Strombus alatus behavior?

[Ninong]

Hi Dr. Ron,

I have two Strombus alatus in my 120-gal reeftank with DSB. Both were acquired about nine months ago from Reeftopia in the Florida keys. Both are collected specimens and were about 1.75" long when I got them. I estimate that they are approximately 2.25" long today.

During the first few months, it was quite common for one or both of them to bury themselves in the sand for several hours to several days at a time, but they spent at least 90% of their time cruising the sand bed. Then four or five months ago one of them disappeared. At first I figured it had perished somewhere in the tank out of sight until one day I spotted one of its eyes poking out of the sand bed while the other conch was in plain site at the other side of the tank. That's when I knew it was still alive. I witnessed it moving it's eyestalk around for several minutes before withdrawing it beneath the sand. I left it undisturbed, satisfied that it was still alive and probably just "resting."

A few days ago I got the urge to see if it was still in the same spot, so I poked my finger under the sand and sure enough it was still there. I lifted it out of the sand and brought it closer to the surface for a better inspection. At first I though I had an empty conch shell but then I saw something moving inside -- deep inside -- so I placed in back on the sand bed. Within a couple of minutes it began to move around grazing on the surface of the sand bed just as it did before it went "underground" some four or five months ago. It happened to come across the other S. alatus and they sort of greeted each other, or at least they bumped up against each other several times before going on their separate ways. Then two days after I exhumed it, it went back under the sand in the exact same spot as before. It has been there for the past two or three days and it is well beneath the surface of the sand bed without it's proboscis or eyestalks protruding above the sand.

Is this behavior normal and, if so, what is its purpose?

Thanks,

:)

[rshimek]

Hi,

My alatus did much the same thing. I presume the behavior is normal. I don't have a clue as to why they do it. It is possible that they may come out of the sand at night and home to the same burial site during the light, but I really don't know. Sorry. :(

[Ninong]

Ron,

Thanks for your insight. Actually I can attest to the fact that this particular specimen does not come out at night and has remained in the exact same spot for at least four months.

There are two different behaviors that I have observed:
Periodic burying just beneath the sand bed surface with the proboscis and one or both eyestalks above the surface. These episodes last anywhere from a few hours to a few days.

Deeper burying with the entire shell at least 1/2" beneath the surface and the animal fully retracted within the shell. In the one instance that I have observed, the animal did stick one eyestalk above the surface for perhaps an hour before retracting it. The proboscis remained beneath the surface and the shell remained well beneath the surface. This episode has lasted approximately five months so far.

:)

[NicoleC]

I have what appears to be a conch of some sort that has similar behavior. I think I got it as a "hermit crab," or else it was a hitchhiker with the LR. It will come out and clean like mad for a couple of weeks, then bury itself for a month or months. Just when I think it must be dead, it pops up.

It is quite good at cleaning up corals very gently (no, it's not eating them, I've watched carefully!) and even eats hair algae when I have it. I wonder if it buries itself to hibernate until there is more food to eat?

[rshimek]

Hi,

All we have is guesses at this point. I have seen no description of this type of behavior in the scientific literature - but then again, :D, I haven't looked for it too much, either.