Watch Slime Molds Creep and Crawl Like Alien Slugs - Atlas Obscura
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Watch Slime Molds Creep and Crawl Like Alien Slugs

A Princeton biologist’s clips look like footage taken from a 1950s science-fiction movie.

On the decaying remains of plants and trees, slime molds crawl, congeal, and bud in an alien-like manner. This flickering black-and-white footage makes these simple, single-celled organisms look even more like gooey slugs or monstrous creatures featured in a 1950s sci-fi flick.

Princeton biologist John Bonner (named the “patriarch of the slime mold community” by Science magazine) has filmed and studied slime molds since 1940 when he was an undergraduate at Harvard. His footage captures these simple organisms’ curious collective behaviors.

Slime molds are “no more than a bag of amoebae encased in a thin slime sheath,” Bonner once said. “Yet they manage to have various behaviors that are equal to those of animals who possess muscles and nerves with ganglia—that is, simple brains.”

Cellular slime molds (the group of slime molds Bonner studies in his lab) assist in the decomposition process. They are usually found as individual cells, or protists, in soil, mulch, leaf mold, cow dung, and even air conditioners. They can grow at a rapid rate, the cell population doubling in just a few hours. When food is scarce, the cells secrete chemicals and quickly lump into a creeping, large glob—thousands of individual cells working together to move and gobble up a new source of food.

At the 30-second mark, you can see this behavior as cells of a slime mold crawl back together like inch-worms after being separated.

They also create chains in a conga line-like fashion in nutrient poor environments. It grows a stalk with a nipple-shaped bud filled with living spores, that pop out of the soil and are dispersed by insects.

Bonner believes this is a self-sacrificing behavior because the cells that make up the growing stalk die. 

Slime molds hold no known harms to humans. Even though Bonner’s clips of the crawling slug-shaped slime molds may make some shiver, he appreciates the sophisticated survival tactics the organism has evolved.

I stare at slime molds—and they’re beautiful.”

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