Humans aren't the only ones whose routines have been upended by the pandemic.

While lockdowns have forced zoo and aquarium visitors to stay home, the animals appear to have noticed that they have the place to themselves. Some of them seem to miss people, staff say, while others don't exactly seem to mind that no one is tapping on the glass.

"It completely surprised me," said Beth Schaefer, director of animal programs at the Los Angeles Zoo, when she observed animals including a curmudgeonly black bear and red river hogs seeming to peer around in the sudden quiet.

"We always think, 'The animals don't really pay that much attention to visitors. They just kind of do their own thing.' And then when the zoo is empty, it's like, 'Oh, wow, they actually respond or look at visitors more than we thought,'" said Mary Yoder, collection manager of primates at Arizona's Phoenix Zoo.