# What's the average Body Composition by Volume?

1. May 19, 2015

### Nanako

Hi. I'm trying to write some anatomical systems for a game i'm coding, and i need some good data to work from.
Our game is about dogs, not humans, but i figure a human will be close enough

What I'd really like is a case study of a specific organism, and i'd like to know the compositions, by volume, of the various types of matter in its body. Specifically i'm interested in: Muscle, bodyfat, bones, and etc (everything else can fit under one group as far as i'm concerned. Blood, organs, glands, etc)

I have some rough values that i found elsewhere for masses, that an average human is roughly 40% muscle, 20% fat, and 40% other matter, but these values in isolation aren't actually useful to me without some volume data.

My end goal is to calculate a reasonably accurate mass for a creature, given its volume, and the known densities and volume ratios of the aforementioned matter types. Volume is something i can find quite easily by examining the creature's mesh in code, so i have that value to a high precision.

Can anyone help out with some studies, websites, or general biological data?

2. May 19, 2015

### Drakkith

Staff Emeritus
Well, a quick search is telling me that the volume of the average human body is 66.4 liters. 66.4 liters of water has a mass of 66.4 kg, which is 146.4 pounds. I'd say that treating your creatures as if they have the same density as water should get you pretty close to real value, and it's a lot easier to calculate than your method is.

3. May 19, 2015

### Drakkith

Staff Emeritus
Further searching supports the idea that the human body has approximately the same density of water, so I think treating your creatures as having the same density of water should work fine.

4. May 20, 2015

### Nanako

hi drakkith, that is pretty interesting, however it is a little TOO simple. I'm giving creatures variable anatomy (muscle.bodyfat levels) depending on factors like diet, and training. and i would really like to incorporate the difference between the density of fat and muscle in there. i'll keep water density in mind as a backup, but i would still hope to have some more specific data to work with.

What would be really great is if someone had done a reigorous body composition autopsy on an average human corpse, and tested all the indivudla components in mass and volume. Has such a thing ever been done? that would be invalueable/

5. May 20, 2015

### Drakkith

Staff Emeritus
Hope this helps.

Per this paper: http://biomed.gerontologyjournals.org/cgi/content/full/56/5/B191#R23 [Broken]
Mammalian skeletal muscle density is approximately 1.06 g/cm3.

Per this paper: http://www.ncbi.nlm.nih.gov/pubmed/1864799?dopt=Abstract&holding=npg
Fat tissue is approximately 0.90 g/ml (equivalent to 0.9 g/cm3)

Last edited by a moderator: May 7, 2017