Dog barks influence the physiological stress and behavior of a wild primate

• Published in: The Science of the total environment 2023-07, Vol.882, p.163585-163585, Article 163585
• Main Authors: Rangel-Negrín, Ariadna, Gómez-Espinosa, Eugenia Eréndira, Chavira-Ramírez, David Roberto, Dias, Pedro A.D.
• Format: Article
• Language: English
• Subjects: adults; Alouatta; Alouatta - metabolism; Alouatta palliata; Animals; Canis; Dogs; Ecosystem; environment; flight; Glucocorticoids; habitats; Howler monkeys; Male; metabolites; Mexico; Playbacks; Primates; stress response; Stress, Physiological
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.163585

Non-lethal impacts of dogs on primates have seldom been assessed. We used an experimental approach to determine if mantled howler monkeys (Alouatta palliata) perceive dog barks as an aversive stimulus and thus display physiological and behavioral responses toward simulated barks. For one year (1754 h of observations) we studied 16 adult males belonging to five groups in Los Tuxtlas (Mexico), and recorded the occurrence of naturally occurring dog barks, their sound pressure level (SPL), and the behavioral responses of howler monkeys to barks. We then exposed males to bark playbacks at two SPL treatments, 40 and 80 dB in a total of 50 experiments. We assayed glucocorticoid metabolite concentrations in fecal samples (fGCM) as a marker of the physiological stress response of males. We also recorded the duration of vigilance, vocalizations, and flight in relation to playbacks. Naturally occurring barks were frequent and usually elicited behavioral responses by males. fGCM concentrations increased after bark playbacks and with stimuli intensity. Time spent vigilant increased following playbacks independently of stimuli intensity but both vocalizations and flight were linked to stimuli intensity: vocalizations were the longest after barks played-back at 80 dB, but males spent more time fleeing in response to 40 dB bark playbacks. These results provide evidence that dog barks are pervasive in the habitat of mantled howler monkeys living at Los Tuxtlas and disturb males, both physiologically and behaviorally. Although the potential costs of physiological and behavioral responses could not be determined, there is sufficient evidence to assume that they do have negative impacts on individuals. Therefore, our study provides avenues for future research on dog-wildlife interactions and valuable information for the design of conservation actions aimed at mitigating the impact of dogs on mantled howler monkeys. [Display omitted] •The effects of dog disturbance on primates have seldom been assessed.•We used playback experiments to examine the impact of barks on mantled howler monkey physiology and behavior.•Physiological stress increased with dog bark intensity and behavioral responses were variable.•Dog barks disturb mantled howler monkeys, both physiologically and behaviorally.