Results 141 to 150 of about 3,913 (178)

Vigilance and aggregation in black howler monkeys ( Alouatta pigra )

Behavioral Ecology and Sociobiology, 2001
Animals are expected to reduce per capita vigilance with increasing group size. Widespread support for this expectation has been found in studies of birds and ungulates. Primate vigilance patterns appear to differ, but studies of primates may have sampled groups with too many members to detect intergroup differences in vigilance. We tested this idea by
Adrian Treves, Ann Drescher, Nicky Ingrisano   +2 more
openaire   +1 more source

Social modulation of testosterone levels in male black howlers (Alouatta pigra)

Hormones and Behavior, 2011
The influence of social factors on the modulation of male testosterone levels has been demonstrated among several vertebrate species. In addition to sexual activity, parental care and reproductive competition affect testosterone secretion. We examined variations in testosterone levels among male black howlers (Alouatta pigra) in various social contexts.
Ariadna, Rangel-Negrín, Pedro A D, Dias, Roberto, Chavira, Domingo, Canales-Espinosa   +3 more
openaire   +2 more sources

Factors affecting the drinking behavior of black howler monkeys (Alouatta pigra)

Primates, 2013
Water is essential for animals, and is particularly critical for thermoregulation. Animals obtain water from three main sources, free water, water contained in food, and water produced in the body during metabolism. Howler monkeys (Alouatta spp.) spend a small proportion of their time drinking water and some populations have not been observed drinking,
Pedro Américo D, Dias, Ariadna, Rangel-Negrín, Alejandro, Coyohua-Fuentes, Domingo, Canales-Espinosa   +3 more
openaire   +2 more sources

Genetic diversity in black howler monkeys (Alouatta pigra) from Belize

American Journal of Physical Anthropology, 1997
To assess the level of genetic variation in a threatened black howler monkey (Alouatta pigra) population, we examined 36 allozyme loci and restriction fragment profiles of mitochondrial DNA (mtDNA). Mean heterozygosity at allozyme loci was only 0.021 and 5.6 percent of the loci were polymorphic.
R A, James, P L, Leberg, J M, Quattro, R C, Vrijenhoek   +3 more
openaire   +2 more sources

Population Reduction and Social Disorganization in Alouatta pigra Following a Hurricane

International Journal of Primatology, 2003
The opportunity to study the effects of a powerful hurricane on monkey populations, diet, and behavior via pre- and post-hurricane data was presented when hurricane Iris virtually destroyed the forest along Monkey River in southern Belize on October 8, 2001, including a 52-ha area where black howlers have been subjects since 1999. Before the hurricane,
Mary S. M. Pavelka, Olivia T. Brusselers, Dana Nowak, Alison M. Behie   +3 more
openaire   +1 more source

Geographical distribution of the black howler (Alouatta pigra) in Central America

Primates, 1986
The geographic range of the black howler,Alouatta pigra in Mexico, Guatemala, and Belize was investigated by travelling through and visiting 65 locations within or close to the expected range. The existence of the species was noted through first hand observations or was documented by talking with residents and knowledgeable people in the area ...
Robert H. Horwich, Edwin D. Johnson
openaire   +1 more source

Roaring rhythms in black howler monkeys (Alouatta pigra) of Belize

Primates, 1983
Roaring was recorded during 15-min intervals for 55 days from April 29 to July 14, 1981 in the area around Bermuda Landing, Belize. Roaring profiles were compiled to represent four three-week periods in which roaring was graphed against the time of day. Rates of roaring were also calculated for three troops.
Robert H. Horwich, Kris Gebhard
openaire   +1 more source

FIELD TECHNIQUES FOR VASECTOMY IN BLACK HOWLER MONKEYS (ALOUATTA PIGRA)

Journal of Zoo and Wildlife Medicine
Three adult black howler monkeys (Alouatta pigra) were vasectomized for the purpose of population control. Two different surgical approaches (inguinal and pelvic) were used to vasectomize the animals under general anesthesia. One monkey was vasectomized with a pelvic approach, and the other two monkeys were vasectomized with an inguinal approach.
Samantha C, Rummel, Andrew C, Cushing, Christopher K, Smith, Pablo Jarrín, Yépez, Deborah, Haines   +4 more
openaire   +2 more sources

Determination of Fecal Glucocorticoid Metabolites to Evaluate Stress Response in Alouatta pigra

International Journal of Primatology, 2008
Measuring fecal glucocorticoid metabolites is now a common practice to assess the stress response in primates. Nevertheless, it is important to validate the utilized immunoassay for each primate species before the technique is applied to populations in the wild.
Rodolfo Martínez-Mota, Rupert Palme, Carolina Valdespino   +2 more
exaly   +2 more sources

Demographic Features of Alouatta pigra Populations in Extensive and Fragmented Forests

2006
Until now, little information was known about demographic features of the regionally endemic black howler populations living in large tracks of tropical forests. Here, we report results from population surveys conducted in eight extensive forests sites (>8.5 km2) in Mexico and Guatemala.
Sarie Van Belle, Alejandro Estrada
openaire   +1 more source