What is this on my hammer?

[nandi]

Hi, does anyone know what this is on my wall hammer? It seems to moving. Like its tightening (closing).
Thanks in advance.

 

[Dburr1014]

Not sure what part your looking at.
Can you circle what your questioning?

 

[nandi]

Not sure what part your looking at.
Can you circle what your questioning?

Hi, this bit. Thanks.

 

[nandi]

Video

 

[kchristensen8064]

I'm guessing a bivalve of some sort. I've had them as hitchhikers and they are pretty neat to watch, if it is a bivalve it should be harmless, may affect how your hammer grows but just because of its location.

 

[Dburr1014]

I'm guessing a bivalve of some sort. I've had them as hitchhikers and they are pretty neat to watch, if it is a bivalve it should be harmless, may affect how your hammer grows but just because of its location.

That what I was thinking also.

@ISpeakForTheSeas have you any idea?

 

[ISpeakForTheSeas]

That what I was thinking also.

@ISpeakForTheSeas have you any idea?

Definitely a couple of bivalves there - my first thought would be either oysters or mussels of some variety, but I don't know for sure there. Regardless, they're harmless filter-feeders.

OP, you want to try for a more specific ID, pics of the mouth and hinge of the critters, pics showing both halves of the shells from the side, and a description of how they're stuck onto the hammer there (cemented on, held on byssal threads, etc.) would all be helpful - no guarantees on a more specific ID at this point, though, as I'm still learning bivalve ID and a lot of the ID characteristics that I've found used are for things inside the shell (so not very useful with a live bivalve).