Infamy & # 39; death & # 39; almost universal among crocodile species

<div data-thumb = "" data-src = " newman / gfx / news / hires / 2019 / studyinfamou.jpg "data-sub-html ="Paleosuchus palpebrosus, also known as Cuvier's dwarf alligator. Credit: Kent Vliet / University of Florida. ">

<img src = "" alt = "Study: infamous & rolled" death almost universal among Crocodile species "title ="Paleosuchus palpebrosus, also known as Cuvier's dwarf alligator. Credit: Kent Vliet / University of Florida. "/>
Paleosuchus palpebrosus, also known as Cuvier's dwarf alligator. Credit: Kent Vliet / University of Florida.

The iconic "release of death" of alligators and crocodiles may be more common among species than previously believed, according to a new study published in Ethology, ecology and evolution. and coauthor of a researcher at the University of Tennessee, Knoxville.

Contrary to popular belief, crocodiles can not chew, so they use a powerful bite combined with a full-body rotating 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 appeared in numerous nature films and documentaries.

So far, the death record has only been documented in some of the 25 species of crocodiles that live, but how many actually do?

"We performed tests on the 25 species, and 24 of them showed the behavior," said lead author Stephanie Drumheller-Horton, a paleontologist and badociate badistant professor in the Department of Earth and Planetary Sciences at UT.

For the research, Drumheller-Horton partnered with Kent Vliet of the University of Florida and Jim Darlington, curator of reptiles at the San Agustin crocodile farm.

Previously it was believed that species of thin snout, like the Indian gharial, did not roll because their diets consisted of small prey like fish, whole foods.

But it turns out that feeding is not the only time that animals can roll.

"Aggression among individual crocodiles can become quite intense, often involving bites and death throes to establish dominance or competition for women," Vliet said.

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

And the fossil ancestors of modern crocodiles? If they share a body plan and lifestyle similar to their modern counterparts, they may also be able to roll with death.

"The relatives of the crocodiles have played the role of semi-aquatic predators since the Age of the Dinosaurs," Drumheller-Horton said.

Whether in the Northern Territories of Australia, a lake in the Serengeti or a trough in the late Cretaceous, it is likely that a patient predator is waiting in the water to surprise your next meal with a burst of speed, a powerful bite and A rotating finish.

Unravel the evolution of feeding strategies in ancient crocodiles.

More information:
Stephanie K. Drumheller et al, Surveying the behavior of the death roll in Crocodylia, Ethology ecology and evolution (2019). DOI: 10.1080 / 03949370.2019.1592231

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University of Tennessee at Knoxville

Study: Infamous & # 39; death & # 39; almost universal among crocodile species (2019, April 18)
retrieved on April 18, 2019

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