edited by Jennifer Sills
LETTERS I BOOKS I POLICYFORUM I EDUCATION FORUM I PERSPECTIVES
More than Numbers
IN THEIR REVIEW “STATUS AND ECOLOGICAL EFFECTS OF THE WORLD’S
largest carnivores” (10 January, DOI: 10.1126/science.1241484),
W. J. Ripple et al. assess threats to carnivores and urge that minimum
population densities be maintained for persistence of large carni-
vores, biodiversity, and ecosystem structure. We argue that carni-
vore conservation is not just a numbers game. Life history strategy
(including number of offspring, life span, and diet) and behavioral
ecology (behavior that evolves from ecological pressures) of the
species in question should also guide management approaches.
For example, in social species, group survival can be critically
dependent on maintaining a certain number of individuals within
the group (1) [to enable cooperative hunting, for example (2)].
Consideration of such a threshold, and the risks of falling below it,
are often absent from carnivore management programs. Yet this factor
may explain the pattern of higher extinction rates in social carnivores,
relative to solitary carnivores (3). The important contrast between the
number of individuals in a population and the number needed to sustain social group persistence could also explain Ripple et al.’s observation that solitary pumas are more successful than group-living gray
wolves under similar conditions. Indeed, it is thought that the slowed
recolonization rates for the gray wolf (Canis lupis) in the U.S. Greater
Yellowstone ecosystem were due to a lack of mates with which dispersing animals could create new breeding units (4).
Diet plays an important role as well. With the exception of one
herbivorous panda, only large carnivore species (≥2.4 kg) catego-
rized as strict meat eaters are listed by the International Union for
the Conservation of Nature (IUCN) as critically endangered, endan-
gered, or threatened (5). In
contrast, all insectivores are
classified as least-concern.
An exclusive meat diet may
signal particular vulnerability to human conflict, which
is associated with increased
likelihood of livestock depredation and/or increased
human perceptions of risk.
Infectious disease may also
present a particular threat to
social carnivores as a consequence of increased contact
between individuals, disease
mortality, and loss of individuals below some critical threshold (6).
We urge consideration of life history strategy and social behavior
in the development of carnivore management strategy.
KATHLEEN A. ALEXANDER* AND CLAIRE E. SANDERSON
Department of Fisheries and Wildlife Conservation, Virginia Tech University, Blacksburg,
VA 24061, USA and CARACAL, Centre for Conservation of African Resources: Animals,
Communities, and Land Use, Kasane, Botswana.
*Corresponding author. E-mail: email@example.com
1. W. C. Allee, Animal Aggregations: A Study in General Sociology (Univ. of Chicago Press,
2. F. Courchamp, D. W. Macdonald, Anim. Conserv. 4, 169 (2001).
3. J. Muñoz-Durán, Evol. Ecol. Res. 4, 963 (2002).
4. A. Hurford, M. Hebblewhite, M. A. Lewis, Theor. Popul. Biol. 70, 244 (2006).
5. The IUCN Red List of Threatened Species ( www.iucnredlist.org/).
6. C. E. Sanderson, S. E. Jobbins, K. A. Alexander, Popul. Ecol. 1 (October 2013).
Politics in Play
IN THEIR REVIEW “STATUS AND ECOLOGICAL
effects of the world’s largest carnivores” (10
January, DOI: 10.1126/science.1241484),
W. J. Ripple et al. propose the creation of
a Global Large Carnivore Initiative (GLCI)
endorsed by bold commitments from politicians around the world. However, large carnivores deliver political services in addition
to ecological services, and this complication
may prevent a GLCI from gaining strong
Conflicts involving the political response
to large carnivores raise controversial questions about land-use and political economies. The animals serve as a powerful symbol to communicate difficulties (often those
that they revealed but did not create) and to
influence policies. Opposing the recovery
of large carnivores or limiting their populations has therefore become an inexpensive
way for politicians to pose as defenders of
particular interest groups that they might
An illustrative example is the decline
of sheep farming in France. French sheep
farmers claim that wolf attacks threaten
their livelihoods (1). However, this story
overlooks political factors. In 1985, French
Special Forces sank Greenpeace’s flagship
boat in Auckland harbor to prevent protests
against nuclear tests. As part of the com-
pensation, France agreed to not take mea-
sures that could hinder the import of New
Zealand lambs into the European Union (2).
This sudden end to France’s protectionist
standing has been a tough economic chal-
lenge for French sheep farming. Since the
wolf naturally came back to France from
Italy in 1992, some French politicians took
the opportunity to stand for national sheep
farming by dramatizing the impact of live-