Dogs in city apartments have always had to adjust to less-than-ideal conditions, but the return to work has meant that suddenly thousands are going through the same transition at the same time, said Kate Senisi, the director of training at School for the Dogs in Manhattan’s East Village. “We’ve had a lot of separation cases coming through,” she said.

Dogs who were used to being left alone before the pandemic tend to adjust relatively quickly, she said. “But for the pandemic puppies” — dogs born and adopted during the pandemic — “they haven’t been left at all, and now they’re at a sensitive age, adolescence,” she said. “It can be pretty difficult. They have to be taught these new skills.”

Pro tip from the trainer: don’t give your dog that special toy only when you leave, because the toy will become a trigger for distress.