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The memory of elephants is the stuff of lore, and now it seems they can recall the smell of a relative even after a decade apart.

When at the University of Wuppertal in Germany and her colleagues heard about planned reunions between two mother-daughter pairs at zoos in Germany, they took advantage of the chance to test the elephants’ memories. One pair had been separated for two years, while the other had spent 12 years apart.

Hörner collected faecal samples from these African elephants (Loxodonta africana) and others at German zoos, hauling the stinking 10-to-15-kilogram stools around in her tiny car.

Her team presented these samples one at a time to the four elephants in advance of their reunions with family members. When they encountered heaps of faeces from unrelated elephants, either those in the same zoo or unfamiliar animals, they sniffed the dung piles and walked away.

But when presented with a sample from the mother or daughter they were due to be reunited with, the female elephants repeatedly sniffed the samples and showed a variety of reactions, from rumbling sounds to flapping their ears.

Such reactions may be linked to positive emotions, the researchers say. “That was amazing and really intense,” says Hörner. “We were sure they do remember, and they know exactly what they are smelling there.”

The sample size was small, but it would be cruel to do similar tests on elephants that weren’t being reunited, says Hörner. “It might trigger something in them.”

“I am not surprised that elephants have memories, especially in social contexts, that last a long time,” says at Hunter College in New York, who wasn’t involved with the work. Elephants live in groups that split up and come back together over long periods of time.

But Plotnik says the experiment may not be a true test of memory. Perhaps there are scent cues common to all kin that can trigger recognition not linked to memory, he says. Presenting the elephants with a slew of other smells, such as their own, other absent kin, present relatives and more samples from unfamiliar elephants, would help make sense of the elephants’ responses.

Whether or not the experiment itself passes the smell test, the protocol may be useful for introducing new elephants to zoo populations. Elephants in zoos can be hesitant about newcomers. “That would be actually pretty smart to spread the scent around the whole enclosure,” says Hörner.

For the elephants in this experiment, the reunions were a success, says Hörner. The mothers and daughters greeted each other almost immediately by embracing with their trunks.

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