I walked a sandy beach recently and ran across what appeared to be a little gray inner tube. What the heck? Then I found a few shells with perfectly rounded holes in them, like someone with a countersink bit had spent time trying it out. Moon snails are responsible for both. These big predatory mollusks can be 7” across with a large foot it uses to plow along searching for clams. Finding a target, the moon snail uses its foot to surround the victim, then a toothed ‘tongue’ or radula drills a perfect hole to get at the inhabitant. The ‘foot’ is actually the snail’s trap door and transportation all rolled into one.
This snail puts its eggs in a mucus glob that is then molded by the foot into a round ‘collar’. This 6” inner tube-shaped thing has the eggs hiding beneath, but it will never be a complete circle shape because the snail starts laying its eggs at one side and finishes without joining the ends. Keep your eyes open for this stuff on your next anchorage beach walk.
Larry paints and blogs about wild places at larryeifert.com. His work can be seen in many national parks across America.