Published December 18, 2023
6 min read
Meet Louise, a bonobo who has shattered records with her incredible social memory.
Louise, born in captivity at the San Diego Zoo, left her troop to start a family of her own, eventually being transferred to Japan’s Kumamoto Sanctuary in 1992. Over time, her family members became a distant memory as years passed by. But in 2019, that all changed.
Presented with a photo of her sister, Loretta, next to a stranger, Louise only had eyes for her kin, completely ignoring the unknown bonobo. The same happened when shown a photo of her nephew alongside a stranger – Louise showed little to no interest in the unfamiliar bonobo. Her preference for her family members was undeniable.
The incredible thing is, it had been 26 years since Louise had seen either of these family members. Yet, over multiple trials, she consistently chose to look at her long-lost relatives over bonobos she had never been housed with.
It’s a remarkable display of memory and emotion in a nonhuman animal, and it raises questions about the nature of social relationships in the animal kingdom.
Ultimately, this marks the longest-lasting nonhuman social memory ever documented, according to a study published today in the journal Proceedings of the National Academy of Sciences. The previous record belonged to bottlenose dolphins, which have been shown to recognize podmates’ vocalizations after 20 years.
Driven by years of experience working with great apes in captivity, scientists conducted eye-tracking experiments with bonobos and chimpanzees, presenting them with images of familiar animals they hadn’t seen in months or even decades. The results were groundbreaking, revealing not only the great apes’ remarkable memory but also the depth of the social bonds they had formed.
