Elephants say 'hello' to friends by flapping their ears and making little rumbly noises

When elephants reunite with friends, they greet each other with ear flaps, rumbles and other deliberate sounds and gestures, new research shows.

The study, which was published May 9 in the journal Communications Biology, suggests that elephants are communicating intentionally and that they tailor their greeting depending on what other elephants are doing. For example, when another elephant was already paying attention, elephants were more likely to use visual gestures; otherwise, they were more likely to use touch. 

"For me, it was really exciting to finally do this, to finally understand how they use their bodies to communicate," study lead author Vesta Eleuteri, a graduate student at the University of Vienna, told Live Science. "It's just mind blowing that they do rely on it so much, but it's so overlooked."

Scientists already knew that elephants communicate from up to miles away using deep rumbles that are too low for humans to hear but that their species' massive ears pick up with ease. And their long trunks come with an excellent sense of smell: Elephants can sniff out age, kinship and even social groups — among both elephants and people. Compared with humans, though, elephants' eyesight is relatively poor. 

Related: 'They are very well aware of their agency': Elephant calf burial ritual discovered in India

Previous elephant communication research has tended to focus on sound and smell separately, Eleuteri said, rather than on how those and other senses might work together. 

Eleuteri and her team took a different approach, counting visual gestures — such as ear flapping and trunk reaching — along with vocalizations, touches and scent-related behaviors. They tracked which gestures and sounds occurred together, noting that low rumble noises often accompanied ear flapping — this combination was the most common greeting they documented. The recurring combination suggested the elephants wanted to communicate, Eleuteri said. The elephants also usually looked at each other before gesturing, further reinforcing that idea.