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 July 28, 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 July 28, 2014).

Share This




More Plants & Animals News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com
Raw: Sea Turtle Hatchlings Emerge from Nest

Raw: Sea Turtle Hatchlings Emerge from Nest

AP (July 27, 2014) A live-streaming webcam catches loggerhead sea turtle hatchlings emerging from a nest in the Florida Keys. (July 27) Video provided by AP
Powered by NewsLook.com
Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Newsy (July 27, 2014) The satellite is back under ground control after a tense few days, but with a gecko sex experiment on board, the media just couldn't help themselves. Video provided by Newsy
Powered by NewsLook.com
Trees Could Save More Than 850 Lives Each Year

Trees Could Save More Than 850 Lives Each Year

Newsy (July 27, 2014) A national study conducted by the USDA Forest Service found that trees collectively save more than 850 lives on an annual basis. Video provided by Newsy
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:
from the past week

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