The elephant seal was exhausted after a long journey. The massive bull, one of the first to arrive for the annual mating season, had hauled out at Chimney Rock on Saturday to enjoy a few refreshing winks. His nap was rudely interrupted when a woman at the Lifeboat Station began hurling rocks at him—seemingly for a photo op. Her assault, launched from a deck above the beach, was captured on a grainy video camera operated 24/7 by the Marine Mammal Center. In the video, the woman, wearing a white baseball cap, throws one rock after another at the animal while a male companion stands nearby shooting pictures with a long-lensed camera. Fortunately for the seal, she had lousy aim, and the barrage did not appear to harm him. But the twisted episode sparked outrage among those who saw it on Twitter, where someone posted a clip. “To the woman throwing 30+ rocks at the bull elephant seal on Point Reyes beach: Shame on you. I hope next time you’re exhausted, rocks are thrown in YOUR direction. Absolutely shameful. Harassing marine mammals is a federal crime.” A viewer in Japan who happened to see the incident on the webcam sent an email to the center, whose staff reported the episode to the National Park Service and NOAA’s office of law enforcement. Both agencies are investigating the incident, according to Earl Perez-Faust, a spokesman for the park. “This type of severe harassment behavior—throwing rocks at wildlife—is both disturbing and alarming,” said Giancarlo Rulli, a spokesman for the Marine Mammal Center. “It is a rare occurrence not often sighted or reported across our 600-mile California response range. Thankfully, in this case it was reported and caught on camera. It’s illegal and fineable under the Marine Mammal Protection Act.” Mr. Perez-Faust encouraged visitors to report wildlife harassment by calling the dispatch center at (415) 464.5170 or otherwise informing park staff. The northern elephant seal pupping season on Point Reyes runs from December through March. Males arrive first to stake a claim on a patch of beach they intend to dominate, migrating from as far as 14,000 miles away. Last year, park staff counted 1,063 weaned pups on a single day in March.