Bear cubs roughhouse on Siblings Day

Let's celebrate Siblings Day by peaking at the antics of these playful grizzly bear cubs (while staying clear of their mother). Pregnant female grizzlies settle into their den in winter and give birth while hibernating, usually to two cubs. While their mother sleeps, the cubs nurse and grow quickly. When springtime arrives, the new family emerges from the den to search for food. These siblings will cohabitate with their mother for two to three years, after which they’ll venture off on their own.
© Ron Niebrugge/Alamy