Featured Research

from universities, journals, and other organizations

Biologist And Physicist Team Up To Study Alligator's 'Death Roll'

Date:
April 3, 2007
Source:
West Chester University Of Pennsylvania
Summary:
Other than on television, few of us have ever seen the spectacular spin (and ghastly consequences) of the crocodilian "death roll." But, in a basement laboratory in the University's Schmucker's Science building, a biologist and physicist have been video taping young alligators spinning with the ferocity of their older, larger cousins in the wild.

In a paper entitled, "Death roll of the alligator: mechanics of twist feeding in water," to be published in the Journal of Experimental Biology, West Chester University biologist Frank Fish and physicist Anthony Nicastro and colleagues Sandra Bostic and John Beneski chronicled the particular spinning movement of juvenile alligators in water after biting into a pliable target.
Credit: Image courtesy of West Chester University Of Pennsylvania

Other than on television, few of us have ever seen the spectacular spin (and ghastly consequences) of the crocodilian “death roll.” But, in a basement laboratory in the University’s Schmucker’s Science building, a biologist and physicist have been video taping young alligators spinning with the ferocity of their older, larger cousins in the wild.

Related Articles


In doing so, the researchers created a mathematical model that provides the first explanation as to how these long thin reptiles are able to spin with such force in the water.

In a paper entitled, “Death roll of the alligator: mechanics of twist feeding in water,” to be published in the Journal of Experimental Biology, West Chester University biologist Frank Fish and physicist Anthony Nicastro and colleagues Sandra Bostic and John Beneski chronicled the particular spinning movement of juvenile alligators in water after biting into a pliable target. Through the use of high-speed videos, the researchers were able to examine the specific mechanics of the spinning maneuver – detailing the movements of body components and measuring their spinning performance.

“The death roll is a behavioral strategy referred to as ‘rotational feeding,’” explains Fish, who along with other colleagues has also studied the mechanic and energetic performance of spinning dolphins.

“Spinning motions are seen in birds, sea lions and humpback whales as well, but these animals use their wings or wing-like flippers to actually roll or bank,” says Fish.

Alligators, on the other hand, tuck in their legs, and in a matter of milliseconds, move their tails to the side, which changes the moment of inertia. Movement of the moment of inertia on the body and on the tail allows the crocodilian to start spinning. The alligator spins faster, much in the same way that figure skaters’ spinning motion speeds up when they bring their arms up or toward their chests.

“ The alligator centralizes its mass and axis of rotation by keeping its legs close to its body. This also effectively reduces drag and enables it to create a faster, more

powerful spin,” says Fish.

“Similarly,” he adds, “ human divers create a central axis as they somersault from a diving board.”

Fish and his colleagues also were able to demonstrate that alligators could not be induced to spin when their tails were restrained, even as they held onto their prey.

Scientists have long known that crocodilians performed the death roll to subdue and dismember large prey that they otherwise could not chew because of their conical, spike-like teeth. “These animals don’t chew their prey,” says Fish. “ So, when they capture a prey that’s exceptionally big, they go into the death roll in order to break it apart.”

Fish and his team not only learned the mechanics involved in this process, but contrary to earlier theories, they found that the capacity to perform the death roll is not limited to larger crocodilians, nor is it a learned behavior.

“The young alligators we have in the lab were collected very early or as eggs, so they did not learn about the death roll from older alligators,” says Fish.

“When we gave them meat and tugged on it, they started producing the death roll immediately on their own.”


Story Source:

The above story is based on materials provided by West Chester University Of Pennsylvania. Note: Materials may be edited for content and length.


Cite This Page:

West Chester University Of Pennsylvania. "Biologist And Physicist Team Up To Study Alligator's 'Death Roll'." ScienceDaily. ScienceDaily, 3 April 2007. <www.sciencedaily.com/releases/2007/03/070326132754.htm>.
West Chester University Of Pennsylvania. (2007, April 3). Biologist And Physicist Team Up To Study Alligator's 'Death Roll'. ScienceDaily. Retrieved April 19, 2015 from www.sciencedaily.com/releases/2007/03/070326132754.htm
West Chester University Of Pennsylvania. "Biologist And Physicist Team Up To Study Alligator's 'Death Roll'." ScienceDaily. www.sciencedaily.com/releases/2007/03/070326132754.htm (accessed April 19, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Sunday, April 19, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Un-Bee-Lievable: Bees on the Loose After Washington Truck Crash

Un-Bee-Lievable: Bees on the Loose After Washington Truck Crash

Reuters - US Online Video (Apr. 17, 2015) A truck carrying honey bees overturns near Lynnwood, Washington, spreading boxes of live bees across the highway. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Our Love Of Puppy Dog Eyes Explained By Science

Our Love Of Puppy Dog Eyes Explained By Science

Newsy (Apr. 17, 2015) Researchers found a spike in oxytocin occurs in both humans and dogs when they gaze into each other&apos;s eyes. Video provided by Newsy
Powered by NewsLook.com
Dog Flu Spreading in Midwestern States

Dog Flu Spreading in Midwestern States

AP (Apr. 17, 2015) Dog flu is spreading in several Midwestern states. Dog daycare centers and veterinary offices are taking precautions. (April 17) Video provided by AP
Powered by NewsLook.com
Raw: Rare Whale Spotted in Gulf of Mexico

Raw: Rare Whale Spotted in Gulf of Mexico

AP (Apr. 17, 2015) Researchers from the E/V Nautilus had quite a surprise Tuesday, when a curious sperm whale swam around their remotely operated vehicle in the Gulf of Mexico. Cameras captured the encounter. (April 17) 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:

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