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Why killing carnivores does not help conserve them

This might seem obvious but the U.S. government believes legal killing will help against illegal killing. They argued that in federal court in 2006 and lost, yet they continue to propose liberalized killing for grizzly bears and wolves, as a way to improve tolerance and reduce poaching. Neither the social science we have published from 2003–2015 about people’s attitudes and inclinations to poach, nor the population ecology and survival analyses we have presented since 2016 seem to have swayed this deeply held myth.

Below we review the evidence (and cite our critics), first from logic alone we identify the assumptions being made by the government and proponents of this view, next we present the evidence against the view from the perspective of population ecology, and finally from the perspective of human tolerance for large carnivores..

The logic


Treves, A., Artelle, K.A., Paquet, P.C. 2018.

Differentiating between regulations and hunting as conservation interventions. Conservation Biology 33(2): 472–475.

The evidence from population ecology


Chapron, G. and Treves, A. 2016a and b, 2017a and b.

We first showed that Michigan and Wisconsin wolf population growth slowed whenever the government liberalized wolf-killing and the slow-down was proportional to the length of time that culling was liberalized, regardless of how many wolves were killed. In 2016, we published a correction

that showed the probability that culling slowed population growth was 92%. In 2017, Pepin et al. started a lively debate when they tried to counter our hypothesis but did not succeed in our opinion. That debate improved our model which strengthened its findings, also in the pages of Proceedings of the Royal Society B. Pepin provided no evidence for a biological mechanism for density-dependent population growth as we showed in a 2017 rebuttal.

Then Stien 2017, and Olson et al. 2017 tried again. Those critiques only made our evidence stronger.

Olson et al. in particular weakened their own position by omitting methods and citing studies that were irrelevant. Furthermore, Chapron and Treves were pleased to hear of independent findings for Mexican wolves presented by David Parsons in 2014. Soon to come out in 2019, new findings by Santiago-Ávila are sure to revive the debate!

The evidence from human tolerance and inclination to poach


2014. Treves, A. Bruskotter, J.T.

Tolerance for Predatory Wildlife. Science 344: 476-477.


Take-home messages: Tolerance for predators did not reflect individual economic losses but rather social identity and peer group complaints. Intolerance for wolves and inclinations to poach wolves rose when the government culled wolves. Tolerance for wolves did not increase when wolf hunting and trapping season was implemented.


2015. Hogberg, J., Treves, A., Shaw, B., Naughton-Treves, L.

Changes in attitudes toward wolves before and after an inaugural public hunting and trapping season: early evidence from Wisconsin’s wolf range. Environmental Conservation, doi 10.1017/S037689291500017X.


2015. Browne-Nuñez, C., Treves, A., Macfarland, D., Voyles, Z., Turng, C.

Tolerance of wolves in Wisconsin: A mixed-methods examination of policy effects on attitudes and behavioral inclinations. Biological Conservation 189: 59-71.