Lagenodelphis hoseiFraser's dolphin

Geographic Range

These dolphins are restricted to tropical and subtropical waters.

Physical Description

  • Average mass
    164000 g
    5779.74 oz
    AnAge

Reproduction

Breeding appears to be year-round with a possible peak in the summer months. The gestation period is thought to be about 11 months. Sexual maturity of both sexes occurs at about seven years of age. There is no sexual dimorphism except in the size and shape of the dorsal-fin, with male fins being larger than female fins.

  • Breeding season
    Breeding appears to be year-round with a possible peak in the summer months.
  • Average number of offspring
    1
    AnAge
  • Average gestation period
    11 months
  • Average gestation period
    335 days
    AnAge
  • Average age at sexual or reproductive maturity (female)
    7 years
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    2646 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    7 years

Behavior

No predation on this species has been observed, but killer whales, false killer whales and sharks probably occasionally take these dolphins as prey. Fraser's dolphins are often found with other whales, especially melon-headed whales, but also pilot whales and many other dolphin species. Groups tend to be large, ranging from 100-2500. When fleeing from ships, these dolphins can reach speeds of 28 km/h.

Communication and Perception

Food Habits

Fraser's dolphins primarily eat fish, but they also feed on squid, cuttlefish and shrimp. There is strong evidence that these animals prefer to feed at depths of 250-500 meters and rarely at the surface.

  • Animal Foods
  • fish
  • mollusks
  • aquatic crustaceans

Economic Importance for Humans: Positive

People in many Asian cultures hunt this species for food.

Economic Importance for Humans: Negative

Because they do not feed at the surface, they do not compete with fisherman for tuna or other pelagic fish.

Conservation Status

CITES Appendix 2

Contributors

Bret Weinstein (author), University of Michigan-Ann Arbor.

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

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.

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

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.

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).

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

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

viviparous

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

year-round breeding

breeding takes place throughout the year

References

Mammalian Species #470

Walker's Mammals of the World, fifth edition; Nowak, R. ed.; 1991; Johns Hopkins University Press. pp. 990-991