All the houses in my 1980s-built neighborhood were painted in just a few dull repetitive colors. They are essentially all the same.
But I dream of living in a neighborhood with a full spectrum of vibrant colors in every combination. So, I did something about it by painting my house using the color palette of our local blue topsnail (Calliostoma ligatum).
The colorful “home” of the full-grown blue topsnail is a conical shell about an inch wide and high, with a pointy tip and round opening. Its spirals are sculpted with thin longitudinal ridges that alternate light and dark. The colors may include purple, blue, orange, pink, red and brown. And in areas where the outer shell layer is worn away, iridescent blue shines through.
These snails typically live on and around kelp in the rocky intertidal zone. So, their shells are most likely to wash up on rocky beaches. And the best way to see a live one is in a rocky tide pool on a very low tide. Hermit crabs also use old topsnail shells for homes, so look for them staggering around in the tide pools, too. In fact, the shells used by the hermit crabs are more likely to be completely worn down to the shiny blue inner layer.
Because they live in high-energy, rocky areas, topsnail shells are prone to cracking. So, like most snails, they are capable of repairing a crack by sealing it from the inside with a fresh layer of excreted shell material. The thin, high-contrast ridges can make it obvious where a snail has repaired a crack — looks like a fault line in banded sedimentary rock.
The topsnails themselves eat the algae they live on, plus they consume the other things that settle on the algae and surrounding rocks, such as encrusting bryozoans and even random detritus. Their diet is fairly wide-ranging without them having to actively seek out the variety. They just rasp along with their tongues and get whatever is in the way.
The topsnail’s muscular body has a dark brown upper surface that turns speckly and becomes cream to orange under its foot. And it has a row of usually five thin tentacles that stick out from each side and detect chemicals given off by predatory sea stars.
The blue topsnail is known for “running” from these predators. The sea stars are also very slow, so it’s not a cheetahs-chasing-gazelles scenario. And as the predator gets close, the snail can fight back by “biting” the predators with its sharp, rasping tongue. In the world of the ultra-slow, it makes for an exciting chase.
Like many other snails, the blue topsnail possesses an operculum, which is a little trapdoor-like disc that closes to seal the snail inside its shell. This functions mainly to keep it from drying out at low tide but may also protect the snail from predators if they can’t run away. The topsnail’s operculum develops concentric rings as it grows, and it is made of a semi-translucent and flexible protein material. (The door of my house is painted to look like an operculum.)
When it’s finally time to repaint, I hope neighbors feel comfortable showing their colors. But hopefully some people choose to keep their houses in muted colors to preserve an honest diversity because the equity of these houses is valid, and their inclusion is essential.
I hope the neighbors are inspired by or ignore my blue topsnail-themed house. But if they are anti-snail colors and come around with complaints, I will introduce them to the sharp rasping tongue behind the operculum.
Biologist Mike Kelly (he/him) also writes science-based satire as M. Sid Kelly. It’s available at Eureka Books or everywhere e-books are sold.
This article appears in Restaurant Week 2025.