another bone identification question

Hello,

Here is another bone that someone in my family found.

Anybody have any guesses as to what it is from?

The calcium appears to have washed out of the honeycomb like structure of the bone. Worst case of Osteoporosis I ever saw. Does it appear to be bone yet or has it fossilized meaning that other minerals have replaced the calcium in the bone honeycombs (I call them honeycombs because I don't remember their name)

I think that it is bone, as the overall density is fairly low. The weight of the bone is about 10-20 pounds if I recall, unfortunately I was not clever enough to put it on a scale. Would not a fossilized bone weigh a lot more?

Is there a rule of thumb for how long bones can last without completely deteriorating? While I'm sure that it is completely dependent on the environment, is there a good upper bound?

Where abouts did they find it? field, woods, hills, or lakeshore? what part of the country?

I`d say it is definitely a bone from a very massive animal. I don`t recognise the bones shape but I also see where it looks to be broken on one end of it. I`d say it`s a mammal and very possibly Bison again. It looks to possibly be a shoulder.

La Moo.La Moo.
Looks bovine and I believe JSpencer is spot on.
Shoulder,blade, or chuck roast.

La Moo? So you think it's a french cow? Probably Limousin

C`mon Rickymouse, if it was French it would be Le Moo. La Moo is Spanish. But to add to the original posting, no a fossilized bone would not neccesarily weigh a lot more than a fresh one. I`ve handled very few of them but was actually surprised at how little they weighed after being fossilized by mineral replacement. And now you have 2 Texans saying shoulder blade from bovine.

It has a pachyderm look to it, more information of location would be helpful, but I'm thinking Mammoth Tibia, like this one
http://www.mcculloughfossils.com/tibiaa8.47.jpg

I keep forgetting about those mammoths. They weren't around that long ago. I'm sure there were other creatures about that time that were big also. Try making soup out of it for that mamoth apatite

Yeah, those sneaky elephants

Without knowing where this specimen comes from, it's hard to narrow this down much, but I suspect this is the proximal tibia (knee-end of lower back leg) from a bovine (cow or bison). Elephant tibs are *much* more bulky and about four to six times the diameter, and the mastodon and mammoth examples I've seen follow suit. The specimen reads 11 inches across, which matches closely the width of proximal tibs for wildebeest. Were it a scapula, bone breakage should be visible on the tapered tip where the lateral vanes would have attached; instead, the damage occurred only at both ends. The "gaunt triangle" shape when seen end-on is pretty typical of artiodactyl tibs, with the heavier animals having more "bloated triangles" to support more mass. The dense outer sheath of bone has worn away, exposing the usual spongy (cancellous) interior around the articulation surfaces; it's not osteoporotic, it's normal. The spongy bone isn't infilled by minerals (permineralized), so this doesn't appear to be a fossil quite yet; however, it has been transported by water, judging by the rounded corners.

To answer your other question, bone decays very quickly if exposed to sunlight and dessication--even big bones can be obliterated in a few years if exposed to direct UV all day and dried out. Shade and moisture can elongate the decay process, but the upper bound you asked about is 100 years, with the average around 2 to 5 years. Rodents, insects, fungus, and even plant roots can strongly reduce bone durability and longevity, preventing them from ever becoming fossils. As it degrades, bone goes through a progression of weathering, first degreasing, then drying and splitting, then flaking off the outer sheath of dense bone. That usually leaves a sort of "hairy" or fibrous-looking bone with large patches of the exposed interior, as we see here. I suspect this one isn't so fibrous only because of its water-tumbling transport. Whatever it is, I suspect that you have rescued it from non-fossil oblivion.

I LOVE your explanations, you are exceptionally insightful with all the things you share, stuff that others have not done over the years of 'fossiling' other who are knowledgeable.

To me it looks like a thigh bone or a shin bone but broken in half.

Just found this bone in North Port Fl by a creek, It was hanging out the side of the bank, any ideas its on my facebook, rtoyota45 under Rhonda hell gillis parker