Grandpa Red

 How old do hermit crabs get? I looked it up; land hermits can live up to 30 years, but the marine hermits are supposed to live from 2 to 4 years.

I was wondering because the oldest hermit in my tank was looking sad. He came to Campbell River with me; that was 6 years ago. And he was an adult then, a good size for a grainy-hand hermit. He hasn't been growing; he has molted several times, but always goes back to the same old shell. He's an old geezer and the familiar outfit is comfortable.

But now he was looking under the weather. For days he hid under seaweed in a dark corner of the tank. He didn't come out when I offered him food. He hunkered down inside the shell if I moved his seaweed. I worried.

Maybe it was just his time to go.

And then the other morning, I found him under the light, antennae waving happily, and sporting all new light green and blue legs and body. Freshly molted, and doing fine. Hungry.

"Grandpa", in his new suit. And the old shell.

Here he is, just moved into that old shell when it was shiny and new. This was in March of 2018.

"Big Red", I called him then. Now, "Grandpa."

Maybe because he is old the molting took more effort than it does for the youngsters. I can relate to that.

And maybe the age limit was wrong.

And here are the last two tank photos from last year:

A volunteer plumose anemone, Metridium senile, just getting started.

And a carinate dovesnail, showing here his black and white siphon.

These are tiny snails, carnivores, that are obviously breeding in the tank. They eat tiny worms and crustaceans; of these, they find plenty the right size in my tank, hundreds of amphipods. The siphon serves as a sensitive nose, sniffing out suitable prey.

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¿Por cuántos años viven los cangrejos ermitaños. Lo busqué en el web; los ermitaños terrestres pueden vivir hasta los 30, pero los ermitaños marinos apenas viven (dicen) de 2 a 4 años.

Quería saber porque el ermitaño más viejo que vive en mi acuario se veía triste. Vino conmigo cuando llegué a Campbell River hace 6 años. Y era entonces ya un adulto, de un buen tamaño para un ermitaño de manos granosas, Pagurus granosimanus. No ha estado creciendo ya cada que muda, regresa a la misma concha vieja. Es un viejo, y lo acostumbrado ha de sentirse cómodo.

Pero ahora no se veía muy bien. Por varios dias se escondía bajo las algas en una esquina oscura del acuario. No salía cuando le ofrecía comida. Cuando yo movía el alga que lo cubría, se escondía bien adentro de la concha. Me preocupaba.

Tal vez, pensé, que ya era su hora.

Y luego una mañana de esta semana, lo encontré bajo la luz, agitando las antenas alegremente, y llevando todo un traje nuevo; las patas y el cuerpos en azules y verdes claros. Recién mudado, y sintiéndose muy  bien.

Foto #1: "El abuelo" luciendo su traje nuevo. Y su concha vieja.

#2: Aquí está en marzo de 2018, estrenando esa concha cuando era nueva y limpia.

Puede ser que porque ya es viejo, le costaba más cambiarse de ropa. Yo lo entiendo.

Y puede ser que los que daban el límite de vida de estas criaturas se equivocaban.

Extra: aquí están las últimas dos fotos del acuario del año pasado:

#3: Una anémona nuevecita, Metridiuim senile.

#4: Un caracol marino muy pequeño, Alia carinata, mostrando su sifón. Estos caracoles se han establecido en mi acuario. Son carnívoros, comiendo gusanos marinos y crustáceos, de los que hay cientos, los anfípodos, justo del tamaño para estos caracoles. El sifón le sirve como nariz, para oler su presa.

Chance encounter

 Sometimes you're just in the right place at the right time ... Passing my aquarium on the way to start supper, I caught a glimpse of a naked hermit sheltered in the rosy seaweed. Supper forgotten.

A hairy hermit, Pagurus hirsutiusculus, without the protective shell.

Think about crabs. "True" crabs, they call them; the crabs you see scuttling sideways on the shore. They have a soft body encased in a hinged hard exoskeleton, the carapace on top, the abdomen beneath, sort of like a clamshell. When they grow and need to molt, they open this shell and back out, leaving the perfectly formed crab shape behind.

