The bleat not only alerts other pandas to the presence of an available mate, it contains important information about the vocalist’s size and identity. Given the dense bamboo thicket that limits visual contact in most panda habitats and the brevity of panda mating season — females ovulate just once a year and can conceive for only a few days — the pandas’ ability to perceive the bleat is critical to reproduction among this once-endangered species.

Now, researchers have determined that the bleat works best as a local call. A panda can discern aspects of a caller’s identity. like its size, from a bleat within about 65 feet, but the caller’s gender is only perceptible within about 33 feet, according to a study published Thursday in Scientific Reports.

Megan Owen, a conservation ecologist at the San Diego Zoo Institute for Conservation Research and an author of the study, offered a human analogy for how this ability works.

“If you’re walking into a crowded room and someone calls out your name, there’s a certain point where you can identify who that is, or maybe you can identify that it’s a male or female that is calling your name,” she said. “There’s information that’s encoded in that call, but that information degrades over distance.”

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To conduct the study, Dr. Owen and her colleagues — including Ben Charlton, another San Diego institute researcher who has studied panda bleats — obtained recordings of giant pandas from Chengdu, China, during breeding season. They then played those recordings through a speaker in a section of the San Diego Zoo Safari Park that contains bamboo similar in type and density to a typical panda habitat. By placing recording devices throughout the bamboo, the researchers were able to capture and analyze the bleats from various distances.