Opossums were introduced from eastern US initially to California, then through range expansion or additional introductions are now common in Washington west of the Cascades.
Usually nocturnal and solitary, during the day opossums may hide in attics and under porches so you might see one around your house.
Climbs easily and uses its prehensile naked tail like an extra hand, especially in trees.
The young spend 3 months in a pouch like that of a kangaroo but backward-pointing (both are marsupials).
“Playing possum” is a phrase that refers their habit of acting dead when threatened.