toward females. Populations may be isolated, semi-isolated,
or even continuous in the main ranges (Nevo 1979, and, for
example, in Israel, Nevo et al. 1982, fig. 25.4).
Recruitment is low. Breeding usually starts in the second
year; females usually have one litter per year, which is often
their sole litter in life, although they average three (ranging
from 1 to 6; Dukel’skaya 1935; Ognev 1947; Nevo 1961,
1999; Savic ́ 1973, 1982). Maximal recorded lifespan in
captivity was 15 years (Savic ́ and Nevo 1990), but the av-
erage lifespan in nature is about 3 years.
Burrow systems and dimensions vary with age, sex, habi-
tat, productivity, soil, climate, and other environmental fac-
tors (Ognev 1947; Nevo 1961; Savic ́ 1973, 1982; Heth
1989). Burrow systems range from 30 to 250 m total length;Evolution of Pacifism and Sociality in Blind Mole-Rats 293Figure 25.3 Breeding mound of the blind mole rat, Spalax carmeli, 2n58, Spalax ehrenbergisuperspecies in Israel: (a) A breeding mound
surrounded by regular nutritional mounds; (b) linear alignment of breeding mounds rising on a slightly raised ridge to avoid ground water
level; (c) cross section of a natural breeding mound (note the nest in the center and storage chambers on the periphery); (d) diagrammatic
section showing three layers: nest, storage chambers with bulbs, corms, roots, and sanitary chamber(s) (from Nevo 1961; photo E. Nevo);
(e) small nutritional mounds radiating from a big breeding mound, with a hoe on top for scale (Photo K. Rybalko).