Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Bigger gorillas better at attracting mates and raising young

02.05.2012
Study in Congo protected area helps researchers understand selective factors in gorilla behavior and reproduction

Conservationists with the Wildlife Conservation Society and the Max Planck Institute for Evolutionary Anthropology have found that larger male gorillas living in the rainforests of Congo seem to be more successful than smaller ones at attracting mates and even raising young.


This is an adult male gorilla -- also known as a "silverback" (far right) -- with a family group in Nouabalé-Ndoki National Park in the Republic of Congo. Conservationists from WCS and the Max Planck Institute for Evolutionary Anthropology recently discovered that larger male gorillas are more successful than smaller ones at attracting mates and raising young.
Credit: Thomas Breuer/WCS

The study—conducted over a 12-year period in Nouabalé-Ndoki National Park in the Republic of Congo—helps to illuminate the selective pressures that influence the evolution of great apes.

The study appears in a recent edition of Journal of Human Evolution. The authors of the study include: Thomas Breuer of the Wildlife Conservation Society and the Max Planck Institute for Evolutionary Anthropology; and Andrew M. Robbins, Christophe Boesch, and Martha M. Robbins of the Max Planck Institute for Evolutionary Anthropology.

In assessing the role of size in the reproductive success of "silverback" gorillas, the researchers selected three physical factors for measurement: overall body length; the size of the adult male's head crest (also known as a sagittal crest which is absent in females); and the size of an individual's gluteal muscles on the animal's posterior. The researchers then compared data on individual size with information on group dynamics to explore possible correlations between physical characteristics of adult males, the number of female gorillas connected to males, and the survival rates of an adult gorilla's offspring.

The results of the study revealed that all three characteristics were positively correlated to an adult male's average number of mates. In other words, the bigger the adult male, the more mates it had. An unexpected finding was that only head-crest size and gluteal muscles were strongly related to offspring survival (measured as infants that survived to weaning age) and overall reproductive success, measured as the number of surviving offspring.

"Our findings of correlations between physical traits and male reproductive success could be considered evidence of a selection process in gorillas, but it is not yet proof," said Breuer, the lead author of the study. "More studies would be necessary to determine the links between morphology and fitness in this and other long-lived species."

The research is the latest of several studies of gorillas made from the ideal research conditions of Nouabalé-Ndoki National Park's Mbeli Bai, a large, swampy forest clearing where gorillas (and scientists studying them) gather for long periods. From 1995 until 2007, the team followed the lives of 19 adult male western lowland gorillas and their family groups from observation platforms with telescopes and cameras. Over that time, the researchers were able to track the number of females each male mated with, and the number and survival rate of offspring produced by each adult male.

The gorilla group data was complemented by physical measurements of adult male gorillas by using a novel, non-invasive method called digital photogrammetry, which produces accurate measurements of individual gorillas and their characteristics from digital images (converting pixel size to actual lengths).

"By using non-invasive methods for measuring the size of individual male gorillas and their features, we are gaining insights about the factors that could be driving mate selection in our closest relatives," added Breuer.

"Studies such as these—ones that examine the subtle dynamics of gorilla interactions—are only possible in the stable conditions created in protected areas such as Nouabalé-Ndoki National Park," said Dr. James Deutsch, Executive Director for WCS's Africa Program.

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 & Busch Gardens Conservation Fund, The Toronto Zoo, the Wildlife Conservation Society, and The Woodland Park Zoo.

John Delaney | EurekAlert!
Further information:
http://www.wcs.org

More articles from Ecology, The Environment and Conservation:

nachricht Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

nachricht Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Stiffness matters

22.02.2018 | Life Sciences

Magnetic field traces gas and dust swirling around supermassive black hole

22.02.2018 | Physics and Astronomy

First evidence of surprising ocean warming around Galápagos corals

22.02.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>