As they delve into the topic, researchers reveals their observations and findings. It's pretty amazing. The programme/podcast is well worth a listen:
Do animals use medicine? (March 2021) https://www.bbc.co.uk/programmes/w3cszv77
> Presenter Anand Jagatia speaks with the primate researcher who stumbled across a chimp chewing on a bitter leaf 35 years ago, Professor Mike Huffman, whose observations opened up a whole new field of research. We discover why plants contain the medicinal compounds they do, and how butterflies with brains no bigger than a pin-head are still able to select and use medicine to protect their young.
> We think of medicine as a human invention - but it turns out that we’ve learnt a lot of what we know from copying the birds, bugs and beasts.