Featured Research

from universities, journals, and other organizations

Female Chimps Keep The Bullies At Bay

Date:
March 8, 2007
Source:
Springer
Summary:
Female chimpanzees may have found a fool-proof way to ensure they mate with only the highest ranking males, namely those with important social and physical characteristics that their offspring may inherit, according to a new study. Female chimpanzees do not synchronize their reproductive activities which reduces the opportunities for less-desirable males to coerce them into mating. The findings have just been published online in Springer's journal Behavioral Ecology and Sociobiology.

Female chimpanzees may have found a fool-proof way to ensure they mate with only the highest ranking males, namely those with important social and physical characteristics that their offspring may inherit, according to a new study1 by Akiko Matsumoto-Oda from the Department of Welfare and Culture at Okinawa University in Japan. Female chimpanzees do not synchronize their reproductive activities which reduces the opportunities for less-desirable males to coerce them into mating. The findings have just been published online in Springer’s journal Behavioral Ecology and Sociobiology.

Most studies of primates to date have suggested that females synchronize their reproductive activities. However, it has been very difficult to demonstrate this analytically. Matsumoto-Oda and colleagues have developed a new index – the estrus synchrony index* - to analyze whether female chimpanzees, in the Mahale Mountains National Park in Tanzania, synchronize the fertile period of their reproductive cycles.**

The authors identified estrus in females by the size of their anogenital swellings, which is related to increased levels of follicular estrogen. The period of maximal swelling was regarded as the ‘estrous period’ because almost all copulations were observed in this phase. In the analysis of the data covering nine years of observations, the authors looked at whether or not females displayed a significant tendency to synchronize their estrous cycles.

Commenting on these findings, the authors suggest that “avoiding synchronizing estrous cycles may be a female strategy to reduce male sexual coercion.”

Indeed, male chimpanzees use coercive tactics such as physical aggression against females, forced copulation, harassment and intimidation to increase their reproductive success. The opportunity for males to coerce females is reduced when females avoid synchronizing their estrous cycles, because with fewer females in estrous at the same time, mating competition between males intensifies. As a result, there is an increased probability that high-ranking males, with desirable social and physical attributes, will mate with the fertile females. These sought-after characteristics could be inherited by their offspring.

* The estrus synchrony index (ESI) is the variance in the proportion of females with maximal swellings to cycling females observed per day. ESI values are large when females synchronize their estrous cycles and are small when they avoid synchronizing.

** The tendency of individuals to undergo the fertile period of the sexual cycle at the same time as other members of the population is known as estrous synchrony.


Story Source:

The above story is based on materials provided by Springer. Note: Materials may be edited for content and length.


Cite This Page:

Springer. "Female Chimps Keep The Bullies At Bay." ScienceDaily. ScienceDaily, 8 March 2007. <www.sciencedaily.com/releases/2007/03/070307101420.htm>.
Springer. (2007, March 8). Female Chimps Keep The Bullies At Bay. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2007/03/070307101420.htm
Springer. "Female Chimps Keep The Bullies At Bay." ScienceDaily. www.sciencedaily.com/releases/2007/03/070307101420.htm (accessed October 21, 2014).

Share This



More Plants & Animals News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

'Cadaver Dog' Sniffs out Human Remains

'Cadaver Dog' Sniffs out Human Remains

AP (Oct. 21, 2014) Where's a body buried? Buster's nose can often tell you. He's a cadaver dog, specially trained to find human remains and increasingly being used by law enforcement and accepted in courts. These dogs are helping solve even decades-old mysteries. (Oct. 21) Video provided by AP
Powered by NewsLook.com
White Lion Cubs Born in Belgrade Zoo

White Lion Cubs Born in Belgrade Zoo

AFP (Oct. 20, 2014) Two white lion cubs, an extremely rare subspecies of the African lion, were recently born at Belgrade Zoo. They are being bottle fed by zoo keepers after they were rejected by their mother after birth. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
Goliath Spider Will Give You Nightmares

Goliath Spider Will Give You Nightmares

Buzz60 (Oct. 20, 2014) An entomologist stumbled upon a South American Goliath Birdeater. With a name like that, you know it's a terrifying creepy crawler. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins