recent speciating derivative of the Spalax ehrenbergisuper-
species, which possibly evolved because of the barrier of the
Sinai Desert from the Israeli mole-rats during Holocene or
Pre-Holocene times, i.e., 10,000 –20,000 years ago.
Prospects
It is now a true challenge to explore all isolates of the Spa-
lax ehrenbergisuperspecies in North Africa and examine
their genetic, chromosomal, and behavioral patterns. These
future studies could highlight the extraordinary evolution-
ary processes of adaptationand speciationin marginal des-
ert environments and elucidate the origin and evolution of
sociality in the spalacids from solitary, territorial, and ag-
gressive behavior of Israeli S. ehrenbergi.
Summary
The spalacids are Eurasian, primarily East Mediterranean
subterranean rodents well adapted for life underground
ecologically, genetically, morphologically, physiologically,
and behaviorally. They are solitary, territorial, and aggres-
sive. The Spalacidae originated 40 – 45 million years ago in
Asia Minor and spread into increasingly steppic environ-
ments into the Balkans, Ukraine-Russian, and Near-East
and North African steppes, budding new species, primarily
by chromosomal speciation, with 2n38 – 62 positively
correlated with aridity. The Near Eastern branch of Spalax
ehrenbergisuperspecies consists of at least twelve allospe-
cies, four of which have been studied extensively in Israel as
an evolutionary model of adaptive climatic radiation and
peripatric speciation: Spalax galili, 2n52, in mesic, cool
Upper Galilee; S. golani, 2n54, in semixeric, cool Golan
Heights; S. carmeli, 2n58, in mesic, warm, central Israel;
and S. judaei, 2n60 in warm, dry Samaria, Judea, and
northern Negev Desert.
Aggression in theSpalax ehrenbergisuperspecies is poly-
morphic within sexes, populations, and species involving
militant, intermediate,and pacifistbehavioral phenotypes.
Pacifism increases toward the Negev Desert in Israel and
culminates in total fixation in a newly described pacifistic
species with 2n60 bordering the Sahara Desert in Egypt
and North Africa. The new North African species was iden-
tified on morphological, behavioral, chromosomal, and al-
lozyme grounds. In contrast to all other spalacids, this
species is pacifistic and presumably evolved sociality in ac-
cordance with the aridity-food distribution hypothesis. Also
a desert habitat presumably selects for pacifist behavioral
phenotypes to minimize overheating, water, and energy ex-
penditure. Social evolution may be driven by harsh ecolog-
ical conditions. Thus, adaptive radiation of spalacids in
North Africa stressed by desert ecology led to speciation
coupled with social evolution. Future studies in North Af-
rican spalacid isolates could elucidate the extraordinary
evolutionary processes of adaptation and speciation in mar-
ginal desert environments.302 Chapter Twenty-Five