• Question from:Charles Kelly

I live in ORange County California and while hiking I found this bone. I have no idea what it might be. Could be a bird or mammal. Almost certainly not reptile or amphibian. I found it in a dry creek bed / wash with seemingly no other bones or bone fragments. I thought it could be a scapula or pelvis?

This is the location I found it: 33°48'03.58" N 117°45'40.18" W

Thanks for any help. I am taking a naturalist class and this would be very helpful.

Post's pictures

IMAG0459.jpg, 785.79 kb, 3264 x 1952

IMAG0460.jpg, 796.41 kb, 3264 x 1952

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  • At home in Ruardean, Gloucestershire, England
  • Posts: 942

How interesting!

I don't know what the bone is; but the very delicate structures visible in the top part of your first photo look very much like what you get when the bones of birds are invaded by airways -- you can see some nice examples in this back vertebra:
http://courses.washington.edu/chordate/ … caudal.jpg

Among living animals, only birds do this to bones outside the skull, and since your bone doesn't look like a skull-part, my guess is that you have a bird bone, perhaps part of the sternum.

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  • Horniman Museum, London, UK
  • Posts: 1,105

I'm pretty certain this is the opercular bone of a fish. This is the bony flap that covers and protects the gills. I'm afraid I'm not familiar enough with fish anatomy to identify it to species level though.

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  • University of Bristol
  • Posts: 4,230

Charles then posted again:


This site is great!  Thanks for the feedback on my previous photo of the mystery bone.  I didn't see a way to reply with a thank you so I'm going this route.

Interesting responses.  The name for the habitat of the area where the bone was found is known as coastal sage scrub / chapparal.  It's a semi-arid / Mediterranean climate, with very little annual rain fall.  There are little to no permanent streams, no lakes and no rivers.  The creek bed / wash where the bone was found only has water when it rains.  There are no fish anywhere nearby except about 15+ miles to the West in the Pacifica Ocean.  I suppose that it is possible that someone brought a fish up into the hills and dumpbed it or maybe a bird carried one up there.  But, I was looking at a lot of bird skeleton images and I think it looks somewhat like a "pelvic girdle".  Possibly from a pigeon or a mourning dove that may have been preyed upon by a coyote, bobcat or hawk.

Thanks again!

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  • Horniman Museum, London, UK
  • Posts: 1,105

I would say that this is not the pelvic girdle of any vertebrate I've ever seen. I'd stick to the fish operculum identification - it may have been transported and deposited by ephemeral streams, or by birds of prey. You'd be amazed at how far skeletal material can be moved from the place where an animal dies!