Nav: Home

Study: Infamous 'death roll' almost universal among crocodile species

April 18, 2019

The iconic "death roll" of alligators and crocodiles may be more common among species than previously believed, according to a new study published in Ethology, Ecology & Evolution and coauthored by a researcher at the University of Tennessee, Knoxville.

Contrary to popular belief, crocodiles can't chew, so they use a powerful bite coupled with a full-bodied twisting motion--a death roll--to disable, kill, and dismember prey into smaller pieces. The lethal movement is characteristic of both alligators and crocodiles and has been featured in numerous movies and nature documentaries.

Until now, the death roll had only been documented in a few of the 25 living crocodilian species, but how many actually do it?

"We conducted tests in all 25 species, and 24 of them exhibited the behavior," said lead author Stephanie Drumheller-Horton, a paleontologist and adjunct assistant professor in the Department of Earth and Planetary Sciences at UT.

For the research, Drumheller-Horton teamed up with Kent Vliet from the University of Florida and Jim Darlington, curator of reptiles at the St. Augustine Alligator Farm.

It was previously believed that slender-snouted species, like the Indian gharial, didn't roll because their diets consist of small prey like fish, eaten whole.

But it turns out that feeding isn't the only time the animals might roll.

"Aggression between individual crocodylians can become quite intense, often involving bites and death rolls in establishing dominance or competition for females," Vliet said.

Paleosuchus palpebrosus, commonly called Cuvier's dwarf caiman, is the only species that did not perform a death roll under experimental conditions. "Although, it's also possible that they were just being uncooperative," said Darlington.

And the fossil ancestors of modern crocodiles? If they share a similar body plan and lifestyle with their modern counterparts, it's likely that they could death roll, too.

"Crocodile relatives have played the role of semi-aquatic ambush predator since the Age of Dinosaurs," said Drumheller-Horton.

Whether in the Northern Territories of Australia, a lake in the Serengeti, or a watering hole in the late Cretaceous, chances are that a patient predator is waiting in the water to surprise its next meal with a burst of speed, a powerful bite, and a spinning finish.
-end-
CONTACT:

Andrea Schneibel (865-974-3993, andrea.schneibel@utk.edu)

University of Tennessee at Knoxville

Related Crocodiles Articles:

Synchrotron X-ray sheds light on some of the world's oldest dinosaur eggs
An international team of scientists led by the University of the Witwatersrand in South Africa, has been able to reconstruct, in the smallest details, the skulls of some of the world's oldest known dinosaur embryos in 3D, using powerful and non-destructive synchrotron techniques at the ESRF, the European Synchrotron in France.
Water pressure: Ancient aquatic crocs evolved, enlarged to avoid freezing
Ancient crocodilian ancestors that abandoned land for water nearly 200 million years ago supposedly got larger because they were released from the constraints of gravity, territory and diet.
Crocs' better parenting skills could make them more resilient to climate change
The ability of crocodiles to survive mass extinctions could be in part due to their more hands-on approach to parenting, say scientists at the University of Bath's Milner Centre for Evolution.
Neutron source enables a look inside dino eggs
Did the chicks of dinosaurs from the group oviraptorid hatch from their eggs at the same time?
What did ancient crocodiles eat? Study says as much as a snout can grab
To study the diet of ancient crocodiles, two researchers--one from the University of Tennessee, Knoxville, and one from Stony Brook University--combined mathematical analyses of the animals' shapes, surveys of modern crocodiles' diet, modeling methods for reconstructing the diet of fossil groups, and forensic-style interpretations of damaged bones from the distant past.
New species of crocodile discovered in museum collections
By looking at 90-year-old crocodile skulls in museum collections and double-checking with live specimens at a zoological park in Florida, researchers have just discovered a new species of ten-foot-long croc.
T. rex used a stiff skull to eat its prey
A Tyrannosaurus rex could bite hard enough to shatter the bones of its prey.
Mysterious Jurassic crocodile identified 250 years after fossil find
A prehistoric crocodile that lived around 180 million years ago has been identified -- almost 250 years after the discovery of it fossil remains.
No teeth cleaning needed: Crocodiles shed old teeth, grow new ones
Having one of the most powerful bites in the animal kingdom, crocodiles must be able to bite hard to eat their food such as turtles, wildebeest and other large prey.
Holy crocodiles
Sebastian Brackhane of the University of Freiburg has researched the cultural status of the reptiles in East Timor.
More Crocodiles News and Crocodiles Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Making Amends
What makes a true apology? What does it mean to make amends for past mistakes? This hour, TED speakers explore how repairing the wrongs of the past is the first step toward healing for the future. Guests include historian and preservationist Brent Leggs, law professor Martha Minow, librarian Dawn Wacek, and playwright V (formerly Eve Ensler).
Now Playing: Science for the People

#566 Is Your Gut Leaking?
This week we're busting the human gut wide open with Dr. Alessio Fasano from the Center for Celiac Research and Treatment at Massachusetts General Hospital. Join host Anika Hazra for our discussion separating fact from fiction on the controversial topic of leaky gut syndrome. We cover everything from what causes a leaky gut to interpreting the results of a gut microbiome test! Related links: Center for Celiac Research and Treatment website and their YouTube channel
Now Playing: Radiolab

The Flag and the Fury
How do you actually make change in the world? For 126 years, Mississippi has had the Confederate battle flag on their state flag, and they were the last state in the nation where that emblem remained "officially" flying.  A few days ago, that flag came down. A few days before that, it coming down would have seemed impossible. We dive into the story behind this de-flagging: a journey involving a clash of histories, designs, families, and even cheerleading. This show is a collaboration with OSM Audio. Kiese Laymon's memoir Heavy is here. And the Hospitality Flag webpage is here.