Illustration © Pieter Folkens
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Distribution/Migration: Arctic. In North Pacific, found seasonally in Cook Inlet, Bering, Chukchi, and Beaufort seas, often in or near ice. In summer, congregate in coastal and river systems. Pink shows summer range, blue shows winter range, and purple shows year-round.
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 13 ft (4 m), 3300 lbs. Average adult female 12 ft (3.7 m), 3000 lbs. At birth 5 ft (1.5 m), 100 lbs.
BODY: Stocky body with flexible neck. Small, rounded head with prominent melon and short beak. 40–44 conical teeth. Flippers broad and spatulate, edges curl with age. Flukes broad, notched, with convex trailing edges.
COLOR: Dark gray at birth, fade with age (blue-gray as juveniles) to completely white as adults (5–6 yrs).
DORSAL FIN: No dorsal fin. Narrow dorsal ridge along back, accentuated in older males.
BLOW: Low and inconspicuous, often heard rather than seen.
BEHAVIOR: Gregarious. Groups of 15–1000+ are common. Often associated with ice. Vocal but seldom acrobatic.
DIVE PATTERN: Slow swimmers, often roll casually at surface. May dive to 800 m.
HABITAT: Coastal, estuarine, or open ocean. Often near ice.
FOOD HABITS: Generalists. 100+ known prey species include fish, squid, crabs, and clams. Echolocate prey with sophisticated sonar.
LIFE HISTORY: Sexually mature at 5–8 yrs. Breed in spring. Single calf every 2+ yrs after gestation of 14 mos. Lactation lasts 1–2 yrs. May live 35 years or more.
STATUS AND HUMAN INTERACTIONS: Stable except for declines in Cook Inlet. Estimated 64,000 in Alaska waters. Alaska Natives harvest 200–400 annually for subsistence use. Coastal and river development, pollution, and net fisheries pose potential threats.