Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Orang-utan females prefer cheek-padded males

02.09.2015

Dominant, cheek-padded orang-utan males are significantly more successful at fathering offspring – except in times of rank instability

Unlike most mammals, male orang-utans express one of two distinct morphological forms: some develop large “cheek pads” on their faces; others do not. A team of researchers led by Graham L. Banes and Linda Vigilant of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, studied the reproductive success of Kusasi, the former dominant male at Camp Leakey in Indonesia’s Tanjung Puting National Park and compared it with that of socially subordinate, non-cheek-padded males from the same area.


Subordinate orang-utan male without cheek pads (left) and dominant male with cheek pads (right), Tanjung Puting National Park, Indonesia.

Bpk Bain


Orang-utan mother with offspring, Tanjung Puting National Park, Indonesia.

© Bpk Bain

To this aim the researchers collected faecal samples and performed paternity testing. They found that, during his decade as “king” of the jungle, Kusasi fathered significantly more offspring than any other male. Only during periods of rank instability, in the beginning and at the end of Kusasi’s dominance, did other males succeed in fathering offspring. The findings are published in the journal Behavioral Ecology and Sociobiology.

Typically, only one male orang-utan in any given area – the dominant one – has cheek pads. Along with increased body size and a large, pendulous throat sac – used to bellow resonant 'long call' vocalizations – these cheek pads are characteristic of dominant males, and are suspected to make them more attractive to females, resulting in greater reproductive success compared to non-cheek-padded rivals. But males without cheek-pads are also known to be capable of fathering offspring.

“Dominant males have to find and consume more calories, their movement is restricted as a result of their size, and fights with neighbouring dominant males have been known to result in death”, says Graham L. Banes, a post-doctoral scientist at the Max Planck Institute for Evolutionary Anthropology, who began this longitudinal study at the University of Aberdeen, later moving to the University of Cambridge. “So, why would a male develop cheek pads if he can father offspring without?”

To answer this question, Banes spent eight years studying the orang-utans of Tanjung Puting National Park, twice following their movements for several months at a time from dawn till dusk, collecting faecal samples from all orang-utans observed in the 50 km² study area. The researchers extracted DNA from these samples and identified 39 known individuals, including 12 males.

“We performed paternity testing to see which of these males were fathering offspring at Camp Leakey, and to quantify Kusasi’s reproductive success, compared with that of other, non-cheek-padded males”, says Linda Vigilant of the Max Planck Institute for Evolutionary Anthropology. “Paternity could be assigned to 14 candidate offspring, conceived across multiple decades, ten of which were fathered by Kusasi.”

The results show that Kusasi fathered many more offspring than any other male during his tenure as dominant male, potentially as a result of his cheek pads attracting female orang-utans. As expected, non-cheek-padded males were also shown to have achieved paternities. “The timing, however, was interesting”, says Banes. “These other males were typically reproductively successful at the beginning and end of Kusasi’s dominant period, when the hierarchy was potentially unclear.”

From this, the authors conclude that cheek pad development is an evolutionarily stable strategy: reproductive success is significantly skewed in favour of dominant, cheek-padded males, while other males simply bide their time until periods of rank instability.


Contact

Dr. Graham L. Banes
Max Planck Institute for Evolutionary Anthropology, Leipzig
Phone: +86 131 221-02502

Email: graham_banes@eva.mpg.de


Dr. Linda Vigilant
Max Planck Institute for Evolutionary Anthropology, Leipzig
Phone: +49 341 3550-222

Email: vigilant@eva.mpg.de


Sandra Jacob
Press and Public Relations

Max Planck Institute for Evolutionary Anthropology, Leipzig
Phone: +49 341 3550-122

Fax: +49 341 3550-119

Email: info@eva.mpg.de


Original publication
Graham L. Banes, Biruté M. F. Galdikas & Linda Vigilant

Male orang-utan bimaturism and reproductive success at Camp Leakey in Tanjung Puting National Park, Indonesia

Behavioral Ecology and Sociobiology, 01.09.2015, DOI: 10.1007/s00265-015-1991-0

Dr. Graham L. Banes | Max Planck Institute for Evolutionary Anthropology, Leipzig

More articles from Life Sciences:

nachricht Scientists call for improved technologies to save imperiled California salmon
14.12.2017 | NOAA Fisheries West Coast Region

nachricht Cardiolinc™: an NPO to personalize treatment for cardiovascular disease patients
14.12.2017 | Luxembourg Institute of Health

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Protein Structure Could Unlock New Treatments for Cystic Fibrosis

14.12.2017 | Life Sciences

Cardiolinc™: an NPO to personalize treatment for cardiovascular disease patients

14.12.2017 | Life Sciences

ASU scientists develop new, rapid pipeline for antimicrobials

14.12.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>