Conditioned taste aversion: A field application to coyote predation on sheep

doi:10.1016/S0091-6773(77)90568-5

Behavioral Biology

Volume 20, Issue 1, May 1977, Pages 91-95

https://doi.org/10.1016/S0091-6773(77)90568-5 Get rights and content

Predation by free ranging coyotes (Canis latrans) on two sheep herds was inhibited by a procedure in which sheep carcasses laced with toxic lithium chloride were placed adjacent to the herds. When the lithium chloride bait was removed or replaced with nontoxic sodium chloride bait, bait takes and suppression of attacks on live prey continued. The blocking of attack behavior had not extinguished after 9 weeks at the termination of the study.

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Assessment of sheep losses

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Cited by (31)

Successful conditioned taste aversion in jaguars
2023, Applied Animal Behaviour Science
Chemical induction of a conditioned taste aversion (CTA) has been successfully tested since 1976 on a variety of predators, yet its adoption as an anti-predation tool is still undeveloped. In this paper we describe the results of the application of CTA on six captive jaguars (Panthera onca) using Thiabendazole (TBZ). Jaguars are considered endangered in Mexico but are illegally killed by ranchers in retaliatory reactions to real or perceived livestock predation. Hence, CTA could potentially provide an important tool to reduce livestock predation and protect jaguars. Between 2015 and 2016, we used TBZ in meat baits for six captive jaguars. We mixed a dose of 400 mg/kg of TBZ in a prepared bait using ground meat wrapped in the skin of selected domestic species. TBZ induced a conditioned taste aversion in all treated jaguars. Additionally, we report on two treated free-ranging known calf-killing and dog-killing jaguars who displayed a spatial avoidance after being treated. We suggest further trials be conducted in the wild with GPS collared animals. Properly applied, TBZ may become a useful tool to mitigate predator-livestock-human conflict, especially for endangered species.
The effectiveness of conditioned aversion in wolves: Insights from experimental tests
2020, Behavioural Processes
Citation Excerpt :
In a previous study, we increased the survival of translocated rabbits sprayed with vanilla essence after inducing odour aversion with microencapsulated levamisole plus vanilla essence in rabbit meat baits in the release areas (Tobajas et al., 2020c). In the livestock predation context, several studies in both the laboratory and the field have shown that a proportion of coyotes can acquire aversion to baits of a specific prey, and subsequently learn to avoid live prey (Gustavson and Nicolaus, 1987; Gustavson et al., 1976; Ellins et al., 1977); however, these studies have several drawbacks (Table 1). In fact, subsequent experiments failed to replicate these findings (Bourne and Dorrance, 1982; Burns, 1983).
It has been suggested that conditioned food aversion (CFA) could be a potential non-lethal intervention by which to deter attacks on livestock by large carnivores. CFA occurs when an animal associates the characteristics of a food with an illness, thus rejecting that food in subsequent encounters. CFA can be associated with an artificial odour during conditioning. Despite the debate surrounding the use of this intervention, more studies evaluating the effectiveness of CFA are necessary. We experimentally evaluated the potential of microgranulated levamisole + a vanilla odour cue to induce CFA in captive Iberian wolves (Canis lupus signatus). Four out of the five wolves treated showed an aversion to the meat for a minimum of one month after conditioning. The microgranulated presentation masked the flavour and smell of the levamisole but increased its volume, which may have facilitated its detection by the wolves. We also observed that the strength of the odour played an important role in the aversion extinction. The use of microgranulated levamisole + an odour cue has the potential to be used as an intervention by which to induce aversive conditioning in wolves in the wild, although rigorous field tests are required. We discuss the potential of CFA to deter attacks on livestock by large carnivores.
Using conditioned taste aversion to reduce human-nonhuman primate conflict: A comparison of four potentially illness-inducing drugs
2020, Applied Animal Behaviour Science
Citation Excerpt :
Those with a moderate aversion take more than 15 min to eat a preferred food, while those with a strong aversion refuse to eat a preferred food and may even show some uneasiness while near the food. CTA has been used effectively in wildlife conservation and management to reduce coyote and wolf predation on sheep (Ellins et al., 1977; Gustavson et al., 1976), raven and raccoon predation on eggs (Avery et al., 1995; Nicolaus and Nellis, 1987), and bear consumption of pre-prepared meals (MREs) that they sought out and consumed previously (Polson, 1983; Ternent and Garshelis, 1999). In these studies, a food item that the animals actively targeted was treated with an aversive compound, and after the animals consumed the treated food and became ill, they avoided the food item.
