The librarian's son

Last night, as he was falling asleep, Isaac announced, "Both warthogs and wildebeests snort." Then he asked, "Do warthogs breathe?"

"Yes," I told him. "All animals breathe."

"Do even little babies breathe?"

"Yes," I told him. "We all need to breathe to stay alive."

"Why?"

"You know what, honey?" I told him. "I'm not sure why."

"But we can look it up!" he said cheerfully.