Nothing Eileen Oldaker tried could calm her mother when she called from the nursing home, disoriented and distressed in what was likely the early stages of dementia. So Ms. Oldaker hung up, dialed the nurses’ station and begged them to get Paro.

Paro is a robot modeled after a baby harp seal. It trills and paddles when petted, blinks when the lights go up, opens its eyes at loud noises and yelps when handled roughly or held upside down. Two microprocessors under its artificial white fur adjust its behavior based on information from dozens of hidden sensors that monitor sound, light, temperature and touch. It perks up at the sound of its name, praise and, over time, the words it hears frequently.

“Oh, there’s my baby,” Ms. Oldaker’s mother, Millie Lesek, exclaimed that night last winter when a staff member delivered the seal to her. “Here, Paro, come to me.”

“Meeaakk,” it replied, blinking up at her through long lashes.

Janet Walters, the staff member at Vincentian Home in Pittsburgh who recalled the incident, said she asked Mrs. Lesek if she would watch Paro for a little while.