Public database of animal specifications
You might be interested in the PanTHERIA database for several thousand mammalian species.  It has up to 53 characteristics for each species (but many fields have no entry).  It is available as two plain text files, each with one line per species (plus header line) and fields separated by tabs.  The files and data descriptions are available at http://esapubs.org/archive/ecol/E090/184/