title: Does Trapping Influence Decision-Making under Ambiguity in White-Lipped Peccary (Tayassu pecari)?
abstract: The white-lipped peccary (Tayassu pecari) is an endangered species whose bold anti-predator behaviour in comparison to related species may increase its vulnerability to hunting and predation. We used a judgement bias test to investigate whether captive peccaries that had recently experienced a trapping event made more 'pessimistic' decisions under ambiguity. If so, this would indicate (i) that the procedure may induce a negative affective state and hence have welfare implications, and (ii) that the species is able to adopt a cautious response style despite its bold phenotype. Eight individuals were trained to 'go' to a baited food bowl when a positive auditory cue (whistle; CS+) was given and to 'no-go' when a negative cue (horn A; CS-) was sounded to avoid a loud sound and empty food bowl. An 'ambiguous' auditory cue (bell; CSA) was presented to probe decision-making under ambiguity. Individuals were subjected to three tests in the order: T1 (control-no trap), T2 (24h after-trap procedure), and T3 (control-no trap). In each test, each animal was exposed to 10 judgement bias trials of each of the three cue types: CS+,CS-,CSA. We recorded whether animals reached the food bowl within 60s ('go' response) and their response speed (m/s). The animals varied in their responses to the CSA cue depending on test type. In all tests, animals made more 'go' responses to CS+ than CSA. During control tests (T1 and T3), the peccaries showed higher proportions of 'go' responses to CSA than to CS-. In T2, however, the animals showed similar proportions of 'go' responses to CSA and CS-, treating the ambiguous cue similarly to the negative cue. There were differences in their response speed according to cue type: peccaries were faster to respond to CS+ than to CS- and CSA. Trapping thus appeared to cause a 'pessimistic' judgement bias in peccaries, which may reflect a negative affective state with implications for the welfare and management of captive individuals, and also function to increase caution and survival chances following such an event in the wild environment.
authors.affiliation: Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil.
authors.forename: Selene Siqueira da Cunha
authors.initials: SS
authors.lastname: Nogueira
authors.affiliation: Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil.
authors.forename: Iurianny Karla
authors.initials: IK
authors.lastname: Fernandes
authors.affiliation: Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil.
authors.forename: Thaise Silva Oliveira
authors.initials: TS
authors.lastname: Costa
authors.affiliation: Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil.
authors.forename: Sérgio Luiz Gama
authors.initials: SL
authors.lastname: Nogueira-Filho
authors.affiliation: University of Bristol, Langford, Bristol, United Kingdom.
authors.forename: Michael
authors.initials: M
authors.lastname: Mendl
mesh_terms: D000818:Animals; D001188:Artiodactyla / Q000502:physiology*; D001522:Behavior, Animal / Q000502:physiology*; D003657:Decision Making; D056727:Endangered Species; D005260:Female; D007600:Judgment / Q000502:physiology; D008297:Male; D011930:Reaction Time