Hermit crabs don't have the hard covering for the abdomen, which is much larger than that of the "trues". The upper body is encased in a hard casing, but the abdomen hangs out, looking like a sausage, soft and juicy, a tempting taste treat for fish and crabs and shorebirds. So they wear a borrowed shell for protection.

Freshly-molted hermit, showing the upper carapace, two tiny grasping legs, and the front end of the soft abdomen.

As a hermit (or crab) grows, the exoskeleton becomes a tight fit. It doesn't grow with the critter inside, so there comes a moment when he pulls himrself free and backs out, pulling the eyes down out of the eyestalks, the legs and pincers out of their chitinous coating; even the antennas are retracted, leaving the antenna shape behind, attached to the old body shell.

Dried abandoned hairy hermit molt. (2010)

And now the hermit is in danger. He's soft all over; not only that dangling abdomen looks good to eat.  So he heads up, away from the always hungry crabs beneath. He climbs a blade of eelgrass, or, as here, drifts on the seaweed.

Like a butterfly just out of the chrysalis, who rests in the sunlight, slowly unfolding and stretching out her wings until they are stiff enough to fly, the hermit waits in his safe place. He takes in water and swells out before the new carapace hardens, he waits until he feels strong enough to brave the dangers below in his search for a new shell to enclose that vulnerable abdomen.

His colours are pale at this stage, and free of algae and grunge.

My bad: trying to get a clear photo, I moved the seaweed and he fell off, down to the sand. Down where a crab lurked. I quickly rescued him, and set him to rest safely in a small bowl of water, then searched the tank for shells that looked about the right size for him. (Normally, he would do this when he was ready and able to run from the crab.)

And he rested only a few minutes, then chose a shell and moved in.

This one looks about right. Body hardened, abdomen protected. Ready to roll!

I gave him some time to settle in, then returned him and the other shells to the tank. And he ran off, happily, to look for food. Needed a pick-me-up after all that work!

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A veces el azar te sitúa en el preciso momento y lugar ... Iba a la cocina para preparar la cena, pero pasé el acuario y vi un ermitaño desnudo. Se me olvidó lo de la cena.

Foto #1: El ermitaño, un ermitaño "peludo", Pagurus hirsutiusculus, escondido entre las algas marinas.

Considera los cangrejos. Un cangrejo "verdadero", como les llaman: los cangrejos que ves corriendo lateralmente en la playa. Tienen un cuerpo blando, encerrado dentro de un exoesqueleto quitinoso articulado, el caparazón arriba, el abdomen abajo, algo así como la concha de una almeja. Cuando crecen y les llega la necesidad de mudar, abren este exoesqueleto y se retiran, despegándose hacia atrás, dejando en la playa la forma perfecta del cangrejo ausente.

Los cangrejos ermitaños no tienen la corteza dura para el abdomen, y éste es mucho más grande que el de los cangrejos "verdaderos". El cuerpo anterior está cubierto de un caparazón, pero el abdomen se cuelga sin protección. Parece algo así como un chorizo, y así lo ven los cangrejos, los peces, hasta los pájaros costeros, un chorizo delicioso. Por lo tanto, los ermitaños esconden ese abdomen dentro de una concha de caracol prestada.

Foto: un ermitaño recién mudado, mostrando el caparazón, dos patitas que sirven para fijarse a la concha prestada, y la parte anterior del abdomen.

Cuando crece un ermitaño, o por cierto, un cangrejo, este exoesqueleto llega a quedarle chico, incómodo. No crece con el animalito por dentro, y viene el momento cuando se separa buscando la libertad, retirando los ojos de los pedúnculos oculares, las patas y las pinzas de sus formas, hasta las antenas de su corteza, dejando la forma de la antena todavía haciendo parte del viejo exoesqueleto.

Foto: una muda de un ermitaño P. hirsutiusculus, resecada.

Y ahora está en una situación peligrosa. Todo el cuerpo recién mudado es blando; ahora parece buen alimento para los cangrejos y otros depredadores. El ermitaño se escapa, subiendo por las hierbas o escondiéndose entre las algas donde no le alcancen los cangrejos.

