Our objective in writing Squirrels of the World is to provide a
book that exhibits the great diversity of squirrels, describes
some of their biology, and is illustrated with photographs and
distribution maps for all species. Unfortunately, photographs
were not available for all of the squirrel species, despite the
eff orts of our many photographic collaborators, who contrib-
uted images of 231 out of the total of 285 species that we rec-
ognize in this book. In preparing the maps, we discovered
that many of the published distribution maps are inaccurate.
Accordingly, we carefully checked the described distribu-
tions of each species and based the maps on documented re-
cords of occurrence. Our knowledge of species and distribu-
tions continues to change, but we have endeavored to provide
the most accurate assessments available.
Our format is straightforward, starting with the scientifi c
name, followed by the name of the person who described it
and the date of the description, the common name, a brief
description of the species, including some measurements,
and its overall distribution. In the section on geographic vari-
ation, we provide the scientifi c names of the subspecies we
recognize, their geographic range, and characteristics used to
distinguish them. In some species, the subspecies are remark-
ably distinct from one another. Our goal is that our readers
will be able to identify the species and subspecies of the squir-
rels that they observe. We then comment on the conserva-
tion status, although frequently the abundance of a species is
poorly known. Finally, we supply a brief description of the
preferred habitat of the species, and a summary of what is
known about its natural history. We hope that the extreme
brevity of natural history information for many species will
serve to stimulate further research.
This book is a compilation from many sources. In order to
facilitate reading, we do not include citations to our sources
within the text. However, at the end of each species account
we supply a reference section, giving a brief citation for the
publications we have used, which are subsequently cited
in full in the bibliographic section at the back of the book.
The online International Union for Conservation of Nature
(IUCN) Red List of Threatened Species, version 2010.3, provided
information for the conservation status of each species and
many of the range maps. We include the IUCN online refer-
ence for an individual species account in our book only if
we used information from it beyond t he conser vation status
and the map. This format should allow interested readers
access to the rich literature on squirrels.
Normally a mammalian account includes illustrations of
the skull. Instead of this we provide illustrations of the
skulls of most genera of squirrels in an appendix. We hope
this will assist in the identifi cation of museum specimens,
fi eld discoveries, and fossils.We are grateful for our assistants who have helped us pre-
pare this book, particularly Paula W. Bohaska of the Smith-
sonian Institution, Maressa Takahashi of Columbia Univer-
sity, Jennie Miller of Yale University, Hsiang Ling Chen and
Katharine Derrick of the Conservation Research Laboratory
at the University of Arizona, and Melissa Bugdal of Wilkes
University.Abbreviations
HB head and body length measurement
HF hind foot measurement
IUCN International Union for Conservation of Nature
T tail length measurement
TL total length