Illustration © Pieter Folkens
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Distribution/Migration: Worldwide. In North Pacific, migrate from winter breeding grounds in Hawaii, Japan, and Mexico to summer feeding grounds from Washington to Chukchi Sea. Pink shows summer range.
This web page is modified from the book Marine Mammals of Alaska by Kate Wynne, illustrated by Pieter Folkens, available at the Alaska Sea Grant Bookstore.
SIZE: Average adult male 46 ft (14 m), 25 tons. Average adult female 49 ft (15 m), 35 tons. At birth 16 ft (5 m), 2 tons.
BODY: Stocky body with flat, broad head. Series of fleshy knobs on rostrum and lower lip. Up to 400 two-foot-long (0.7 m) dark baleen plates per side and 12–36 ventral throat grooves. Flippers elongate (one-third body length) and flukes broad with irregular trailing edge.
COLOR: Body black with some white on throat and belly. Variable amount of white on flippers and flukes.
DORSAL FIN: Fin small, shape varies (can help distinguish individuals).
BLOW: Broad and bushy, to 10 ft (3 m) high.
BEHAVIOR: Often seen in groups of 2–12 but larger aggregations are common on both winter and summer grounds. Acrobatic: Breaching, spy-hopping, and lobtailing are common. Variety of vocalizations including complex songs.
DIVE PATTERN: Blow 4–10 times at 20–30 sec intervals between dives lasting 3–28 mins. Flukes show prior to deep dives.
HABITAT: Pelagic and coastal. Feed and breed over shallow banks but may traverse open ocean during migration.
FOOD HABITS: Prey on euphausiids and small schooling fish; some use bubbles to help capture prey.
LIFE HISTORY: Sexually mature at 4–7 yrs. Breed in winter. Single calf born every 1–3 yrs after gestation of 11.5 mos. Lactation lasts 6–10 mos. May live 50 yrs.
STATUS AND HUMAN INTERACTIONS: Endangered. Approx 6000–8000 in North Pacific and increasing. Vulnerable to vessel collisions and entanglement in buoyed lines and nets.