Visitor‐directed aggression among the Gibraltar macaques

Abstract

Animal parks and exhibits which offer visitors the option of close interaction with the animals displayed have been very successful with some species, including primates. However, there is always an element of risk to the visitor who enters another species' environment and interacts with its members. This risk factor may cause particular concern when the exhibit animal is a nonhuman primate because of the transmission of various zoonoses. The Barbary macaques (Macaca sylvanus) at Queen's Gate, Gibraltar, attract large numbers of tourists who are permitted to feed them. This animal-human contact sometimes results in monkeys biting visitors. Bite frequency data from hospital records for 1980-1989 and direct observations (July 1990-June 1991 form the basis of this study. Biting is a density-dependent phenomenon since monkey-visitor aggression rates increase with visitor numbers. Time of day affects bite rates, more people being bitten in the afternoon-the main visitation time. Likewise, more bites are recorded during summer months when visitor numbers are higher. A tendency towards acclimatization of the monkeys to the very large number of visitors appears after 1985. Rank correlation coefficients between visitor numbers and bites per month fall from 1985 to 1989, reflecting a drop in visitor density response. Analysis of visitor profiles indicates a negative correlation between visitor age and likelihood of being bitten. However, women are bitten significantly more than men. Average age of people bitten also varies between months. Recorded aggression levels are generally low despite no control over animal-visitor interactions, but are much higher than in similar Barbary macaque enclosures in France and Germany. The Gibraltar troop's small home range and high visitor density may explain recorded bite levels. Effective visitor education can significantly lower biting incidence.

The ethnoprimatological approach in primatology

“…Close contact and range overlap between humans and other primates introduce a very real and potentially dangerous situation of disease transmission [Engel et al, 2002;Fa, 1992;Jones-Engel et al, 2008;Wallis & Lee, 1999]. In these cases, humans risk exposure to a number of simian viruses, including simian T-cell lymphotropic viruses, simian retrovirus, simian foamy virus and Herpes B virus in addition to other known infectious agents [Engel et al, 2002;Jones-Engel et al, 2008;Wolfe et al, 2004].…”

Human culture and monkey behavior: assessing the contexts of potential pathogen transmission between macaques and humans

“…The only other similar study for the Gibraltar population was conducted by O' Leary and Fa [1993] (see also Fa [1992]). They examined 3,128 Barbary macaque-human interactions at Apes' Den by macaque age/sex classes between 2 July and 23 August 1991.…”

“…Tourists or nonlocals are distinct from locals in terms of exposure and experience relative to the macaques. Close contact and range overlap between humans and macaques also introduces a very real and potentially dangerous situation of disease transmission [Engel et al, 2002;Fa, 1992;Jones-Engel et al, 2005;Wallis & Lee, 1999]. Humans risk exposure to a number of simian viruses, including simian T cell lymphotropic viruses (STLV), simian retrovirus (SRV), simian foamy virus (SFV), and herpes B virus, in addition to other infectious agents [Engel et al, 2002;Jones-Engel et al, 2005;Wolfe et al, 2004].…”

Effects of Tourists on Barbary Macaques at Gibraltar

“…The influx of visitors to the Rock since the frontier opened in 1985 has increased the exposure of the macaques to tourists. The macaques have acclimatized to people [21], and they no lon ger need to make efforts to obtain food, as numerous tourists offer it. There has been a concomitant change in the macaques' behav iour from an active and aggressive strategy a decade ago to a more sedentary and docile approach.…”