Como una mariposa recién eclosionada de su crisálida descansa en el sol, estirando y desdoblando las alas, esperando a que estén suficientemente rígidas para poder volar, el ermitaño espera en su lugar protegido. Toma agua, y se hincha antes de que su piel se vuelva dura, un nuevo exoesqueleto, espera hasta que se siente capaz de arriesgarse allá abajo, donde tiene que buscarse una nueva concha.

Foto: un ermitaño recién mudado tiene los colores claros, las patas limpias, sin algas.

Y fue culpa mia; tratando de sacar una foto, arrimé el alga, y el ermitaño se cayó al suelo, donde peligraba su vida por la presencia de un cangrejo. Lo rescaté de prisa, y le puse en un platito con agua donde nada de amenazaba. Luego le busqué una variedad de conchas más o menos de un tamaño que le quedaría. (Normalmente, el mismo haría esto cuando se sentía con fuerzas.) 

Esperó unos cuantos minutos, y luego escogió una concha y se insertó en ello.

Foto: el ermitaño en el plato, con su nueva concha.

Le dejé un tiempecito para descansar, y luego lo regresé al tanque. Y se fue muy contento a buscar algo que comer. Después de todo ese trámite, tenía hambre.

I call him Joseph

Our local hermit crabs, the Hairies, Pagurus hirsutiusculus, are usually a drab greenish-brownish-greyish mud colour. It's a mask; they're wearing a coating of algae, mud, leftover grunge, and sometimes a few barnacles. Underneath all that, they're a pale green, with blue knees and white patches on the legs. The body, of course, is hidden by the borrowed shell.

When they're freshly molted, and haven't had a chance to muddy themselves up yet, the true colours shine through. I caught one a few minutes after a molt, hanging out on the seaweed right in front of the wall, without a shell, showing off his coat of many colours.

Red, orange, yellow, green, blue, indigo, violet; all the colours of the rainbow.

The photo is fuzzy; the seaweed is swaying, the glass wall algae-coated. But the colours shine through.

Hairy hermit, as found on the shore, in his normal coating of mud and algae.

(Title from the Biblical story of Joseph.)

High flyer

The ocean surface temperature along the east coast of Vancouver Island varies from about 6.5 degrees Celsius in February to a maximum of approximately 13.5 in August, our hottest month. (That's 45 Fahrenheit to 55 F.) My aquarium sits in a warmish room, with an average temperature of 20 to 21 degrees Celsius in the winter, more in summer. It's too hot for my intertidal invertebrates here, even in midwinter.

I keep everybody happy and healthy by adding ice to the tank. I freeze tank water in yogurt containers that have never seen detergent (which will poison some of the animals) and exchange them for the ones floating at the top of the tank several times a day. It's not pretty, but it works.

This morning, when I went to change the ice, I found a naked hermit riding the yogurt container. How he got up there, I don't know; he can't swim.

Hairy hermit, freshly molted.

When hermit crabs molt, they have to leave their shell. Often it won't fit any more when the molt is finished; all their growing happens in those few minutes between a molt and the hardening of their new skin.

They're vulnerable in this situation. Crabs aim for that juicy, curly abdomen. Fish, too. Luckily, there are no fish in this tank, but there's one big, starving (to hear her tell it) green shore crab. So the hermits head for the highest spot they can find to wait out the growing time. This one somehow found his way onto the iceberg.

It was a good choice. He'd already been damaged; he's missing his main defensive weapon, the large pincer on his right side. He uses the smaller one on the left to manipulate his food.

To replace the ice, then, I removed the yogurt container carefully, hermit and all. I put him into a bowl with a few empty shells for him to choose between whenever he was ready. 5 minutes later, he was dressed and rarin' to go. He had probably been waiting on the floating container for some time, not knowing how to get off without risking dropping into the waiting crab pincers.

With a good shell (according to him: he chose a broken one, well worn and covered with algae. He knows what feels best.) he went safely back into the tank.

(Look back at the photo. Look at the first foot on the upper left. It's not usually apparent that the legs are basically transparent, but here you can see the design on the yogurt container showing through.)