The graph below was put together by Waylon Ramming based
on information in the working terrier data table at www.terrierman.com/table2.htm
The graph below is broken out by sex, and by
quarter inch increments.
Of the 355 working terriers
aggregated below, 200 are bitches and 155 are
dogs.
Of the 200 bitches, 99 are 12 inches
tall or less.
Of the 155 dogs, 37 are 12 inches
tall or less.
The AKC standard for the Jack Russell
Terrier lists the minimum size requirement for
the Jack Russell at 12 inches.
The Jack Russell Terrier Club of America has
a bifurcated standard that recognizes dogs 10 to 12.5
inches tall in one class, and dogs 12.5 to 15 inches tall
in another class.
The skewed sex ratio we find in the field
among working terriers is quite remarkable when one
considers that unspayed bitches
are often unable to work due to heat cycles and
pregnancy.