Featured Research

from universities, journals, and other organizations

Extinction Risks High For Social Species Such As The African Wild Dog

Date:
October 24, 2008
Source:
University of Chicago Press Journals
Summary:
Because African wild dogs face bigger competitors like lions, whose larger stomachs handle large irregular meals, the African wild dog evolved a runner's metabolism (lithe, smaller stomachs) and formed large packs. In packs they reduce costs and ensure a regular supply of food. But in packs less than five, they end up in poverty traps, less well fed, less able to have pups, and spiral downward. This study reveals an extinction risk for social species.

African wild dog (Lycaon pictus).
Credit: Peter Ruckstuhl / Image courtesy of Wikimedia Commons

In the world of "cut and thrust," humans try to bank money to obtain financial security, and often form cooperatives to reduce risks and increase gains. Many humans also end up in poverty traps, where because of meager resources and an increasingly high cost of living they find themselves unable to raise their heads above the parapet and "never make it."

Over a 20-year period, Gregory Rasmussen, currently at Lady Margaret Hall Oxford, intensively studied every move of African wild dogs in Zimbabwe to the extent of "living with packs" for periods of up to a month in order to work out how much energy they were spending eating, sleeping, and running. He came to the conclusion that "whilst to date we have seen poverty traps as being something intrinsically human, they are not!"

Nature's currency is energy, and in theory, keeping the cost of living low leaves more in the "piggy bank" for reproduction. However, staying in nature's fast lane isn't easy, and necessitates that evolution comes up with a "business plan" to bank energy (nature's surrogate for wealth!) to survive. In the face of bigger competitors like lions and hyenas, whose larger stomachs cater for irregular meals, and which maximize returns by having low foraging costs, the dogs' evolved a unique plan. Now highly endangered, the African wild dog opted for extreme metabolic adaptations to running, thus ensuring they caught a regular supply of food, and by forming packs, had many runners to reduce capture costs and stomachs to maximize on the returns.

This great strategy, however, has an Achilles heel as packs fewer than five are less effective hunters, and thus have to undertake energetically expensive extra hunts to secure their prey. The results from this study highlighted a weakness in the business plan, for when the financial energetic annual accounts were done, the benefits of having fewer individuals to feed in a smaller packs was outweighed by the greater costs of running. To chase their prey, wild dogs need to be lithe and athletic, a design that ensures their stomachs can't be too big, which in turn limits the amount they can gorge in a sitting: a physical limitation on their gluttony which biologist call "a morphological constraint."

In the same way that Size Zero women can struggle to have children, and bouncing babies, this study highlighted an Achilles heel where energetic poverty translated into reproductive poverty, and a vicious circle whereby small packs have fewer pups, leading to even smaller packs, and driving them into an extinctive vortex.

From a conservation standpoint, these results demonstrate how evolutionary strength gained by sociality can be undermined by an Achilles heel that can push species into extinction. Professor David Macdonald, Director of the Wildlife Conservation Research Unit, known as the WildCRU, which specializes in the science to underpin practical solution to conservation problems, said "This study, unique in its detail, shows the power of energetic theory to enable us to not only understand the evolution of packing power, and facets that dictate the survival of this stunningly beautiful species, but better understand how to conserve other social species of which we are one."


Story Source:

The above story is based on materials provided by University of Chicago Press Journals. Note: Materials may be edited for content and length.


Journal Reference:

  1. Rasmussen et al. Achilles' Heel of Sociality Revealed by Energetic Poverty Trap in Cursorial Hunters.. The American Naturalist, 2008; 172 (4): 508 DOI: 10.1086/590965

Cite This Page:

University of Chicago Press Journals. "Extinction Risks High For Social Species Such As The African Wild Dog." ScienceDaily. ScienceDaily, 24 October 2008. <www.sciencedaily.com/releases/2008/10/081020191536.htm>.
University of Chicago Press Journals. (2008, October 24). Extinction Risks High For Social Species Such As The African Wild Dog. ScienceDaily. Retrieved April 23, 2014 from www.sciencedaily.com/releases/2008/10/081020191536.htm
University of Chicago Press Journals. "Extinction Risks High For Social Species Such As The African Wild Dog." ScienceDaily. www.sciencedaily.com/releases/2008/10/081020191536.htm (accessed April 23, 2014).

Share This



More Plants & Animals News

Wednesday, April 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Leopard Bites Man in India

Raw: Leopard Bites Man in India

AP (Apr. 22, 2014) A leopard caused panic in the city of Chandrapur on Monday when it sprung from the roof of a house and charged at rescue workers. (April 22) Video provided by AP
Powered by NewsLook.com
Iowa College Finds Beauty in Bulldogs

Iowa College Finds Beauty in Bulldogs

AP (Apr. 22, 2014) Drake University hosts 35th annual Beautiful Bulldog Contest. (April 21) Video provided by AP
Powered by NewsLook.com
805-Pound Shark Caught Off The Coast Of Florida

805-Pound Shark Caught Off The Coast Of Florida

Newsy (Apr. 22, 2014) One Florida fisherman caught a 805-pound shark off the coast of Florida earlier this month. Video provided by Newsy
Powered by NewsLook.com
Breakfast Foods Are Getting Pricier

Breakfast Foods Are Getting Pricier

AP (Apr. 21, 2014) Breakfast is now being served with a side of sticker shock. The cost of morning staples like bacon, coffee and orange juice is on the rise because of global supply problems. (April 21) Video provided by AP
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