The place I stayed on the island of Don Det had a pet monkey. It was said because it had a chain around it's waist and was attached to a barbell. I saw a few in similar circumstances around the islands.

You could see in their eyes that they were lonely and depressed.

The monkey at my place at least had a friend. The family dog. They totally hung out together. It was cool to see.

Unfortunately, the dog could leave whenever it felt like it and the monkey often cried when the dog left.