Balaenoptera borealis   Lesson,  1828 (Whale)
Organism information awaits expert curation
Class: Mammalia

Size: Male: 13.7 m; Female: 15.6 m

Weight: 16-18 tons

Color: The Sei Whale is dark grey on the back and sides, marked with light colored scars. These scars may give its body a metallic look. The animal is pale below. A region of the belly is grayish-white.

The body is slim and streamlined. The narrow head is slightly arched, with a single prominent ridge extending from the blowholes to the tip of the snout. A few hairs are present on both the jaws and the snout. This species has 32-60 throat grooves, all ending well before the navel. The flippers are relatively small, about one-eleventh of the body length, and pointed. The tail flukes are relatively small. The dorsal fin is 25-60 cm tall, hooked, and placed slightly less than two thirds along the back.

There are 300-410 ash-black baleen plates with fine white fringes; these fringes are silky. Some Sei Whales have several half white plates near the front of the mouth, as do Fin Whales Balaenoptera physalus. The moderately tall spout (about 3 m high) is shaped like an inverted cone, and the dorsal fin is also seen almost simultaneously.

Calving occurs in mid winter; Weaning: 7 months

Family groups of 5 or 6 whales move together, and pair bonds are strong and may last from year to year.

Similar species: These are often confused with Bryde' s Whale and less often with Fin Whales. A careful observation of dorsal fin shape, shape of the head position and color pattern allow distinction.

Synonym (s)
Balaenoptera alba Giglioli, 1870
Balaenoptera arctica Temminck, 1841
Balaenoptera iwasi Gray, 1846
Balaenoptera laticeps Gray, 1846
Balaenoptera schlegelii Van Beneden & Gervais, 1880
Balaenoptera schlegellii Dabbene, 1902
Balena rostrata Rudolphi, 1822
Belaenoptera schlegeli Lahille, 1899
Pterobalaena alba Giglioli, 1874
Pterobalaena schlegeli alba Tomilin, 1957
Sibbaldius schlegelii Gray, 1864

Common Name (s)
• Rudolphi's Rorqual (English)
• Japan Finner
• Sardine Whale (English)
• Coalfish
• Pollack Whale (English)
• Short Headed Sperm Whale
• Thimingalam (Tamil)
• Sei Whale (English)
• Thimingalam
Economic Importance and Threats
Threats:  Anthropogenic

Habitat:  Open Sea, Coastal
Prey:  Plankton, fish, squid, euphausiids, copepods, amphipods, small fish.
IUCN Status:  Endangered


• Palk Bay INDIA (Record: 12/1971)
• Tamil Nadu, Dhanushkodi INDIA (Record: 1983)
• Tamil Nadu, Tuticorin INDIA (Record: 26/02/1988)
• Tamil Nadu, Gulf of Mannar INDIA (Record: 18/05/1988)
• Tamil Nadu, Dhanushkodi INDIA
• Palk Bay INDIA
• INDIA (Record: 1800-2000)
• Tamil Nadu, Gulf of Mannar INDIA

Literature Source(s)
  • Sathasivam K (2004) Marine mammals of India Universities Press(India) private limited, Hyderabad, India 180 pp Available at - NIO, Goa
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at -
  • (2003) IUCN Red list of threatened species Available at -
  • Borkar, M (2005) Marine mammals, turtles and crocodiles: A field manual NIO, Goa 63 pp Available at - NIO
  • Marine Biological Station, Chennai, Tamil Nadu (2003) Checklist of marine fauna of Tamil Nadu Department of Environment, Government of Tamil Nadu Available at -
  • Dr. Ramesh, R; Dr. Nammalwar, P and Dr. Gowri, VS (2008) Database on coastal information of Tamil Nadu Report Submitted to Environmental Information System (ENVIS) Centre, Department of Environment, Government of Tamil Nadu Institute for Ocean Management, Anna University, Chennai, Tamil Nadu. Available at -
  • Kumaran, PL (2002) Marine mammal research in India: A review and critique of the methods Current Science Indian Academy of Sciences, Bangalore 83(10) 1210-1220 Available at -
  • Dr. Kumaraguru, AK (2000) Studies on socioeconomics of Coral Reef resource users in the Gulf of Mannar coast, South India Centre for Marine and Coastal studies School of Energy, Environment and Natural Resources Madurai Kamaraj University, Madurai, India Available at -
  • Pillai, PKM and Augustine, SK (2000) A code list of common marine living resources of the Indian seas CMFRI Special Publication No.12 CMFRI 1-115 Available at -
  • Padmanaban P and Dinesh K.P (2011) A checklist of Marine Mammals of India Marine Biology Reginal centre, Zoological Survey of India 4pp Available at -
  • Jefferson, TA; Leatherwood, S and Webber, MA (2006) Marine mammals of the world World biodiversity database Available at -

Page last updated on:2012-11-07

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