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Australian Wildlife

  Sei Whale (Balaenoptera borealis)

SEI WHALE FACTS

Description
Sei whales are dark gray with irregular white markings across the back. The body is relatively slender with short pectoral fins and sickle shaped dorsal fin. The snout is pointed. On the underside of throat and chest is 38-56 grooves. The upper part of the mouth contains 300 - 380 grey-black baleen plates on each side. The plates have whitish bristles for trapping food.

Size
Length 12m - 15m. The largest known Sei whale was 20m.

Habitat
open ocean

Food
Feeds on krill and other small crustaceans, and also small fish. They swim on their side near the surface through swarms of prey. The food is trapped in its baleen plates. An average Sei whale eats about 900 kilograms every day.

Breeding
Breeding season is November and February in northern hemisphere and May and July in southern hemisphere. A single calf (rarely twins) is born after gestation of 10.5 months - 12 months. The calf is about 4.5m long at birth and is weaned after 6 - 7 months. They can live to 74 years old.

Range
all oceans except polar and tropical regions.

distribution map showing range of Balaenoptera borealis in Australia

Credits:
Map is from Atlas of Living Australia website at https://biocache.ala.org.au licensed under Creative Commons Attribution 3.0 License.

Conservation Status
The conservation status in the 2004 IUCN Red List of Threatened Animals is "endangered".

Classification
Class:Mammalia
Order:Cetacea
Family:Balaenopteridae
Genus:Balaenoptera
Species:borealis
Common Name:Sei Whale

Relatives in same Genus
  Dwarf Minke Whale (B. acutorostrata)
  Bryde's Whale (B. edeni)
  Blue Whale (B. musculus)
  Fin Whale (B. physalus)