Human-wildlife conflict in the form of crop- and livestock depredation is escalating worldwide and many species of nonhuman primates are considered serious crop pests throughout areas within their ranges that humans inhabit. Animals become habituated to many non-lethal mitigation strategies, which then become ineffective at reducing crop-foraging intensities by nonhuman primates, so people have turned to culling to reduce crop losses. An example of this problem is primate crop depredation in northern India, where rhesus macaques (Macaca mulatta) have been declared vermin. Conditioned Taste Aversion (CTA) develops when humans and nonhuman animals associate the taste and odor of food with post-consumption illness and results in subsequent refusal to consume the food associated with illness. The length of time that the food is avoided indicates the aversion’s strength. CTA can be induced deliberately when food is paired with a drug that causes nausea. Thus, exploiting CTA could be a non-lethal and effective method to control crop damage caused by vertebrate pests. We tested four drugs on 88 rhesus macaques to assess their ability to induce a CTA and determine safe and effective doses. Our results suggest that fenbendazole, an anthelminthic drug with a high margin of safety, is ineffective. A similar drug, levamisole also was ineffective, as the monkeys detected it during the acquisition phase. However, we were able to create aversions using thiabendazole, another anthelminthic, and 17 alpha-ethynyl estradiol (EE). Once a dose appropriate to induce a CTA was determined, EE demonstrated a success rate of 86 %, and thiabendazole 46 %. Both drugs have strengths and weaknesses. Only a small dose of EE (25 mg/kg of body weight) was required to induce a CTA, which can be concealed in a small amount of food. However, it is a synthetic hormone, so access to the drug should be limited, and its distribution in the environment controlled. Thiabendazole required a considerably higher dose (160 mg/kg of body weight) to establish a CTA and may be a greater challenge to conceal. Nonetheless, both drugs appeared to go undetected in these tests and could be used with mild baits, e.g., wheat and corn/maize. We urge continued conditioned taste aversion studies across species to reduce crop damage.
Conditioned taste aversion in the grey fox (Pseudalopex griseus), in Southern Argentine Patagonia
2015, Applied Animal Behaviour Science
Citation Excerpt :
Second, it could be used to generate CTA to livestock using beef hides retaining the typical taste and scent of domestic livestock prey on the outer surfaces wrapped securely around ground meat. This was indicated by Ellins et al. (1977) in coyotes, inhibiting predation between two sheep herds using sheep carcasses laced with lithium chloride, adjacent to the herds. Since Levamisole may be safer and easier to work with than lithium chloride and our results indicate that it produced reliable aversion among grey foxes, it might be a worthy addition as a management tool for wild populations.
Attempts to control cougar (Puma concolor) and culpeo fox (Pseudalopex culpaeus) populations in Patagonia through poisoning, negatively affects grey foxes (Pseudalopex griseus) and many other non-target species. It is therefore advisable to develop selective predator control methods. Among a wide range of potential methods, are those based on manipulating the behaviour of non-target species. Conditioned taste aversion (CTA) develops when an animal associates taste with subsequent illness, and, after recovery, avoids the referent taste. Food aversions can be potentially useful in efforts to reduce losses of non-target species when lethal baits are distributed to control other predators. We evaluated two ways to add the aversion agent Levamisole hydrochloride to a bait to generate CTA in grey foxes. We established one control (without Levamisole) and two treatments: plain Levamisole and an ion-exchange resin complex (resinate: Amberlite^® IRP-64) aiming to mask the taste of Levamisole. Foxes that ate plain Levamisole baits, ate fewer baits than those in control (26.7% plain Levamisole baits vs. 83.3% untreated baits, P = 0.002) even after plain Levamisole was no longer present in the baits (40.0% vs. 86.6% untreated baits, treatment and control respectively, P = 0.007). Foxes that ate Levamisole resinate baits, also ate fewer baits than those in control (50.0% Levamisole resinate baits vs. 83.3% untreated baits, P = 0.043) but then resumed consumption when baits no longer contained the Levamisole resinate (73.3% vs. 86.6% untreated baits, treatment and control respectively, P = 0.329). Thus, foxes that failed to detect the plain Levamisole in baits acquired CTA to the bait. Contrary to our expectations, foxes detected the Levamisole resinate, associated illness with it and so resumed eating baits as soon as the resinate was withdrawn. Additionally, in the control, where foxes were familiar with untreated “safe” baits, we repeated the treatment with Levamisole resinate baits to test latent inhibition (decrement in conditioning to a stimulus as a result of its prior exposure). We found that treated bait consumption did not decrease as before, during a similar number of days (76.6% Levamisole resinate baits vs. 83.3% untreated baits, P = 0.631), suggesting that latent inhibition prevented development of CTA within our experimental time period. CTA induced among grey foxes that consume plain Levamisole baits might spare them from being poisoned in attempts to control other species of predators.
Learned food aversion with and without an odour cue for protecting untreated baits from wild mammal foraging
2007, Applied Animal Behaviour Science
Lethal methods of controlling wildlife foraging damage may present difficulties regarding conservation, ethics, welfare, and efficacy, providing an imperative to develop non-lethal alternatives. Learned food aversions offer a benign, targeted alternative to culling. However, food aversions are more readily associated with taste than with non-taste cues, and successful management applications have been limited primarily to reducing (bird) damage to treated items. To determine whether untreated foods might be protected without becoming damaged through sampling (tasting), we tested the role of an odour cue in learned food aversions with wild mammals using three conditioning treatments: (a) a combination of ziram (aversive agent) and clove oil (novel odour); (b) ziram; (c) clove oil. We tested two predictions: (1) ziram will produce learned aversion towards untreated foods; (2) training with the ziram–clove combination will produce enhanced aversion towards untreated