Rodent Societies: An Ecological & Evolutionary Perspective

fourth of all rodent genera are known to associate with
rocky habitat (fig. 35.1).

Defining an Obligate Rock-Specialist

Obligate rock-specialists — those rodents that live exclu-
sively within rocks or rocky crevices — can be called sax-
atile (meaning that they live among rocks) or petrophilic
(rock-loving). There are approximately seventy-seven spe-
cies of obligate rock-specialists in forty-five genera and
eleven different families (table 35.2). Included in this list are
two families of rodents that contain only saxatile species
(the monotypic petromurid dassie rat and the ctenodacty-
lid gundis), several genera of rodents with adaptive radia-
tions of rock-specialist species, including Australian rock-
rats (Zyzomys), high mountain voles (Alticola), rock rats
(Aethomys), chinchilla rats (Abrocoma), snow voles (Chio-
nomys), hutias (Geocapromys), and mountain viscachas
(Lagidium), and a few species that have atypically special-
ized on rocky habitat, including the punaré (the only echi-
myid or spiny rat to be predominantly petrophilic; Streilein
1982; note, however, that one population of the punaré
occurs in an area with sandy soil but no rocks; Lacher and
Alho 1989) and the montane guinea pig (Cavia tschudii,

which appears to be the only guinea pig to have been clas-

sified as an outcrop specialist; Fredericksen et al. 2003).

Sociality in Obligate Rock-Specialists

Despite the fact that there are so many saxatile rodents

found throughout the world, the extent of social behavior

exhibited by most species is virtually unknown. There are

perhaps four reasons why so little information is known

about the natural history, behavior, and ecology of most

rock-dwelling rodents: (1) many saxatile rodents inhabit

extreme environments in which it is often very taxing to

work, (2) the rocky terrain inhabited by petrophilic rodents

often makes it extremely difficult to observe their behavior,

track them, or trap them, (3) the excellent climbing abilities

and shy nature of many rock-specialists makes capturing

them an extremely complicated process (Rowlands 1974;

Lacher 1981; Streilein 1982; Nutt 2003; Zahler and Khan

2003; Spotorno et al. 2004), and (4) some rock-dwelling

species are rare, threatened, or on the verge of extinction

(Oliver 1977; Balcom and Yahner 1996; Jimenez 1996; Zah-

ler 1996).

In the following I describe the social behavior of those

rock-specialist species for which any information on social

Socioecology of Rock-Dwelling Rodents 421

Table 35.2 Rodents that are obligate rock-specialists

Family Species

Sciuridae Ammospermophilus insularis?, Atlantoxerus getulus?, Eupetaurus cinereus, Rheithrosciurus macrotis?, Sciurotamias davidianus?,
S. forresti?, Spermophilus atricapillus?, Tamias dorsalis, Trogopterus xanthipes?
Heteromyidae Chaetodipus intermedius
Muridae
Cricetinae Calomyscus bailwardi?
Gerbillinae Gerbillus campestris?, G. dasyurus?. G. lowei?, G. rupicola, Sekeetamys calurus
Microtinae Alticola argentatus, A. roylei?, A. strelzovi, Chionomys gud, C. nivalis, C. roberti, Microtus chrotorrhinus?
Murinae Acomys russatus, Aethomys chrysophilus?, A. namaquensis, A. nyikae?, Cremnomys cutchicus, Niveventer hinpoon, Rattus neilli,
Vernaya fulva?, Zyzomys argurus, Z. maini, Z. palatalis, Z. pedunculatus, Z. woodwardi
Petromyscinae Petromyscus collinus, P. monticularis
Sigmodontinae Auliscomys boliviensis, A. sublimus, Chinchillula sahamae?, Euneomys chinchilloides, Galenomys garleppi?, Nelsonia neotomodon?,
Neotoma cinerea, N. magister, N. mexicana, Peromyscus attwateri?, P. crinitus?, P. difficilis?, Phyllotis xanthopygus, Other
Phyllotis sp?, Punomys lemminus
Gliridae Dryomys laniger, Graphiurus ocularis, G. platyops?
Caviidae Cavia tschudii, Kerodon rupestris
Chinchillidae Chinchilla brevicaudata, C. laniger, Lagidium boxi, L. peruanum, L. viscacia, L. wolffsohni
Capromyidae Geocapromys brownii, G. ingrahami
Abrocomidae Abrocoma budini, A. famatina, A. schistacea, A. uspallata, A. vaccarum
Echimyidae Thrichomys apereoides?
Petromuridae Petromus typicus
Ctenodactylidae Ctenodactylus gundi, C. vali, Felovia vae, Massoutiera mzabi, Pectinator spekei

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