Remember Inky, who fled from New Zealand’s national aquarium? The cephalopods can Houdini their way out of tanks and off boats by squeezing through narrow slits and incredibly tiny holes. Now researchers know exactly how some octopuses pull it off.
These masterful getaways involve a consistent, step-by-step game plan, researchers report November 5 in the Journal of Experimental Biology. Octopuses are mostly squishy muscle, allowing them to shape-shift, though they do have some rigid body parts. Not many scientists have studied how these animals squirm through small openings, says Robyn Crook, an evolutionary biologist at San Francisco State University who was not involved in the research.
The animals use that skill to find hidden food and to avoid becoming food themselves. Kuba and his colleagues observed how three common octopuses (Octopus vulgaris) and four Mayan octopuses (Octopus maya) approached small holes. For each individual, the team measured the distance between the octopus’s eyes as an indicator of the size of their most rigid cartilage around their brain.
Then the researchers designed acrylic boxes with holes that were slightly smaller or larger than that eye-to-eye measurement. They plopped the octopuses inside and watched what happened. Octopuses have slightly different escape how-tos, depending on the size of the hole they are squeezing through.
Here, a common octopus (Octopus vulgaris) wriggles through a space just a little bit bigger than their most rigid body parts. It takes just three steps for the octopus to free itself from the acrylic box. Common octopuses used one of two escape strategies depending on the hole’s size.
When the hole was wider than the distance between their eyes, the octopuses pushed themselves through it in three steps. First, they snuck one or two arms through the hole and then threaded a couple more arms through. Finally, they used the arms that they had already snaked through the hole to push against the box and yank their head and the rest of their arms through in one fell swoop.
Extract — continue reading at the source.
