Brief Report Folia PrimatoI1997;68:1O0-1O5 Received: November 21, 1995 Accepted after revision: May 29, 1996 oo oo. Conspecific Aggression and Predation: Costs for a Solitary Mantled Howler Monkey Alfredo D. Cuarón Wildlife Research Group, Department of Anatomy, University of Cambridge, UK Key Words Alouatta palliata . Howler monkey . Solitary individual. Dispersal . Intraspecific aggression . Predation . Jaguar. Panthera anca. Wildlife translocation . Habitat fragmentation . Mexico Introduction Primates may face an increased risk of predation, starvation and conspecific attack during intergroup dispersal [1]. Mortality of male mantled howler monkeys (Alouatta palliata) peaks when they are approaching maturity [2], when dispersal usu- ally takes place [3]. Conspecific aggression accounts for at least some of this mortal- ity [2]: juveniles .i!!~ torced to migrate from natal groups by adults and, while solitary, they are hara"SS'eér'byresident troops and exposed to injury and predation [3, 4]. How- ever, it is often difficult to obtain information on the fate of solitary howler monkeys, given their inconspicuous behaviour. Predation on primates is seldom observed and most reports are anecdotal [5]. In most cases, predation is assumed follo~ing disappearances, sílice actual cases of suc- cessful attacks are difficult to confirm~owler monkeys are known to be preyed upon by harpy eagles (Harpia harpyja) [6-10], jaguars (Panthera anca) [11-13], dogs (Canis familiaris) [M. Galetti, pers. commun.] and probably ocelots (Felis pardalis) [14]. It is also possible that howlers are preyed upon by other felids, large mustelids and snakes [15], but confirmatory data are lacking)All available factual predation accounts relate to the red howler monkey (A. seniculus), the black howler monkey (A. caraya) and the brown howler monkey (A. fusca). Apparently, there are no previ- ous published reports of confirmed predation on A. palliata. Given the patchiness of information, observations on the behaviour and move- meDís of solitary howler monkeys and on predation are il!1Portant in g~Dq~ting further ~ata for testing hypothesis. Here, I report a case in which a solitary subadult male mantled howleimonkey was preyed upon by a jaguar. In this instance, two of the dan- gerous situations that solitary primates risk - intraspecific aggression and predation - occurred in combination. Some observations on the movements and behaviour of soli- tary howlers seeking to reduce conspecific hostility are also presented. KARGER (Q 1997 s, Karger AG, Basel . 0015-5713/97/0682-0100$12,0010 E-Mail karger@karger.ch Fax+41 613061234 http://www,karger.ch Alhedo D, Cuarón, Wildlife Research Group Department of Anatomy, University of Cambridge Downing Street, Cambridge CB2 3DY (UK) Te], +44 1223 333 753, Fax +441223333786 E-Mail adc17@hermes.camac.uk