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differences between human and animal bones?
angry axis!
1001cranes wrote in little_details
so! like many others, I am attempting NaNoWriMo this year! without getting into the details, my universe is pretty close to ours socially, a little set back technologically, and still polytheistic in a pretty Greco-Roman way.

There is a scene in a temple/shrine where one of my characters basically notices that supposed animal bones are actually human bones. my problem is sort of two-fold. the fact that these are human bones can't be super obvious, because someone else probably would have noticed, right? But! the characters won't be able to handle the bones or be super close to them at this point (I'm sort of thinking they might have to break in later to get a better look at them, one character being sort of "okay, that looks human" and another character being like "have you lost your mind")

It's not that I haven't found information like this, but its either too simple - humans have chins! - or way way wayyyyyy above my head. I'm hoping someone here can dumb it down for me to write about, even though one of my characters would be a kind of doctor-in-training and therefore pretty knowledgeable about what they're seeing. based on what I've read, I'm assuming a fairly "easy" indicator would be cortical bone thickness, animal being quite a bit thicker than what you would see in a human, less porous, greater density? although that would be more difficult to tell if the human who was killed was a child, yes? I'm having trouble figuring out what would be possible and believable in this situation!

I just read a news story that deals with that sort of issue. A body was just found in a garden during construction. It happens to be the house where a serial killer lived. There's much ado about that, but there's a quote in the paper today that "it's obvious they were human." Let me see if I can find it because it was the police that was quoted.

Ah, here. You'll have to flip to page 2

The only animal that could look human is a chimp/bonobo or a small bear-- unless the bones are reeaaally disarticulated, but off the top of my head I've never seen any skeletons that looked at all human (I studied anthropology, so we actually compared human/animal remains for my forensic class). Most common animals you'd see in those situations are quadrupeds and they look very, very different even if you only have, say, a femur.

Basically the best bet you'd have is ribs, because those can look nonspecific at a quick glance, finger/toe bones, individual vertebrae. Spines, skulls, pelvises, and limbs just look... too not human to anyone that's gotten a look at them, and they look different even with a cursory inspection. It depends on how far away the observer is, if they're charred, partially buried, the lighting is bad, and other factors too. But if someone else has gotten a close look at them (as you suggest by your "someone else" noticing comment), it kind of jumps out at you really quickly.

Just take a look at some animal skeletons online and you'll see the differences very quickly. A lot of the structures are the same, but quadrupeds have very different shapes to their bones in their limbs.

Edited at 2011-11-02 04:09 pm (UTC)

Disclaimer: not an expert. I just play with dead things.

Have the bones been disarticulated and scattered, as you see in the decorations in ossuaries or shrines, or are these the leavings of murders or natural deaths or sacrifices that were left more or less intact? Do some of the bones still remain grouped or stuck together (parts of a spine, arm or leg bones, ribs and vertebrae together, an assemblage of wrist bones, something like that)? How many bodies, in total, would you be talking about? Are ANY skull fragments still present, especially from the lower jaw or facial area? If they are animal bones, what sort of animal might they actually be? Deer, horse, pig, bear, wolf, mountain lion? Also, what animals are they expecting to see? Because that will somewhat affect what strikes them as "wrong" soonest. If I'm expecting cow, I'm going to see a human femur and go "Waaaay too thin, guys!" but if I'm expecting a deer, a child's bone might not pip my radar right away (unless I was looking close enough to see that the epiphyses had fallen away or had not fused completely, indicating a young animal, not an adult deer). Big, heavy mammals like horses and cows have big, heavy bones with thicker shafts.

To a layman who has never handled bones, vertebrae and ribs and long bones can look a lot alike from one species to the next, when the differences will be obvious enough to a person who knows what they're looking at if they actually stop and look.

Offhand, the vertebrae and shape of the spinal column are pretty good indicators of human-ness, as is the shape of the ribcage (broad and flat, as opposed to narrow and deep), the inward curve of the ribs (quite sharp), and the shape of the pelvis. Also, the human sacrum, in terms of size and shape, is pretty darn distinctive. I think, out of all of those, I would probably notice the pelvis first. The vertebrae, maybe not, especially if they were disarticulated, unless I was expecting to see lots of animal bones, or there were enough bones that it was obvious that there were many bodies involved, and started wondering why I wasn't seeing more extravagantly long vertebrae like the ones you find in the shoulders of deer/cows/horses.

Depending on time, conditions, and how the flesh was removed (open air decomp with scavengers, closed space decomp, left in a damp place, cooked and left lying around, left lying in water, etc.) the texture and porosity and color of bones can vary pretty widely, so unless your doctor-in-training comes across a convenient perfect cross-section, the first cue will probably be shape.

I hope that was helpful.

I should also point out that large mammal bones, horses and cows and such, are pretty huge, and hard to mistake for human. Therefore, vice-versa. For more human-looking bones, you have to go to something smaller, younger, or built much thinner. Some predator animal long bones can look quite human, disarticulated.

Last note, I promise. Are they ALL human bones, are are there actually some animal bones in there? Because having some actual obvious animal bones there would maybe prime someone to see animal bones. An assemblage of human bones is kinda hard to mistake for anything else, if they are there in any quantity.

Generic bones, such as arm and leg and rib bones, could be mistaken for non-human if the animal was about the same size. So a young horse or a calf, I could see the mistake.

Pelvises, hand- and foot-bones and especially skulls--yeah, those are obvious. How are the sacrifices being killed? Are the skulls kept somewhere separate from the bodies?

