For gelatinous blobs, sea anemones have a lot of personality. Animals are considered to have personalities when individuals show consistent differences in behavior across time or situations. In a paper published online this month in PLoS ONE, researchers showed that over the course of 3 weeks, individual wild beadlet anemones, Actinia equina, were remarkably reliable in how long they kept their tentacles withdrawn after being surprised by squirts of water. Each anemone maintained its "startle response" for anywhere from about 3 to 20 minutes, but the duration was roughly the same in response to every squirt. And the trend held regardless of the temperature in the anemones' tide pool homes, a variable that can affect behavior. In fact, the anemones showed more consistency than most other animals tested for personality in the wild. A variety of vertebrates and a handful of invertebrates, including octopuses and spiders—even a bacterium—are members of the personality club, but the researchers say sea anemones set a new bar as the animal with the simplest nervous system.
See more ScienceShots.