Featured Research

from universities, journals, and other organizations

Eye size determined by maximum running speed in mammals

Date:
May 2, 2012
Source:
University of Texas at Austin
Summary:
Maximum running speed is the most important variable influencing mammalian eye size other than body size, according to new research.

Cheetah.
Credit: ian howard / Fotolia

Maximum running speed is the most important variable influencing mammalian eye size other than body size, according to new research from The University of Texas at Austin.

Species with larger eyes usually have higher visual acuity, says Chris Kirk, associate professor in the Department of Anthropology. But what are the ecological factors that cause some mammals to develop larger eyes than others?

"If you can think of mammals that are fast like a cheetah or horse, you can almost guarantee they've got really big eyes," says Kirk. "This gives them better vision to avoid colliding with obstacles in their environment when they're moving very quickly."

Kirk and physical anthropology doctoral student Amber Heard-Booth are the first to apply Leuckart's Law -- a hypothesis that was developed specifically for birds and speed of flight -- to 50 species of mammals. The paper is forthcoming in the journal Anatomical Record. Heard-Booth presented the findings at the 2011 American Association of Physical Anthropology Meeting, where she was awarded the Mildred Trotter Prize for exceptional graduate research in evolutionary morphology.

Previously it was thought that the time of day that an animal is active (nocturnal or diurnal) would be the main factor driving the evolution of mammalian eye size. However, comparative research on the anatomy of the eye has shown that although nocturnal and diurnal species differ in eye shape, they often have similar eye sizes. Although nocturnal species may appear to have bigger eyes because more of the cornea is exposed to let in more light, activity pattern only has a modest effect on eye size.

By comparison, body mass plus maximum running speed together can explain 89 percent of the variation in eye size among mammals.

The researchers controlled for body size and evolutionary relationships, and found that the relationship between eye diameter and maximum running speed is stronger than the relationship between body mass and running speed.

"You start looking at comparative data and one thing that is always going to influence eye size is body size. An elephant is always going to have bigger eyes than a mouse," Kirk says. "Elephants are the biggest animals we measured, but they are not that fast compared to a cheetah or zebra. At the same time, porcupines -- the biggest of the rodents in our sample -- are slow while some smaller rodents are much faster.

"There is going to be the effect of body mass, but when you look at maximum running speed in isolation or when you hold body mass constant, it's still significantly related to eye size," Kirk says. "And when you combine maximum running speed and body mass as your two variables influencing how big an eye is, they can explain almost all of the differences observed between species. This is a highly significant result."


Story Source:

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


Journal Reference:

  1. Amber N. Heard-Booth, E. Christopher Kirk. The Influence of Maximum Running Speed on Eye Size: A Test of Leuckart's Law in Mammals. The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology, 2012; DOI: 10.1002/ar.22480

Cite This Page:

University of Texas at Austin. "Eye size determined by maximum running speed in mammals." ScienceDaily. ScienceDaily, 2 May 2012. <www.sciencedaily.com/releases/2012/05/120502112606.htm>.
University of Texas at Austin. (2012, May 2). Eye size determined by maximum running speed in mammals. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2012/05/120502112606.htm
University of Texas at Austin. "Eye size determined by maximum running speed in mammals." ScienceDaily. www.sciencedaily.com/releases/2012/05/120502112606.htm (accessed October 20, 2014).

Share This



More Plants & Animals News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

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
Adorable Video of Baby Rhino and Lamb Friend Playing

Adorable Video of Baby Rhino and Lamb Friend Playing

Buzz60 (Oct. 20, 2014) Gertjie the Rhino and Lammie the Lamb are teaching the world about animal conservation and friendship. TC Newman (@PurpleTCNewman) has the adorable video! 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