Squirrels of the World

Taxonomic Introduction 3

cies within the genus Ratufa), and the Sciurillinae, which is
made up of the South American pygmy squirrels (one or per-
haps several species of the genus Sciurillus). A third subfam-
ily, the Sciurinae, consists of the tree squirrels of the Ameri-
cas and northern Eurasia (tribe Sciurini) and its sister group,
the fl ying squirrels (tribe Pteromyini), as mentioned above.
A fourth subfamily, the Callosciurinae, contains the South-
east Asian tree squirrels recognized by Pocock, plus the

small striped squirrels (Funambulus) of the Indian subconti-

nent. The fi fth subfamily, the Xerinae, combines three dis-

tinct groups: the African ground squirrels (tribe Xerini); the

African tree and bush squirrels (tribe Protoxerini); and the

other ground squirrels, chipmunks, and marmots of North

America and northern Eurasia (tribe Marmotini). This clas-

sifi cation is summarized in table 1.1 and provides the orga-

nization of this book.