Lasting feelings of pain or anxiety after an injury may seem perplexing, but they serve an evolutionary purpose, research suggests.
Squid that behave more vigilantly after even a minor injury are more likely to survive than their more brazen counterparts, a new study reveals. The findings suggest that persistent pain may be more useful than once thought, according to the study published today (May 8) in the journal Current Biology.
This study provides the first direct evidence to suggest that animals developed heightened sensitivity- which promotes pain in some animals - in response to natural selection, particularly to avoid predators, said study researcher Edgar Walters, a biologist at the University of Texas Medical School at Houston. [5 Surprising Facts About Pain]
No pain, no gain To study the evolution of lasting pain, Walters and his team studied how squid interact with their predators, black sea bass.
When squid feel threatened, they perform a step-by-step series of defensive behaviors, even if the predator is far away, the researchers said. The scientists observed squid and black sea bass swimming in laboratory tanks, and compared how healthy and injured squid responded to different levels of perceived danger.