Featured Research

from universities, journals, and other organizations

Black, white and stinky: Explaining bold coloration in skunks

Date:
June 8, 2011
Source:
University of Massachusetts Amherst
Summary:
Biologists can now explain why some species such as skunks use bold coloration to warn predators either that they risk being sprayed with stinky gas or getting into a vicious fight, while other species don't.

Skunk. Evolutionary biologists have now explained why some species such as skunks use bold coloration to warn predators either that they risk being sprayed with stinky gas or getting into a vicious fight, while other species don't.
Credit: Dan Dzursin

In a first-of-its-kind analysis of the evolution of warning coloration in carnivores recently published by University of Massachusetts Amherst evolutionary biologist Ted Stankowich and colleagues, the researchers explain why some species such as skunks use bold coloration to warn predators either that they risk being sprayed with stinky gas or getting into a vicious fight, while other species don't.

Related Articles


Stankowich says most evolutionary research attention to date on warning coloration in animals has been paid to species like newts, poison dart frogs and insects, so this new investigation is a rare comprehensive analysis of mammalian warning coloration, also known as aposematic coloration, such as the skunk's bold stripes.

He adds, "It's important to be clear that bold coloration is not just advertising the ability to spray your anal glands, it's often an advertisement for ferocity. Some of these small black and white animals are extremely ferocious, for example the honey badger."

Stankowich, who is also a visiting postdoctoral and teaching fellow at Harvard, with Tim Caro of the University of California Davis and UMass Amherst undergraduate Matthew Cox, conducted this first systematic examination of the evolutionary drivers of bold coloration patterns and placement in carnivores such as skunks, badgers, civet cats and wolverines.

The researchers collected data on 188 species of mammalian carnivores and found those who are more boldly colored are more likely to be stocky, able to spray noxious chemicals from their anal glands, burrowing, nocturnal and living in exposed environments. Results appear in the current online edition of the journal Evolution.

"One question we're asking is what are the possible evolutionary advantages of bold coloration in mammals," he says. "Why would you want to be so bold, calling more attention to yourself when camouflage is such an effective strategy? We've tested how certain aspects of species ecology and lifestyle might shape the evolution of this phenomenon."

Among the evolutionary advantages these strategies may carry is the ability to move into a new habitat that is relatively exposed to predators but not exploited by other animals or the ability to remain living in a habitat that suddenly experiences an influx of new predators.

To investigate eight factors that are potentially involved in the evolution of aposematic coloration, Stankowich and colleagues categorized 188 carnivore species by pelage: from a single color to extravagantly and boldly marked, which contributes to a feature they call salience, an expression of how well a species stands out in its environment due to its color pattern. Other variables included in the analyses are the ability to spray noxious anal gland secretions, body shape and habitat openness.

The researchers then used a series of statistical steps including phylogenetic independent contrast methods, which are based on information about species' evolutionary relationships, to look at changes in a particular trait. They analyzed these contrast scores with a measure known as Akaike's information criterion (AIC) to obtain the relative goodness of fit for variables to a statistical model. AIC analysis reveals which variables play the strongest role in explaining the variation in the data, Stankowich notes.

In this case, the authors identified the 10 strongest models, then looked at which variables most commonly occurred in those models. These strongest models were used to calculate summary weights for each factor, an indicator of the importance of each predictor. They found that the evolution of boldly colored body patterns was best explained by body length, habitat openness, anal spray ability and burrowing behavior.

They also found that species with horizontal stripes along the body leading to the tail are more likely to be able to spray their anal gland secretions at predators in defense, suggesting that the stripes also direct the predator's attention to the area where the weapon is found. Similarly, a previous study found that facial stripes in this group were found in species that defend themselves by fighting, often with strong bites.

Overall, these anti-predator strategies appear to have evolved independently several times among the Carnivora, say Stankowich and colleagues. So, for example, other nocturnal, slow, stocky, small-to-medium animals with bold black-and-white coloration signaling the presence of noxious anal gland secretions and/or the ability to fiercely defend themselves can be found living in open areas in Africa as well as North and South America and Europe.


Story Source:

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


Journal Reference:

  1. Theodore Stankowich, Tim Caro, Matthew Cox. Bold Coloration and the Evolution of Aposematism in Terrestrial Carnivores. Evolution, 2011; DOI: 10.1111/j.1558-5646.2011.01334.x

Cite This Page:

University of Massachusetts Amherst. "Black, white and stinky: Explaining bold coloration in skunks." ScienceDaily. ScienceDaily, 8 June 2011. <www.sciencedaily.com/releases/2011/06/110607103026.htm>.
University of Massachusetts Amherst. (2011, June 8). Black, white and stinky: Explaining bold coloration in skunks. ScienceDaily. Retrieved December 21, 2014 from www.sciencedaily.com/releases/2011/06/110607103026.htm
University of Massachusetts Amherst. "Black, white and stinky: Explaining bold coloration in skunks." ScienceDaily. www.sciencedaily.com/releases/2011/06/110607103026.htm (accessed December 21, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Sunday, December 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
Monarch Butterflies Descend Upon Mexican Forest During Annual Migration

Monarch Butterflies Descend Upon Mexican Forest During Annual Migration

Reuters - Light News Video Online (Dec. 19, 2014) Millions of monarch butterflies begin to descend onto Mexico as part of their annual migration south. Rough Cut (no reporter narration) Video provided by Reuters
Powered by NewsLook.com
The Best Protein-Filled Foods to Energize You for the New Year

The Best Protein-Filled Foods to Energize You for the New Year

Buzz60 (Dec. 19, 2014) The new year is coming and nothing will energize you more for 2015 than protein-filled foods. Fitness and nutrition expert John Basedow (@JohnBasedow) gives his favorite high protein foods that will help you build muscle, lose fat and have endless energy. Video provided by Buzz60
Powered by NewsLook.com
Birds Might Be Better Meteorologists Than Us

Birds Might Be Better Meteorologists Than Us

Newsy (Dec. 19, 2014) A new study suggests a certain type of bird was able to sense a tornado outbreak that moved through the U.S. a day before it hit. 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:

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