"With no brains or nerve cells, single-cellular microorganisms are often regarded to be simple, primitive beings with few capabilities. However, a new Harvard University study suggests that protozoans, like Stentor roeseli, have the smarts to make "complex" decisions when confronted with unpleasant situations.
The trumpet-shaped creature, found worldwide in freshwater ponds, lakes, rivers, and ditches, attaches itself to a firm surface such as algae or submerged waste. It then uses its large mouth-like opening, which contains thousands of tiny hairs called cilia, to suck in food.
The simple creature's decision-making prowess was first observed in 1906 by American zoologist Herbert Jennings. The researcher noted that when exposed to an environmental irritant, in this case carmine powder, the S. roeselii swayed away as though hoping it would pass and things would return to normal. If that failed to work, the microorganism tried several other clever tricks, such as reversing its direction or contracting, before finally detaching from its anchor and floating away in search of a more tranquil location. Unfortunately, Jennings' findings, which could not be replicated by other scientists, were met with skepticism and soon dismissed."
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