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Polar Bear (Ursus maritimus) Fact Sheet: Taxonomy & History

Taxonomic History & Nomenclature


  • See side bar
  • No subspecies recognized

Scientific name

  • Ursus maritimus, from Latin for "sea bear"


  • Thalarctos maritimus (Wiig et al. 2015)

Local names

  • Many names throughout Arctic:
    • Ah tik tok - Alaskan Eskimo name meaning "those that go down to the sea"
    • Nanook
    • Ice bear
    • Sea bear

Evolutionary History

Evolutionary relationships

  • Polar Bears and Brown Bears (U. arctos) comprise a sister group to Black Bears (Krause et al. 2008; Miller et al. 2012; Cronin et al. 2014)
    • Also related to the extinct Cave Bear (U. speleaus) (Krause et al. 2008; Agnarsson et al 2010)
  • Lineages leading to the 6 distinct living bear species in Ursus radiated from a common ancestor 6.3 million years ago (Pliocene).
    • Distant ancestors: Molecular data indicate that the procyonid (raccoons, koatis, ringtails, kinkajous and others) and bear families diverged from each other about 30 million years ago (Oligocene).
  • Brown Bears (includes Grizzly Bears) and Polar Bears diverged from the Black and Sun Bears in the last 5-6 million years (Pliocene)
    • Range overlap of Polar and Grizzly Bears only in Canada, Chukotka, Russia and Alaska (Clark et al. 2019)
    • Pleistocene-era evidence of gene flow between brown and polar bears
    • Current-day observations of a few polar bear-grizzly bear hybrids in western Canadian Arctic (Pongracz et al. 2017a)
  • Exact time period when Polar Bears diverged from Brown Bears unclear
    • Repeated gene flow between Polar Bears and Brown Bears throughout their history
    • Current estimates range from 150,000 to 600,000 years ago
      • Lindquist et al. (2010) and Lan et al. (2022) suggest Polar Bears diverged from Brown Bears approximately 150 thousand years ago [molecular evidence from a jawbone]
      • Liu et al. (2014) suggest Polar Bears diverged from Brown Bears approximately 400 (343 to 479) thousand years ago [genetic sequencing data]
      • Hailer et al. (2012) suggest Polar Bears are an old and distinct lineage, diverging from Brown Bears approximately 600 (338 to 934) thousand years ago
  • Polar Bears diverged from one group of brown bears about 150,000 years ago, according to molecular evidence (Lindquist et al 2010; Lan et al. 2022)
  • Modern polar bears rapidly expanded throughout the Arctic since the Late Pleistocene (Lindquist et al 2010)

Fossil history

  • Some fossils date back to as long ago as 130,000 years (Kurtén 1995; Ingolfsson and Wiig 2009; Lindqvist et al 2010; Lan et al. 2022)
    • In 2004, a well-preserved 110,000-130,000-year-old jawbone and canine tooth were discovered in the Svalbard archipelago of Norway and provided DNA

Cultural History

Documentary appearances

  • Polar Bear Alert - 2008, National Geographic
    • This DVD exclusive takes viewers on a journey to a small Canadian village, where residents have learned to live with a unique wildlife problem. Polar bears migrate through this small, isolated village. Scientists are presented with a unique opportunity to observe the bears.
  • Bears of the Last Frontier: Part 3, Arctic Wanderers - 2011, PBS
    • The polar bear learns how to survive in an everchanging environment in this Nature series from season 29.
  • Frozen Planet - 2012, BBC
    • This 7-part DVD has David Attenborough narrating the wilderness of the Arctic and Antarctic.
  • Polar Bear: A Summer Odyssey - 2012, CBC's Science and Natural History Documentary Unit.
    • Nominated for and Emmy and shot over twelve months, this documentary tells the story of a young polar bear's journey as he struggles to survive the longest Arctic summer on record.
  • The Polar Bear Family and Me - 2013, BBC
    • Gordon Buchanan follows a polar bear family from Spring, Summer, and Autumn in Svalbard.


  • Lords of the Arctic: A Journey Among the Polar Bears - Davids, 1982
  • Polar Bear - Matthews & Guravich, 1993
  • Polar Bears: A Complete Guide to Their Biology and Behavior - Derocher & Lynch, 2012

Children's books

  • Polar Bear, Polar Bear, What Do You Hear? - Martin Jr. & Carle, 1997
  • Polar Bears - Newman, 2010


Kingdom: Animalia

Phylum: Chordata

Class: Mammalia — mammals

Order: Carnivora (Bowdich, 1821) — carnivores

Family: Ursidae (Fischer de Waldheim, 1817) — bears

Genus: Ursus (Linnaeus, 1758) — bears

Species: Ursus maritimus (Phipps, 1774) — polar bear, white bear

Describer: Phipps (1774:p.185) A Voyage Towards North Pole, London: J. Nourse for Ursus maritimus

Sources: ITIS (2023)

Recommended Reading

Book cover for "Ice Bear"

Ice Bear: The Cultural History of an Arctic Icon by Michael Engelhard (2017)

A deep dive into the cultural history and conservation of polar bears.

San Diego Zoo Wildlife Alliance staff and volunteers
Email the SDZWA Library ( to request this book.

Page Citations

Agnarsson et al (2010)
Ingolfsson & Wiig (2008)
Krause et al (2008)
Yu et al (2007)
Lindquist et al (2010)
O'Brien (2003)
Schliebe et al (2006)
Wozencraft (2005)
Yu et al (2004)
Yu et al (2007)
ITIS (2010)

SDZWA Library Links