According to Montgomery, octopus escapes from aquariums are common.
"They can squeeze through the tiniest spaces and easily, a 100-pound octopus can squeeze through an opening the size of an orange,” Montgomery said.
The drain pipe in the New Zealand aquarium was about 6 inches wide.
Octopuses can typically squeeze through an opening as small as their mouths, or beaks, as they are the only hard part of their body.
"Their muscles are less like our biceps than our tongues,” Montgomery said, “so they can flow in a way that, even if our muscles were detached from our bones, our muscles could not do."
A slime covering Inky's skin would have prevented it from drying out as he oozed from his tank to the drain that led to his freedom. And the suckers on his tentacles, which octopuses can use to taste food, would have also helped propel him across the floor.
"Each sucker can lift an enormous amount of weight,” Montgomery said.
According to Montgomery, a 3-inch-diameter sucker on a giant Pacific octopus can lift 30 pounds.