Population trends of the mantled howler groups of La Pacifica, Guanacaste, Costa Rica

Abstract

A complete survey of La Pacifica in Guanacaste Province, Costa Rica was conducted in July 1984 in order to determine whether the howler (Alouatta palliata) population had declined since 1972 as a result of deforestation. During the 6-day survey, 257 howlers were located, representing 16 different social groupings and nine solitary animals. The total number of howlers, the number and location of groups, and the age-sex composition were very similar to a 1972-1976 survey of the same population. Age-sex composition of La Pacifica howler groups was similar to those of another population of mantled howlers in Costa Rica and of populations in Mexico and in Panama, although La Pacifica had a higher mean number of adult females per group. There was no evidence to support the hypothesis that the La Pacifica howler population has declined in recent times.

Alouatta caraya: Population density and demography in Northern Argentina

“…ratio below 1:1.5. Further censuses by Clarke et al [1986] showed that this population kept its density and structure for more than a decade despite a "distressed" picture. If Heltne et al's "11 year model" is used instead, La Pacifica's and also the long-term stable Santa Rosa's howler populations fit the predicted female to immature ratios [Fedigan, 19861.…”

Molecular systematics and biogeography of the Neotropical monkey genus, Alouatta

“…For example in some primates females are philopatric and males are polygynous, conditions which would cause greater phylogeographic structuring of matrilines and changes in the relative coalescent times of mtDNA and nuclear genes that could lead to disagreement between markers regarding evolutionary relationships among populations or species (Hoelzer, 1997). However, both sexes disperse in howler monkeys (Brockett et al, 2000;Clarke et al, 1986;Crockett and Eisenberg, 1987;Crockett and Pope, 1993;Glander, 1992;Pope, 2000;Ostro et al, 2001) and although typically perceived to be polygynous, polyandry has been demonstrated for A. palliata (Cort e es-Ortiz, 1998; Jones and Cort e es-Ortiz, 1998; see also Carpenter, 1934). If polygyny predominates in howler societies, the lack of species-specific allele coalescence in the RAG1 and CAL trees becomes even more surprising.…”

Behavioral Development and Socialization of Infants in a Free-Ranging Group of Howling Monkeys (Alouatta palliata)

“…Howling monkeys are found in all of the forested areas. A more complete description of the farm, howler locations, and age-sex composition of howler groups can be found in Clarke et al [29].…”