Investigations into the causes of variation in the vocalisations of captive black and gold howler monkeys
Investigations into the causes of variation in the vocalisations of captive black and gold howler monkeys (Alouatta caraya) and their influence on welfare
This study aimed to determine the function of howl vocalisations performed by the black and gold howler monkey, (Alouatta caraya), and to examine the connections between howling, welfare and breeding in captivity.
Comparisons of the behaviours performed during natural howling bouts and during howling bouts in response to experimental playbacks provided evidence for a range of howl functions including territorial defence, advertisement of the caller’s location and mate defence and attraction.
Detailed analyses of howl call acoustics provided the first evidence of both individuality and context-specificity in the calls of A. caraya males, further supporting the functions of mate defence and selection and suggesting that howling may act as an honest signal of male quality. Experimental playbacks of conspecific calls were suggested as an effective form of environmental enrichment; however, the efficacy of conspecific call playbacks were not reflected in the opinions of A. caraya keepers surveyed.
Analysis of the European studbook found that individuals housed in a family group rather than a pair and those which are regularly exposed to the calls of conspecific males, had higher reproductive success. Also, males who performed higher rates of howling had higher reproductive success providing the first evidence of a link between howling and breeding rates.
From these findings it is recommended that captive A. caraya be housed in social groups containing more than one male and one female and that the playback of conspecific male howl calls be introduced into the husbandry of groups to provide a more naturalistic auditory environment.
Paignton Zoo Environmental Park
COMMENDATION received in BIAZA Awards 2011 for Best research project