Week of July 23, 2023 – July 29, 2023

Bridget Jones staff member and Environmental Educator

by Bridget Jones, Environmental Educator

As I’ve been walking in the woods this summer, a particular kind of creature has been catching my eye. These creatures are small, grow from soil or decaying wood, and come in a fascinating array of shapes and colors: bumpy bright red globs, smooth pink beads, clusters of brown threads, bright yellow networks. While they appear similar to fungi or plants, these creatures don’t fit into either category. They’re not animals, either. They are slime molds, bizarre and underappreciated gems of the forest.

If slime molds aren’t animals, plants, or fungi, what are they? Categorized in the kingdom Protista, slime molds are actually single-celled amoebas. As single cells, slime molds move through soil, searching for bacteria to consume. However, when many single-celled slime molds come together, something incredible happens. The cells combine to form a new organism that moves together, oozing slowly over forest surfaces. The collective slime mold can achieve things that single cells cannot, like transform into structures that create spores, helping the slime mold reproduce. By joining together, slime molds turn from invisible cells to the brightly colored, uniquely shaped forms that we see in the woods.

The deeper you look into the world of slime mold, the stranger it gets. Slime molds have been found to be adept problem solvers. One study found that slime molds can navigate through a maze to a food source on the other side. By reaching out tendrils and investigating different paths, the slime mold can identify, remember, and eliminate dead ends to find the solution. In another study, scientists placed slime mold on replicas of several countries such as Japan, Canada, and England, leaving food sources where urban centers would be. In seeking out the food sources, the slime mold chose the most efficient route between urban centers, recreating the paths of existing highway and railroad networks. Incredibly, slime mold is able to do all of this without a brain.

These amazing creatures, with their strange biology, unexpected intelligence, and beautiful appearance, hold an important place in the forest ecosystem. Like fungi, slime molds are decomposers, breaking down organic matter and returning nutrients to the soil. They are also eaten by wildlife, like slugs and beetles. Keep an eye out for these strange amoebas next time you walk in the woods, and remember that there is much more to them than what you see on the surface.

If you’d like to learn more about slime mold, check out this article: https://www.scientificamerican.com/article/brainless-slime-molds/