a coast, or shoreline.
- endothermic
-
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- iteroparous
-
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- fertilization
-
union of egg and spermatozoan
- viviparous
-
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
- natatorial
-
specialized for swimming
- motile
-
having the capacity to move from one place to another.
- solitary
-
lives alone
- social
-
associates with others of its species; forms social groups.
- tactile
-
uses touch to communicate
- echolocation
-
The process by which an animal locates itself with respect to other animals and objects by emitting sound waves and sensing the pattern of the reflected sound waves.
- chemical
-
uses smells or other chemicals to communicate
- food
-
A substance that provides both nutrients and energy to a living thing.
- carnivore
-
an animal that mainly eats meat
- piscivore
-
an animal that mainly eats fish
References
Bannister, J., C. Kemper, R. Warneke. September 1996. "The Action Plan for Australian Cetaceans" (On-line). Accessed November 28, 2001 at http://www.deh.gov.au/coasts/species/cetaceans/actionplan/whaleap5a.html .
Brownell, R. November 21, 1975.
Coffey, D. 1977. Dolphins, Whales and Porpoises: An Encyclopedia of Sea Mammals . New York: Macmillan Publishing Co., Inc..
Minasian, S., K. Balcomb, L. Foster. 1984. The World's Whales: The Complete Illustrated Guide . Washington, D.C.: Smithsonian Books.
Nowak, R. 1999. Walker's Mammals of the World . Baltimore and London: Johns Hopkins University Press.
Tinker, S. 1988. Whales of the World . Honolulu, Hawaii: Bess Press Inc..