Where can I find a reasonably accurate estimate of the number of
mammals in the world (numbers of individuals, not numbers of species),
and the proportion of these that are rodents? Additionally, are there
any guesses as to the percentage of the world's mammalian biomass that
is rodent?

Hi hyw,

Rats Have Rights:
"Rodents constitute 40% of the world's mammal population."
http://www.ratshaverights.org/info.html

Cheers,
hummer

Hi,

That's probably based on a species count. Macdonald?s New Encyclopedia
of Mammals gives ?4600 or so? mammal species and 1999 rodents, about
43% (lower if you take the erroneous estimate of 1500 species from the
site you gave). I'm prepared to believe that it is an estimate of
individuals if stated specifically, but I'm not convinced that that is
what the site did.

Thanks!

Yan

Hi again hyw,

I hadn't really posted the "Rats Have Rights" link as a possible
answer - I just thought you may enjoy it.

However, my son, who is in university studying wildlife biology, is
home for a few days. He suggested that you have a look at the
following link. It doesn't answer your question specifically, but you
would be able to make rough estimates using some of the figures
provided.

The Balance of the Fauna:
http://www.teaching-biomed.man.ac.uk/uploads/public/bio/BS369/website/lecture-4.htm

He said he may be able to help you further if you provided him with
some background/reasons for the question/answer.

Thanks,
hummer

Thanks, the link you gave is very useful for Britain, and gives me a
paper trail to start on. I hadn't thought about restricting the figure
in this way. A useful report mentioned in one of the references on
that site seems to be

Harris et al. (1995) A review of the status of British mammals, JNCC
Peterborough.

I'll look for references to this, and if I find any that use it to
extrapolate to the world, you can consider the question answered
(don't stop looking yet, though! thanks). I'd be surprised if no-one
has come up with a world estimate for the number of mammals. The
rodent figure will be more tricky (in fact, either figures for
rodents, or for Glires (rodents+lagomorphs) would do, but I suspect
this is even less likely to be floating around).

The reason that I need it is as a throw-away comment in a popular
science book about the evolution of life. At the point rodents are
mentioned, I would like to impress people with some figures of rodent
domination (!). Ideally I need a published reference to back it up.

Glad to hear that your son is studying biology: I hope he is enjoying
it!

Yan