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Conservationists with the Wildlife Conservation Society and the MaxPlanck Institute for Evolutionary Anthropology have found thatlarger male gorillas living in the rainforests of Congo seem to bemore successful than smaller ones at attracting mates and evenraising young. The study-conducted over a 12-year period in Nouabale-NdokiNational Park in the Republic of Congo-helps to illuminate theselective pressures that influence the evolution of great apes. The study appears in a recent edition of Journal of HumanEvolution. The authors of the study include: Thomas Breuer of theWildlife Conservation Society and the Max Planck Institute forEvolutionary Anthropology; and Andrew M. Robbins, ChristopheBoesch, and Martha M. Robbins of the Max Planck Institute forEvolutionary Anthropology. In assessing the role of size in the reproductive success of"silverback" gorillas, the researchers selected three physicalfactors for measurement: overall body length; the size of the adultmale's head crest (also known as a sagittal crest which is absentin females); and the size of an individual's gluteal muscles on theanimal's posterior. The researchers then compared data on individual size withinformation on group dynamics to explore possible correlationsbetween physical characteristics of adult males, the number offemale gorillas connected to males, and the survival rates of anadult gorilla's offspring. The results of the study revealed that all three characteristicswere positively correlated to an adult male's average number ofmates. In other words, the bigger the adult male, the more mates ithad. An unexpected finding was that only head-crest size and glutealmuscles were strongly related to offspring survival (measured asinfants that survived to weaning age) and overall reproductivesuccess, measured as the number of surviving offspring. "Our findings of correlations between physical traits and malereproductive success could be considered evidence of a selectionprocess in gorillas, but it is not yet proof," said Breuer, thelead author of the study. "More studies would be necessary todetermine the links between morphology and fitness in this andother long-lived species." The research is the latest of several studies of gorillas made fromthe ideal research conditions of Nouabale-Ndoki National Park'sMbeli Bai, a large, swampy forest clearing where gorillas (andscientists studying them) gather for long periods. From 1995 until 2007, the team followed the lives of 19 adult malewestern lowland gorillas and their family groups from observationplatforms with telescopes and cameras. Over that time, theresearchers were able to track the number of females each malemated with, and the number and survival rate of offspring producedby each adult male. The gorilla group data was complemented by physical measurements ofadult male gorillas by using a novel, non-invasive method calleddigital photogrammetry, which produces accurate measurements ofindividual gorillas and their characteristics from digital images(converting pixel size to actual lengths). "By using non-invasive methods for measuring the size of individualmale gorillas and their features, we are gaining insights about thefactors that could be driving mate selection in our closestrelatives," added Breuer. "Studies such as these-ones that examine the subtle dynamics ofgorilla interactions-are only possible in the stable conditionscreated in protected areas such as Nouabale-Ndoki National Park,"said Dr. James Deutsch, Executive Director for WCS's AfricaProgram. This study was made possible through funding from the Brevard Zoo,Columbus Zoo and Aquarium, Cincinnati Zoo and Botanical Garden,Cleveland Zoological Society, Disney Worldwide Conservation Fund,Dublin Zoo, SeaWorld and Busch Gardens Conservation Fund, TheToronto Zoo, the Wildlife Conservation Society, and The WoodlandPark Zoo. We are high quality suppliers, our products such as Clear Plastic Jars , China Micro Glass Beads for oversee buyer. To know more, please visits Nail Glitter Powder.
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