Mammalian Body Temperatures

J. Moore (
Sat, 14 Oct 95 10:48:00 -0500

There has been a recent question about body temperature which
demonstrated a limited understanding of the subject:

> Any reasons, using fundamentals of biological processes which people
> like must have in abundance, for the temperature of
> 98.6?
> why this temperature and no other.

The following is from a couple of my previous posts on the subject
of mammalian body temperature (originally in reply to some mistaken
assumptions and claims from Troy Kelley):

TK> Why do I need to provide a source for this statement? Everyone knows
TK> that a person with 104 temperature is ill. Look it up in any medical
TK> textbook.
Tk> Troy Kelley

The fact is that body temps are *not* steady, but fluctuate depending
on activity, stress, etc. I thought most people realised this common
sense fact, but somehow I'm not surprised to find in you an exception.
I'm sure you noticed (well, actually I'm sure you *didn't notice) when
you were reading about marathon runners to see how much they sweat, that
they often run temperatures of up to 41 degress C (105.8 degrees F).
They aren't "ill", much less "deathly ill". Didn't you even *think*
of looking this up before you posted?

This of course creates problems in getting "normal" ranges for non-human
primates, as they object to being strapped down in restraints. Believe
it or not, these animals don't just "sit there and say 'ahh'". This
naturally results in higher temperatures being found, just as they would
in humans if the common method of tempertaure taking was to chase down
the subject, strap them onto a restraint board, and have beings of
another species push thermometers up their rectums.

To wit:
"In most cases, they are likely to represent normal ranges, but normals
are difficult to establish for animals which readily become excited when
restrained." (pg. 602: 1987 *The Care and Management of Laboratory
Animals* Trevor Poole, ed. Longman Scientific and Technical: Harlow,

TK> In fact, (no I don't have a source for this) I would venture to say,
TK> it is one of the lowest of all primates.

Why is your theory, unlike any scientific theory, to be granted this
special "no references needed" treatment?

TK> Also, the temperature fluxuation for humans is very
TK> narrow, which is consistent with aquatic creatures, and inconsistent
TK> with savanna creatures.
TK> Troy Kelley

As we see in the above discussion of body temperature normals, the
"normal" human range as mentioned in most medical texts are taken in a
different manner than the "normals" of other animals. They have to be,
as these other animals are necessarily, and understandably, more
stressed than humans during the temp-taking procedure. We also see that
the *actual* human range extends quite a lot higher than the "normal"
represented by relaxed human subjects, as seen in the "98-99 degrees C"
range mentioned in medical texts. Your (unsupported) claim is therefore

Jim Moore (

p.s. The following are some body temperature "normals" for various
mammals. In any discussion of body temperatures, the variablity
of these "normals" must be kept in mind, as explained above.

1987 *The Care and Management of Laboratory Animals*
Trevor Poole, ed. Longman Scientific and Technical: Harlow, Essex.

*Macaca mulatta* 36-40 degrees C
*Macaca fascicularis* 37-40 degrees C
*Papio hamadryas* 36-39 degrees C

1991 *Environmental and Metabolic Animal Physiology* 4th edition.
C. Ladd Prosser, ed. Wiley-Liss: New York.

pg. 111 (from Table 1):
Man 37 degrees C
Baboon 38.1 degrees C
Mountain sheep 37.9 degrees C night
Mountain sheep 39.8 degrees C
Goat 37-40 degrees C
Fur seal 38 degrees C
Humpback whale 36 degrees C
Bat (*Dobsonia*) 37 degrees C
Bat (*Dobsonia*) 37 degrees C
Did you know that our body temp is similar to that of some bats?
This isn't as much of a shock as you might think, since actually
mammalian body temperatures, except for monotremes and some marsupials
and a few other "primitive" mammals, cluster around a fairly tight range,
from about 34-40 degrees C.

About those whales, the ones you say have a body temp so similar to
ours. You didn't happen to do any *research* on those, did you? (I
think we all know the answer.) Let me help:

pg. 301 (after giving the body temperatures from many studies of whales):
"For the time being, at least, we may take it that the average body
temperature of Cetaceans in general is about 95.9 degrees F. -- a very
low figure indeed for a mammal.
"This figure is 2.5 degrees F. below that of man, whose temperature is
low in turn when compared with that of horse (100.4 degrees F.), of
cows and guinea-pigs (101.3 degrees F.), of rabbits, sheep and cats
(102.2 degrees F.), and of goats (103.1 degrees F.). Only hedgehogs
are known to have an average summer temperature equal to that of
cetaceans, while sloths, opposums, and duck-bills (89.6 degrees F.-93.2
degrees F.) are even more cold-blooded. But then the last-named species
occupy such a special position among mammals in so many respects, that
we may say that compared with terrestrial mammals, whales have a very
low temperature. Seals and related species certainly have higher
temperatures, for Clarke has measured 98 degrees F. in an elephant seal.
The hippopotamus, on the other hand, has a temperature similar to
cetaceans (96 degrees F.), and sea-cows probably have a lower
temperature still."

1979 *Whales* by Dr. Everhard J. Slijper (Professor, Zoological
Laboratory, University of Amsterdam). Hutchinson of London: London.

* Q-Blue 2.0 *