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Providing evidence to improve practice

Action: Use conditioned taste aversion to reduce human-wildlife conflict in non-residential sites Terrestrial Mammal Conservation

Key messages

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  • Two studies evaluated the effects on mammals of using conditioned taste aversion to reduce human-wildlife conflict in non-residential sites. Both studies were in the USA.





Human-wildlife conflict (2 studies): Two studies, in the USA, found that lacing foodstuffs with substances that induce illness led to these foods being avoided by coyotes and black bears.

Supporting evidence from individual studies


A study in 1977–1978 at a campsite in California, USA (Cornell & Cornely 1979) found that using conditioned taste aversion reduced the number of coyotes Canis latrans that begged for food. Three months after adding lithium chloride (which induces gastrointestinal discomfort) to bait there had been no reported begging problems at the campsite, compared to >12 coyotes begging for food in the month prior to use of lithium chloride baits. Bait was consumed by coyotes 31 times over a 14-day period. From December 1977 to January 1978, meat bait was mixed with lithium chloride at a rate of 10 g/396 g of meat. Bait was left on paper plates at the campsite or thrown to individual coyotes. Animal calls were used to attract coyotes. During baiting, campsite visitors were asked not to feed coyotes. Methods for surveying coyotes were unclear in the original paper.


A study in 1992–1994 in a predominantly forested area in Minnesota, USA (Ternent & Garshelis 1999) found that inducing conditioned taste aversion through lacing military-issue meals with thiabendazole led to black bears Ursus americanus subsequently avoiding these foods. Consumption of laced meals induced illness in bears in <90 minutes. Thereafter, over 2–122 days post-treatment, bears did not consume military-issue meals offered during 32 of 41 trials and partially consumed such meals during nine trials. Only once did partial consumption comprise >50% of the meal. Other foodstuffs were, at least partially, consumed in 78% of trials. One year later, two of the bears did not consume military-issue meals in any of seven trials. However, one more year later, in a single trial, one of the bears fully consumed a military-issue meal. In May 1992, two adult female bears and three yearlings that were resident on a military reservation were each given a military-issue meal laced with thiabendazole (72–165 mg/kg bear). Bears were habituated to humans and could be studied closely without disturbance. Meals were ready-to-eat and consisted of a range of foods, each in sealed pouches and all in a sealed brown plastic bag. Subsequent trials involved military-issue meals and other foodstuffs (raw bacon, jelly, or peanut butter and jelly on bread).

Referenced papers

Please cite as:

Littlewood, N.A., Rocha, R., Smith, R.K., Martin, P.A., Lockhart, S.L., Schoonover, R.F., Wilman, E., Bladon, A.J., Sainsbury, K.A., Pimm S. and Sutherland, W.J. (2020) Terrestrial Mammal Conservation: Global Evidence for the Effects of Interventions for terrestrial mammals excluding bats and primates. Synopses of Conservation Evidence Series. University of Cambridge, Cambridge, UK.