A truck stops in front of a large, open-air structure. Elephants stand beneath the shade of trees. Several mahouts, the caretakers of the elephants, help unload spiky vines from the truck. We are at the Thai Elephant Conservation Center (TECC) in northern Thailand. These vines will be used to make an herbal medicine for the elephants.

I first came to TECC in 2017, while working as a guide for student groups. I quickly noticed several interesting things. First, TECC had one of the most advanced elephant hospitals in the world. One of the ways they treated elephants was with herbal medicine. As an ethnobotanist, I study the ways that people use, rely on, and relate to plants. So, this caught my attention.

I knew that plant-based medicine and biomedicine (or “Western” medicine) aren’t often found together. Why did TECC use both when caring for their elephants?

Next, I noticed the elephants’ interest in their herbal medicine. I knew that elephants love sweet foods, just like humans. They eat grass, but sugarcane and corn are favorite snacks here.

One of the mahouts told me that the spiky vines are a powerful medicine for people. I took a tiny nibble. It was so bitter that I needed a drink of water.

The elephants, however, happily ate the bitter plants. Why? Did they know it was medicine? A year and a half later, National Geographic Society gave me a grant. I would return to Thailand to try to find the answers.

Elephants have coexisted with people for thousands of years in Thailand. I decided to work with a group of highland people called the Karen. They live in the mountains of northern Thailand and neighboring Myanmar.

The Karen are famous for their knowledge of elephants. How did this relationship begin? One story tells of how the elephant was originally human. Then it lost its humanity and became a helper of humankind.

Elephants played a role in nearly every aspect of life here, similar to horses in other parts of the world. Their knowledge of the forest meant they were the best way to travel long distances over land.

Their incredible strength allowed them to move heavy objects like stones and sacks of rice. Many elephants worked in the logging industry. But as cars and tractors replaced older ways of life, elephants’ usefulness fell.

Logging with elephants is considered more environmentally friendly than using machines. But, centuries of overharvesting threatened remaining forests. In 1989, logging was banned.

Elephants were no longer needed for this type of work. People tried to find new ways to keep these incredible animals. By now, most elephants have been moved to elephant camps for tourists.