Lagenodelphis hoseiFraser's dolphin
Geographic Range
These dolphins are restricted to tropical and subtropical waters.
- Biogeographic Regions
- indian ocean
- atlantic ocean
- pacific ocean
Physical Description
- Other Physical Features
- endothermic
- bilateral symmetry
-
- 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.
- Key Reproductive Features
- iteroparous
- year-round breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- viviparous
-
- 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 (female)
-
- 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.
- Key Behaviors
- natatorial
- motile
- social
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
-
- IUCN Red List
-
Least Concern
More information
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.
- 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
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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
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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