Students and teachers are welcome to borrow these low-resolution photos for non-commercial uses.  There is no need to ask permission, just  "Photo credit WilliamCalvin.com."   Right-click on an image and save it to disk.   Except as noted, all photographs are by William H. Calvin.

Large guts are needed to process 50 pounds per day of low quality food (leaves, bamboo) in the wild.

The 570-pound silverback carries zoo food back to his favorite spot at the San Diego Wild Animal Park.

The built-in eyeshade.

When I say "jump," soldier,
I want to hear you say "How high, sir?"
(Actually, this is grooming, using lips.)