The low tide allowed easy access to groups of common periwinkles. The perwinkles sampled were found on hard rock surfaces in water approximately two to three feet deep and 20-40 feet into the water.
Two periwinkles were selected for a experiments. Both were healthy and alive. The first was to examine how a perwinkle would gain a footing if was left on it's back. The perwinkle extended itself slowly using the weight of it's body to cause the shell to roll over at which point the perwinkle was able to regain adhesion to a solid surface in a few seconds.