TACOMA, Wash. — An elated otter nibbling on bamboo. A clouded leopard pouncing on palm fronds. A baby musk ox doing zoomies in a pile of fall leaves. All of them are playing with plants grown at the ...

For a female muskox at the Port Defiance Zoo in Tacoma, Washington, a morning’s exercise can take many of forms. She can trot around her enclosure, hang out with her calf, or get a little game of ...