foods in the presence of a clove odour cue. We collected detailed behavioural data from free-ranging animals using video surveillance. With European badgers Meles meles, both ziram treatments invoked innate aversion to baits. Ziram did not produce learned aversion to untreated foods, but conditioning badgers with the ziram–clove combination produced learned aversion towards untreated foods in the presence of the odour cue. The clove control did not affect badger behaviour. Our results support the second, but not the first, prediction with badgers. Red foxes Vulpes vulpes attended the ziram and the clove treatments only. Foxes displayed innate aversion to ziram, and subsequently developed learned aversions to untreated baits. Our results with foxes therefore support the first prediction, but we were unable to test the second. Learned food aversions using odour cues could potentially provide non-lethal protection for untreated foodstuffs, such as eggs, crops, and fruit, from mammalian pest species.
Perceived effectiveness of livestock-guarding dogs placed on Namibian farms
2005, Rangeland Ecology and Management
Citation Excerpt :
Livestock losses can have a severe economic impact on farmers, especially in poorer farming regions of the world (Oli et al. 1994; Hussain 2003), and many losses are attributed to predators (Andelt 1992; Andelt 1999). A wide variety of techniques aimed at reducing livestock depredation have been developed, such as the use of electric fencing, lethal predator control, toxic collars, disruptive stimuli, and various aversive techniques (Shivik et al. 2003; Treves and Karanth 2003), and such strategies have been employed on farmland with varying degrees of success (Ellins et al. 1977; Forthman Quick et al. 1985; Veeramani et al. 1996). However, such methods are often relatively costly in terms of equipment, technology, and/or labor, and these costs can be prohibitive in many situations, especially in developing countries (Treves and Karanth 2003).
Evaluations of 117 livestock-guarding dogs placed on Namibian farms between January 1994 and November 2001 were conducted as part of a study aimed at reducing livestock depredation rates on both commercial and communal farmland. The perceptions of livestock farmers were evaluated in terms of their satisfaction with the guarding dogs, the level of care given to the dogs, and the attentiveness, trustworthiness, and protectiveness of the dogs. Guarding dogs were very successful in terms of reducing livestock losses, with 73% of responding farmers reporting a large decline in losses since acquisition of a guarding dog, and the same percentage seeing an economic benefit to having the dog. Farmer satisfaction with the dogs was high, with 93% of farmers willing to recommend the program, and the care given to the dogs was also good. The dogs exhibited high levels of protectiveness and attentiveness, although trustworthiness was relatively low. The level of care provided by farmers was lower for older dogs than for younger dogs, and older dogs appeared to be less trustworthy than young dogs. There were no obvious differences in effectiveness between the sexes, or between dogs placed on communal farms and those on commercial ranches. The majority of dogs exhibited behavioral problems at some stage, particularly chasing game, staying at home, and harassing livestock, but corrective training solved 61% of the reported problems. We conclude that with the correct training and care, livestock-guarding dogs can be an effective method of livestock protection on Namibian farmlands.
Se condujeron evaluaciones con 117 perros guardianes colocados en granjas de Namibia entre Enero de 1994 y Noviembre del 2001, como parte de un estudio encaminado a reducir las tasas de depredación de ganado tanto en granjas comerciales como en granjas comunales. Se evaluaron las percepciones de los granjeros en términos de su satisfacción con los perros guardianes, el nivel de cuidado dado a los perros y la cordialidad, confiabilidad y grado de protección brindada por los perros. Los perros guardianes fueron muy exitosos en términos de reducir las perdidas de ganado, el 73% de los granjeros respondió que hubo una gran disminución de las perdidas desde la adquisición de los perros guardianes y el mismo porcentaje vio que el tener los perros es un beneficio económico. La satisfacción de los granjeros con los perros fue alta, el 93% de ellos granjeros están de dispuestos a recomendar el programa y el cuidado proporcionado a los perros fue bueno. Los perros mostraron niveles altos de protección y cordialidad, aunque la confiabilidad fue relativamente baja. El nivel de cuidado dado por los granjeros fue mas bajo para los perros viejos que para los jóvenes y también los perros viejos parecieron ser menos confiables que los jóvenes. No hubo una diferencia obvia en la efectividad entre el sexo del perro o entre los perros colocados en granjas comunales o ranchos comerciales. La mayoría de los perros mostraron problemas de comportamiento en alguna etapa, particularmente en el juego de persecución, su permanencia en casa u hostigando al ganado, pero el entrenamiento correctivo resolvió el 61% de los problemas reportados. Concluimos que, con el entrenamiento y cuidado correctos, los perros guardianes del ganado pueden ser un método efectivo de protección del ganado en las granjas de Namibia.

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¹: This research was supported by the Agricultural Commissioner of Los Angeles County Contract No. S 51533 and PHS Grant 2 R01-NS11618.

²: This research was performed in partial fulfillment of the requirements for the Master of Arts degree.

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Brief reportConditioned taste aversion: A field application to coyote predation on sheep1

Behav. Biol.

Behav. Biol.

Assessment of sheep losses

Brief report
Conditioned taste aversion: A field application to coyote predation on sheep1