Lagenorhynchus australisPeale's dolphin

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Geographic Range

Lagenorynchus australis lives mostly in the mildly cold and temperate waters off of South America and the Falkland Islands in the South Atlantic Ocean. One sighting has been reported near the Cook Islands also. (Nowak, 1999; Reeder and Wilson, 1993)

Habitat

L. australis is usually found near the coast. These dolphins love to swim in and around the channels within kelp beds. They have also been sighted around sandbars and shallow bays. Most sightings of L. australis occur while there are strong tidal currents and during medium tides.

Peale's dolphins tend to inhabit two types of coastline. In the south they are usually found near channels and fjords. In the northern and eastern coast ranges, where the continental shelf underwater is very wide, they tend to be found in the open coast. In the open coast they have been found to swim as deep as 300 meters. There is little kelp there, but more southward and towards the Falkland Islands there are many kelp beds and this is where you will mostly find L. australis. (de Haro and Iniquez, 1997; Goodall, et al., 1997a; Goodall, et al., 1997b; Lescrauwaet, 1997; Nowak, 1999; Reeder and Wilson, 1993)

  • Range depth
    300 (high) m
    984.25 (high) ft

Physical Description

L. australis has many distinguishing physical characteristics. Some of these include a torpedo shaped body, a dark gray back, a white belly, a light gray area on flanks that extends from behind to the anus and a skinny white band that begins behind the dorsal fin and gets wider as it extends backwards. This latter feature is termed the “tail stock”.

L. australis has double black rings around both eyes and that extend forward to the nose. A final distinguishing feature that separates this species from other similar looking species is a circular patch of varying gray colors that is right on the thoracic area of the back.

The young of L. australis tend to look the same as the adults, but are much lighter in color. They become darker as they mature.

The teeth of L. australis seem to be variable. The maximum number on each upper jaw is thirty-seven and thirty-six on each lower jaw. Many teeth are hidden in the gums of the mouth.

The pectoral fin length is approximately 30 cm, and the dorsal fin can be up to 50 cm in height. The tail fluke is generally 30-60 cm wide, and the beak is up to 5 cm in length.

These animals may weigh up to 115 kg. (de Haro and Iniquez, 1997; Goodall, et al., 1997a; MacDonald, 1984; Nowak, 1999)

  • Average mass
    115 kg
    253.30 lb
  • Range length
    150 to 310 cm
    59.06 to 122.05 in

Development

Very little has been recorded about the developmental cycle in L. australis. The only studies recorded represent measurements of the ovaries of a few female L. australis. These measurements were representative of the different sexual maturities and the data showed the older females as having more ovarian scars. Even less information has been gathered about males and their sperm activity. There was not enough conclusive information to make any statements. No information has been collected about the young in L. australis and there have been no specimens collected or found with a fetus inside. Because of this we are left to assume that this species is similar in the developmental patterns of better-known dolphin species.

(Goodall et al, 1997 and Claver et al, 1992)

Reproduction

Little is known bout the mating system of these animals.

In general it has been noted that species within the genus Lagenorynchus have gestation periods of ten to twelve months. Calving season for L. australis usually occurs between the southern spring and autumn but a calf can be born as early as October. Females tend to have only one calf per birth (maybe two) and they also move more inshore to do this. Some records show that when two of these dolphins were spotted together in the past, they were only considered a mother and calf if the smaller of the two animals was one third or less the size of the adult accompanying it. On visual sightings alone, this is probably still the most common way to tell a calf from an adult.

Although data are not available for this species, in another member of the genus, L. acutus, young are between 90 and 125 cm at birth. They nurse for about 18 months, and become independent of their mothers around the age of 2 years. It is not known whne these animals mature sexually. (Goodall, et al., 1997a; Goodall, et al., 1997b; Nowak, 1999)

  • Breeding season
    It is not known for certain when mating occurs, but births occur during the Southern Spring to Autumn.
  • Range number of offspring
    1 to 2
  • Average number of offspring
    1
  • Range gestation period
    10 to 12 months

