Erich von Holst was a German scientist who did important work in understanding animal behavior. He studied how animals interact with each other and their environment. He did experiments to understand how animals react to things like food and shelter, as well as how they make decisions. He also studied how learning and memory work in animals. By understanding these things, he was able to come up with new ways to help animals, such as using food rewards to encourage them to behave differently. Erich von Holst's work is still important today, and it is used by animal experts in lots of different places.