Science Daily reports on simple organisms called “comb jellies” (a.k.a. “ctenophores”) that have a weird way to overcome physical trauma. If two or more of them are seriously injured, to the point where they each lose part of their bodies, they’re able to fuse two different partial bodies together. In other words, two individuals merge to form one new whole individual:
“Our findings suggest that ctenophores may lack a system for allorecognition, which is the ability to distinguish between self and others,” says Kei Jokura of the University of Exeter, UK, and National Institutes of Natural Sciences in Okazaki, Japan. “Additionally, the data imply that two separate individuals can rapidly merge their nervous systems and share action potentials.”
Jokura and colleagues made the observation after keeping a population of the comb jellies in a seawater tank in the lab. They noticed an unusually large individual that seemed to have two backends and two sensory structures known as apical organs instead of one. They wondered if this unusual individual arose from the fusion of two injured jellies.
To find out, they removed partial lobes from other individuals and placed them close together in pairs. It turned out that, 9 out of 10 times, it worked. The injured individuals became one, surviving for at least 3 weeks.
Further study showed that after a single night, the two original individuals seamlessly became one with no apparent separation between them.
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You can read more of the animal-fusing research here, in Current Biology.