4 Woolly Bear Caterpillars
Some animals may seem to lack the brainpower required to engage in self-medicating behavior. However, even the smallest creatures can improve their own health, including insects. One example was observed in a study of woolly bear caterpillars.
Most animals seem to know exactly what is available in their environment to improve their health. The caterpillars in the study foraged for plants containing toxins that kill parasitic tachinid flies. These small insects serve as an example that almost any animal can self-medicate.