Have House…Will Travel

by Supervising Ranger Jim Serpa

While I was contemplating what to write about in this newsletter I was inspired by two recent episodes in my life. One was the recent departure of long time ranger Brad Keitzman. Brad loaded up his house and moved to Tennessee. Nashville, that is, Dollyworld, country music stars. The other incident was the visiting of my two nieces, Jessica and Jamie, from Arizona. My house normally seems quite spacious for my wife Debbie, my boy Noa, my dog Xena and me. Add a couple of teenage girls and the house takes on a much different feel. In other words, it was small. Sorry girls!

If only we were hermit crabs we could scrounge around for a suitable abode, crawl out and swap homes. No looky loos, no real estate agents, no points, no closing costs. Contrary to their names, hermit crabs are not true crabs. They are crustaceans like the true crabs, but belong to a group called Anomura, which number worldwide about 1300 species. These decapods (ten legged animals) range from our friend the puny hermit crab to the humongous Alaskan king crab.

Hermits differ from most crabs, true or not, because of the lack of any hard protective shell to cover their abdomen. That is why they need to use the discarded shell of some long dead snail as their home. Vicki, our interpreter, really likes that aspect of the hermit's lifestyle. Without this shell their soft body parts would be easy to attack by predators. All this being said, the hermit crab is a crustacean and needs to molt the hard shell, they do have when the time is right. We often find their molt in our tide pool display, having slipped out of their shell and now, too small, carapace, and quickly scampered back into their shell. The molt looks like a dead hermit crab to many but if you look closely you will see that it lacks an abdomen indicating it is just a molt.

Many hermits have one claw that is substantially larger than the other. This serves at least two purposes. The first is that it often uses this large claw to block the entrance to its shell for protection. The second is that having two sized claws allows the hermit crab to feed on different sized food. A good deal for the hermit since they are opportunistic feeders, dining on dredged up sediments, dead and decaying plants and animals, and even filter feeding. Most of the hermit crabs in this area are members of the genus Pagurus. All Paguridae hermits are right handed (clawed). Different species actually prefer different shells. Some prefer the black turban snail shell, while others prefer the kellets whelk and still others take a liking to the moon snail shell. There are even those discerning hermits that wouldn't be seen without a shell covered in sponge, hydroids or anemones. They use this covering to both help camouflage themselves and for protection from predators because of the stinging cells of the hydroid and anemones.

The most common hermit crab in our tide pools is the Blueband Hermit. They are identified by a distinct blue stripe on their legs. These are the ones that can be seen scurrying around at low tide usually in black or checkered turban snail shells.

The best time to see Bluebands is in the early morning and late afternoon at low tide. They give birth nearly year round in Southern California. Mating takes place when the males grabs the females shell. The big brute carries the female around with him until the time seems just right. Actual mating takes less than one second. The eggs hatch and float around for about a month then settle down on the bottom of the ocean to start their life as teeny tiny hermit crabs.

This brings me to my final topic. These are also the same hermits we see in our visitors' brightly colored plastic pails. Most people don't mean to harm the hermits but after sitting in the pails for hours at a time, while the temperature of the water skyrockets and the oxygen level plummets, these comical animals often don't make back into the wild. Of course that's not to mention the people who take the hermit crabs home with them. These poor souls die and start stinking to high heaven -- the hermit crab, that is, not the park visitor. The shells are then discarded into the nearest trashcan. This is bad enough, but what makes it even worse is that the hermits' shell will now never be put back into use by other hermit crabs. You see, the hermit crab is the ultimate recycler. When you get right down to it, the most important aspect of a new hermits shell is that they have room to grow. When people take seashells home or even whole hermit crabs, those shells now become a scarce commodity for the hermit crab. That becomes the limiting factor for their population. Without a shell to swap the number of hermit crabs decreases in an area. We have seen that happen up and down the California coast.