Faced with an incoming predator, most snails don't really have a lot of options other than to retreat into their shells. But scientists have discovered that members of a certain species won't take such provocations lying down, instead aggressively swinging their shells from side to side to gain the upper hand on an assailant.
The species in question hail from Russia and Japan, and are known as Karaftohelix selskii and Karaftohelix (Ezohelix) gainesi, respectively. Scientists at Japan's Hokkaido University and Tohoku University teamed up with researchers at the Russian Academy of Sciences to study how the two snails behave when under threat from a carabid beetle, and were surprised to find that they were capable of launching some pretty brutal counterattacks.
The scientists observed how once the snails sensed the carabid beetle in the vicinity, they would begin to swing their shells about to clear the area and knock the beetle down. They say that this appears to be a highly unique trait, with other closely related snail species instead hiding away inside the shell until the attacker stands down.
"The difference in their defensive behaviors is also reflected in their shell morphology, indicating that their behaviors and shell shapes are interrelated to optimize the preferred defense strategy," says Yuta Morii, the study's lead author.
What's more, the researchers analyzed the DNA sequences of the snails and found that these behaviors evolved independently of one another. That these traits evolved in parallel on different continents, the researchers say, highlights the significance of predator-prey relations in shaping the evolution of organisms.
The research was published in the journal Scientific Reports, and you can see a Ezohelix gainesi snail and carabid beetle go at it in the video below.
Source: Hokkaido University / Video: Morii Y. et al., Scientific Reports, November 11, 2016