Spotted hyenas sound different and can identify friend from foe

Hyenas at the Maasai Mara. [Wilberforce Okwiri, Standard]

On quiet nights across large swaths of the African bush, you may hear a series of whooping calls in the distance. This unique sound is the long-distance vocalisation used by spotted hyenas (Crocuta crocuta) to communicate with each other.

For hyenas, it's advantageous to know who is calling before deciding to respond. They don't treat every member of their group the same - and the caller could even be an intruder in their territory.