Monday, June 6, 2011

The Very Hungry Nudibranch

Last Thursday, guests and staff were treated to a rare sighting of the Puget Sound Tide Pool model’s one and only shaggy mouse nudibranch (Aeolidia papillosa). This marine slug grazes on the tentacles of sea anemones. Having eaten the tentacles, it stores their stinging cells in its own body, rendering it toxic to predators. The shaggy looking growths on its back, which earned it its name, actually contain these stinging cells.

An unexpected stowaway from our most recent tide pooling expedition, the shaggy mouse is often hard to find. Unlike many home loving tide pool animals, it does not predictably return to a few favorite haunts. Since it is also small, flexible, and sandy in color, it tends to disappear for days or weeks only to suddenly appear in a new part of the exhibit.

In Pacific Science Center’s Life Sciences department, we must constantly remind ourselves not to anthropomorphize. Sometimes are easier than others. As the fluffy little nudibranch crawled between the arms of a purple sea star, it was all we could do not to think the star was petting it.


  1. How long will you keep it in the tide pools?

  2. From Animal Care Lead, Brianna Todd:

    "Nudey" the nudibranch will be living in the tide pool for the rest of its life. We are required by the Department of Fish and Wildlife to keep all of our animals forever. If we were to reintroduce a marine animal back into the wild we could potentially be adding diseases or nonnative species with it, something we all want to avoid. Thanks for the question!

  3. For those who are worried about our anemones, there is a bit of good news. Because Nudey the nudibranch only eats the tentacles, and because there are an abundance of anemones and only one nudibranch, it appears that he/she is able to harvest them sustainably, allowing time between feedings for the tentacles to grow back.