Biological Exuberance: Animal
Homosexuality and Natural Diversity
JAMA. 2000;283(16):2170. doi:10.1001/jama.283.16.2170-JBK0426-3-1
A good thing about science is that, given enough time, it will eventually correct
itself. Biological Exuberance by Bruce Bagemihl illustrates that self-correcting process
by dispelling two prevalent myths: that reproduction is the sole reason for sexual
behavior and that homosexuality is hard to find in the animal kingdom.
The book contains two sections. In the first, "A Polysexual, Polygendered World,"
Bagemihl examines the hidden assumptions behind the way scientists interpret
homosexual behavior in animals. Assumptions that tend to explain animal
homosexuality out of existence are carefully analyzed as are the double standards often
used in characterizing behaviors as sexual when they involve members of the other but
not the same sex. This section concludes with the chapter "A New Paradigm: Biological
Exuberance." Bagemihl writes, "The essence of Biological Exuberance is that natural
systems are driven as much by abundance and excess as they are by limitation and
practicality." This hypothesis is based on the concept of biodiversity—that the vitality of
a biological system is a direct consequence of the diversity it contains. As stated
succinctly by James Lovelock, "as diversity increases, so does stability and resilience."
From this perspective, diverse sexualities, including homosexualities, should be
expected throughout the animal kingdom. Biological Exuberance thus offers a
hypothesis for the maintenance within populations of homosexual behaviors and other
behaviors that are often presumed to be at odds with reproduction.
The second section, "A Wonderful Bestiary," is organized in a field-guide format and
documents homosexuality as well as "nonreproductive and alternative
heterosexualities" in 190 species. In total, this abundantly illustrated book compiles
more than two centuries of observations of homosexual behavior, pair bonding, and
coparenting in more than 400 species. These include observations of species in which
homosexual but not heterosexual pair bonding has been documented and others in
which same-sex courtship and sexuality are so pervasive that "females are said to
`mimic' males in order to mate with them." The sheer scope and thorough
documentation of this book make it an extremely valuable resource for anyone
interested in the diversity of animal behavior and sexuality.
It is often assumed that nature has a prescriptive normative force such that what is
deemed natural is considered to be good, while the virtue of what is not found in nature
is subject to doubt. Ethical analysis shows this reasoning to be flawed. Nevertheless,
Bagemihl's convincing demonstration of pervasive nonprocreative heterosexual and
homosexual behaviors in the animal kingdom undermines one of the more common
arguments in support of the belief that it is wrong (or indicative of psychopathology) for
human beings to engage in such behaviors. "What is remarkable about the entire
debate about the naturalness of homosexuality," according to Bagemihl, "is the frequent
absence of any reference to concrete facts or accurate, comprehensive information
about animal homosexuality." Heretofore, for reasons that are examined in the first
section of the book, much of this information has been virtually inaccessible to
scholars. Biological Exuberance fills that void, and there can no longer be any excuse
for such omissions.