The Washington Post on Instagram: "When scientists in Canada came across a female polar bear with two cubs in the fall, they made an unusual discovery: One of the young was not her own offspring but instead a rare documented example of an adopted cub. The mother, who is believed to be around five years old, was seen with one cub this spring, according to Polar Bears International, a nonprofit organization dedicated to polar bear conservation. But when scientists caught up with her again in the f