Thursday, January 26, 2012

Dusky Dolphin

Lagenorhynchus obscurus
The Dusky Dolphin is a small little Cetacean that rarely grows longer than 2m. They can be found in coastal waters throughout the Southern Hemisphere, and are divided into three subspecies based on location. These groups live near New Zealand, in the Indian Ocean, and off of South America.

The species is known for its acrobatic skill and they are frequently seen leaping and jumping in groups. They are also very fond of boats, and like to swim and tumble alongside them. Dusky Dolphins are fast swimmers, and can reach speeds of up to 20 knots.

Dusky Dolphins live in interesting social groups. At night when they swim closer to shore their group is very small, numbering somewhere between 6 and 15 individuals. But during they day they swim to deeper water and join up with other groups in order to cooperatively hunt, play, and socialize. These gatherings can include several hundred dolphins. At night they break up again into their smaller sections.

The small social groups themselves seem to be strong, but there are no strong bonds between mated pairs. Dusky Dolphins are promiscuous breeders, and males compete with each other over females.

There are no good population estimates for the Dusky Dolphins. As a result, we don't know for sure how much hunting for food and bait, and gill-net tangling has affected their numbers.

IUCN Status : Data Deficient
Location : Coastal waters in the Southern Hemisphere
Size : Length around 6ft (1.8m)
Classification : Phylum : Chordata --Class : Mammalia -- Order : Cetacea
Suborder : Odontoceti -- Family : Delphinidae -- Genus : Lagenorhynchus -- Species : L. obscurus

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