Also, you may want to look up how long it takes for bodies to decompose into skeletons.

what if they sacrified both humans and animals at the temple and the bones were all mixed up and smashed up in a pile.

the human skulls are missing as they are kept seperately, but the animal skulls are there.

then those looking at it might see the skulls and assume it's animals and those that look a bit closer might get suspicious because of see a bit of a human pelvis (but if they are technologically not that advanced, why does one character know all about human bones (can't be wikipedia after all ;)) and another doesn't?)

and when they have a closer look, what others have said about spines and so on, might make them sure that there are humans in there and not just animals, especially if the animals were all cows and pigs and sheep etc, so no arms.

My qualifications: I'm an archaeologist, and just taught a section on how to identify animal bones!

To the average person, most mammal bones and humans bones (other than the skull) look pretty much identical. Believe me, my students are not good at identifying to species even when they have a book of bones right there to look at. On the other hand, if you know what you're doing, there are a lot of differences. So you could go two ways with this: either your character is an expert on the topic of animal bones for some reason (maybe one of his parents was a butcher? or a mortician?) or he notices a skull (maybe hidden under a pile of other bones so that the other characters didn't notice it).

Most people looking at, say, a deer femur really aren't going to notice it's not human, especially if they're expecting it to be human. And the reverse is true. All large mammal bones look fairly similar. An expert, though, would start to see things like the shape of the epiphyses, muscle attachments, projections, holes, etc. I don't think you need to get super-detailed for your story- that would probably just distract from the plot! If he knows about bones, it's perfectly reasonable for him to say "Hey, that's human", even if he doesn't describe the fact that it has to do with the fourth trochanter or whatever.

Fellow archaeologist here.

In the field I got pretty good at separating bones into four categories: fish, bird, sea mammal, and land mammal. I've been told that both large dog bones and deer bones can appear very human at first glance, but have more obvious differences on second inspection.

If everyone "knows" the site is full of smashed dog/deer/etc bones they won't necessarily be taking that second look if they see something "a bit humany" and it might take a really obviously human bone (skull, hips) to get people to notice. If the bone are smashed into three or four pieces and disarticulated it becomes that much trickier.

Archaeology student here that has decided that it's a nice idea to study the difference between worked human and animal bones here (just decided and starting, don't take me 100% true).

It also depends a lot on what king of bones you're talking about. And also the possibility to handle them, but as you stated OP, that's not an option at the moment.

There's a lot of small differences between animal and human bones, starting from the size (I still can't distinguish kid human bones from some animal bones -.-), to the anatomy of said bone.

One of the indicators on bones are the 'soft porous' (sorry, non-native English speaker and a little sleepy to search the correct term and forgot my usb with my bones books somewhere) bone tissue (inner tissue) is diffent from animals and humans, with humans (and 2-legged animals) this tissue is elongated to support the full upright structure, while on 4-legged animals, this tissue is more 'round', given that the weight is more evenly distributed. Also, the hand are foot bones are particular, and if we're talking about ungulated (hoofed) animals, the metacarpals and metatarsus have really distinctives forms.

The pelvis is another thing you can use, if your character is good with bones, try with the ribs and vertebraes.


It very much depends on the part of the skeleton. At first glance the paw bones of a bear can look like a human hand (the book I worked from when studying Human Skeletal Remains in Archaeology had a series of illustrations to point out what to look out for) but femurs and humeri in particular are completely different, as are pelvises - no other species has a gluteus maximus, so this is very distinctive. Tibias are a lot less obvious. Skulls - well, at a glance; look at even a cat's head and then at your own in a mirror. Even a chimpanzee's skull is completely different

If they can handle them, all I can say is that they feel completely different. We sometimes found animal bones among the bones we were studying and the moment we picked them up we would know

My parents are forensic anthropologists. Down through the years, they've had law enforcement bring them pig, deer, and bear bones as potential human crime victims. To the untrained eye, a lot of species' long bones and ribs can look human.

(And I'm sure I'm forgetting some species in there.)

Yes to all of the above: differences can be pretty obvious if you know what you're looking for, especially if you have the right bones and they're complete, but not everyone knows what to look for or looks closely. Think about it - I'm gonna go out on a limb and guess that you've eaten a t-bone steak at least once in your life. Off the top of your head, do you know what the bone in it is? Have you ever even thought about it before? If you expect something to be one way, you just don't bother to examine things, unless the discrepancy is glaring. So, if it helps, you can have the human bone be fairly obvious and people just not caring to look.

On that note, a few questions. First, about your doctor-in-training. What sort of doctor, and what sort of training? How far back are they set, knowledge-wise? Because the common taboo against desecration of human remains might render both of your characters fairly unfamiliar with the human skeleton, if you want to use that excuse.

Second, what context are these bones being found in? I assume it's not a sacrifice on display - because wouldn't that be fresh or burned meat and not just bones? Is it some sort of relic? Or is it some sort of charm? If it's the former, more people would have been looking at the bones, but they would have had more incentive to explain away discrepancies. If it's the latter, obviously it's reversed. Either way, the way people view the bones can help you.

Sorry if I'm asking foolish questions you've already considered yourself. Good luck with your story; I hope you make it!

Echoing what other people said, but may I just make a minor, non-technical plot idea - have something that's like a fore arm bone as the first thing they saw, which can result in lots of arguing on whether it's human or not. The person thinks it's human sneaks back later on, found the hands bones with something significantly human-flavour - say a ring, a watch or wrist band.

As a medical student, I can safely tell you that throw us a bone covered in mud, we can't tell what species it is either unless the person had extensive bone-related experience before! :)