The Sound of One Walrus Clapping

Spoiler: It’s very loud.

Starting in the late 2000s, Colleen Reichmuth and Ole Larsen made a number of visits to Six Flags Discovery Kingdom in Vallejo, Calif., to hear a walrus make some noise. The male Pacific walrus, named Sivuqaq, was approaching sexual maturity, which meant he might soon spout the signature din that male walruses make in breeding season. Dr. Reichmuth, a research scientist at the University of California, Santa Cruz, was driving a short way to see Sivuqaq. But Dr. Larsen, a bio-acoustician at the University of Southern Denmark, was traveling a long way from, well, Denmark. Dr. Reichmuth and Dr. Larsen had come specifically to hear Sivuqaq emit a male walrus’s characteristic breeding sounds: knocks, metallic gong-like beats and piercing whistles. But Sivuqaq, who stole the screen during appearances in “50 First Dates” with Adam Sandler and Drew Barrymore, was uncooperative. Some days, he clapped his fore flippers together thousands of times in a row while underwater, incessantly.