Young are precocial and swim along side of their mothers from birth. The mother provides her calf with milk for approximately 18 months, although the calf may remain dependent upon her for an additional 6 months. It is not known what role males play, if any, in the parental care of this species. (Nowak, 1999; Nowak, 1999)

  • Parental Investment
  • precocial
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
  • extended period of juvenile learning

Lifespan/Longevity

Scientists are able to determine the age of Peale's dolphins by looking at their teeth but no records or studies explain how this is accomplished. The oldest recorded specimen of L. australis was thirteen years old. (Goodall, et al., 1997a; Goodall, et al., 1997b)

  • Range lifespan
    Status: wild
    13 (high) years

Behavior

L. australis display many different types of behavior. When swimming L. australis is known for jumping, humping, spinning, and tailslapping. Some tail slaps are believed to aid foraging by directing fish towards other dolphins.

These animals tend to be gregarious and swim in small groups from 1 to 13 individuals. Most sightings are of groups with 2 to 4 members. In the summer months the average group size is 2 members. Some groups as large as 100 members have been recoreded. When such large aggregations occur, the dolphins tend to divide themselves up into sub-groups. Larger groups tend to be sighted more often in the months of January and February.

When swimming L. australis will surface about three to four times per minute and dive between one and 130 seconds. The average dive lasts less than 60 seconds.

The young have been seen surfacing a few more times a minute than the adults. When coming up from a dive, they expose only their blowhole and a part of the dorsal fin. Groups tend to surface together as if in some sort of rhythmic pattern.

When swimming rapidly Peale's dolphins display a behavior where water splashes up high around their faces, and they have accordingly been nicknamed "plow share dolphins".

When floating these animals tend to lay on their sides so they can look up at the boats around them. L. australis is very social around all kinds of boats and are often seen playing or swimming around them.

Individuals often follow in the wake of a boat, but once the propeller is turned off the dolphins' interest seems to subside.

L. australis has been known to interact with many species of ocean life including the following:

Commerson's dolphins (Cephalorynchus commersoni)

Southern right whales (Eubalaena australis)

Great grebes (Podiceps major)

Megellanic penguins (Spheniscus magellanicus)

Kelp gulls (Phalacrocorax magellanicus and Larus dominicanus)

South American sea lions (Otaria flavescens and Otaria flavescens)

Imperial shags (Phalacrocorax atriceps)

Rissos dolphins (Grampus griseus).

Many of these interactions are for playful purposes but some are for the sole purpose to help them catch their food. (de Haro and Iniquez, 1997; Goodall, et al., 1997a; Goodall, et al., 1997b; Nowak, 1999; Schiavini, et al., 1997)

Home Range

The home range size of these animals has not been reported.

Communication and Perception

Sounds emitted under water by L. australis include low frequency clicking noises and a "rapid tonal sound", but no whistling. There is little research on vocalizations, as they seem to be very timid communicators around boats taking the data. (Goodall, et al., 1997a; Goodall, et al., 1997b)

Food Habits

Peale's dolphins may feed in groups or alone. It has been hypothesized that this species may tend to feed alone when food is scarce and in groups when food is of abundance. When in groups, L. australis usually exhibits what is called "flower" or "starburst" feeding. They encircle their prey until they form a large group and then they feast. This is mostly done within the kelp beds. When they are sighted eating alone it is usually close to shore. When diving for prey it has been reported that they stay under water from between 10.36 seconds to 1.46 minutes.

Not very many L. australis have been dissected for examining the stomach contents, but known prey species are very extensive all the same.

Foods eaten include: Pleoticus muelleri (Argentine shrimp), squid (Loligo gahi and Illex argentinus), Kingklip fish (Genypterus blacodes), Argentine hake (Merluccius hubbsi), southern cod (Salilota australis), hagfish (Myxine australis), Pantagonian grenadier (Marcuronus magellanicus), red octopus (Enteroctopus megalocyathus), other species of herring, makarel, capelin, anchovies, crustaceans and whelks (gastropods). (de Haro and Iniquez, 1997; Nowak, 1999; Schiavini, et al., 1997)

  • Animal Foods
  • fish
  • mollusks
  • aquatic or marine worms
  • aquatic crustaceans

Predation

There are no known predators of L. australis.

