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Researchers Film Rare Polar Bear Adoption in Western Hudson Bay

Genetic tests now seek to pinpoint the cub’s origins to determine whether this was a litter switch or an orphaning.

Overview

  • Collared female X33991 was seen leaving her den in spring with one tagged cub, then re-sighted near Churchill in November with two similarly aged cubs, one untagged.
  • Video, photographs, and GPS data verified the adoption, and the three bears are now on the sea ice with both cubs appearing healthy at about 10–11 months old.
  • It is only the 13th documented adoption in roughly 45 years of monitoring about 4,600 bears in the Western Hudson Bay population, with just three prior adopted cubs known to reach adulthood.
  • Having a maternal caregiver substantially raises a cub’s survival prospects, and cubs typically remain with their mother for roughly two to two-and-a-half years.
  • Researchers collected genetic samples from the untagged cub and are analyzing them to identify its biological mother, with experts pointing to strong maternal priming—not climate-driven behavior—as the likely driver of such adoptions.