Ecosystem Roles

There is so little known about Peales dolphins that their effect on the pelagic ecosystem is unknown. However, because they prey upon a number of types of animals, there is a potential impact of these dolphins upon prey populations. (Goodall, et al., 1997a; Goodall, et al., 1997b)

Species Used as Host
  • Anisakis simplex

Economic Importance for Humans: Positive

Humans have occasionally harpoon Peales dolphins for use as bait. (Goodall, et al., 1997a; Goodall, et al., 1997b)

Economic Importance for Humans: Negative

It is difficult to speculate on how these acquatic mammals might negatively impact humans. There are no reports of negative interactions, but it is possible that through their predatory behavior, populations of Peale's dolphins could negatively impact commercial or subsistence fisheries. However, this is just speculation, and there are no reports of this being the case.

Conservation Status

Lagenorynchus australis has not been studied intensively to determine population trends. There are a few human sources of mortality that may be of a concern in the future. These include shore-set gill nets (accidental catch), inshore fishing (incidental catch), and salmon farms near Chile (a few have been caught in the anti-pinniped nets despite the loud sounds made underwater to deter them). Deep sea fishermen have been known to occasionally catch a few Peales dophins in their mid-water nets. A more serious situation is occurring near crab fisheries where the use of nets has been outlawed. Fisheries have been known to use harpooned L. australis as bait. (Nowark, 1999 and Goodall et al, 1997)

Other Comments

There are many other common names for this species beside the common name Peales dolphin. These are Peales Porpoise, black-chinned dolphin, and Southern white-sided dolphin. In Spanish it used to be called llampa or tunina in Chile. Now it is called delfin austral (southern dolphin) in Chile and Argentina.

(Goodall et al, 1997)

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Heather Floyd (author), California State University, Sacramento, James Biardi (editor), California State University, Sacramento.

Glossary

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.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

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.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

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.

fertilization

union of egg and spermatozoan

internal fertilization

fertilization takes place within the female's body

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).

molluscivore

eats mollusks, members of Phylum Mollusca

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

piscivore

an animal that mainly eats fish

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

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).

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

young precocial

young are relatively well-developed when born

References

Claver, J., M. Iniguez, D. Lombardo, I. von Lawzewitsch. 1992. Preliminary Observations on Ovarian Activity and Sexual Maturity in Female Peale's Dolphin (Lagenorynchus australis). Aquatic Mammals, 18: 85-88.

Goodall, R., K. Norris, W. Schevill, F. Fraga, R. Praderi. 1997. Review and Update on the Biology of the Peale's Dolphin, Lagenorynchus australis. International Whaling Commission Report, 47: 777-796.

Goodall, R., J. de Haro, F. Fraga, M. Iniquez, K. Norris. 1997. Sightings and Behavior of Peale's Dolphins, Lagenorynchus australis, with Notes on Dusky Dolphins, L. obscurus, off Southern Most South America. International Whaling Commission Report, 47: 757-775.

Lescrauwaet, A. 1997. Notes on the Behavior and the Ecology of the Peale's Dolphin, Lagenorynchus in the Strait of Magellan, Chile. International Whaling Commission Report, 47: 747-755.

MacDonald, D. 1984. Encyclopedia of Mammals. N.Y.: Facts on File Publications.

Nowak, R. 1999. Walkers Mammals of the World, Sixth ediition. Baltimore and London: Johns Hopkins University Press.

Reeder, D., D. Wilson. 1993. Mammal Species of the World ed. 2. Washington and London: Smithsonian Institution Press.

Schiavini, A., R. Goodall, A. Lescrauwaet, M. Koen Alonso. 1997. Food Habits of the Peale's Dolphin, Lagenorynchus australis; Review and New Information. International Whaling Commission Report, 47: 827-834.

de Haro, J., M. Iniquez. 1997. Ecology and Behavior of the Peale's Dolphin, Lagenorynchus australis (Peale, 1848), at Cabo Virgenes (52 degrees 30' S., 68 degees 28'W), in Patagonia, Argentina. International Whaling Commission Report, 47: 723-727.