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Treetop Alligators

Posted by Richard Conniff on February 11, 2014

This is a deeply disturbing idea.  Imagine paddling down a stream and looking up to see an alligator or crocodile looking down.  Check out the press release:

treetop alligatorWhen most people envision crocodiles and alligators, they think of them waddling on the ground or wading in water — not climbing trees. However, a University of Tennessee, Knoxville, study has found that the reptiles can climb trees as far as the crowns.

Vladimir Dinets, a research assistant professor in the Department of Psychology, is the first to thoroughly study the tree-climbing and -basking behavior. The research is published in the journal Herpetology.

Dinets and his colleagues observed crocodilian species on three continents — Australia, Africa and North America — and examined previous studies and anecdotal observations. They found that four species climbed trees — usually above water — but how far they ventured upward and outward varied by their sizes. The smaller crocodilians were able to climb higher and further than the larger ones. Some species were observed climbing as far as four meters high in a tree and five meters down a branch.

“Climbing a steep hill or steep branch is mechanically similar, assuming the branch is wide enough to walk on,” the authors wrote. “Still, the ability to climb vertically is a measure of crocodiles’ spectacular agility on land.”

The crocodilians seen climbing trees, whether at night or during the day, were skittish of being approached, jumping or falling into the water when an approaching observer was as far as 10 meters away. This response led the researchers to believe that the tree climbing and basking are driven by two conditions: thermoregulation and surveillance of habitat.

“The most frequent observations of tree-basking were in areas where there were few places to bask on the ground, implying that the individuals needed alternatives for regulating their body temperature,” the authors wrote. “Likewise, their wary nature suggests that climbing leads to improved site surveillance of potential threats and prey.”

The data suggests that at least some crocodilian species are able to climb trees despite lacking any obvious morphological adaptations to do so.

“These results should be taken into account by paleontologists who look at changes in fossils to shed light on behavior,” said Dinets. “This is especially true for those studying extinct crocodiles or other Archosaurian taxa.”

Dinets collaborated with Adam Britton from Charles Darwin University in Australia and Matthew Shirley from the University of Florida.

Research by Dinets published in 2013 found another surprising crocodilian characteristic — the use of lures such as sticks to hunt prey. More of his research can be found in his book “Dragon Songs.”

Source: Dinets V, Britton A, Shirley MH. Climbing behavior in extant crocodilians. Herpetology Notes, 2014

7 Responses to “Treetop Alligators”

  1. I love it! Herpetology and herpetoculture got me into wildlife issues…

  2. I have another paper about croc behavior currently under review that is way, way more scary…

  3. Nancy said

    Reblogged this on "OUR WORLD".

  4. Can crocodiles really climb trees? http://crocodilian.blogspot.com.au/2014/02/can-crocodiles-really-climb-trees.html

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  6. JDK said

    I have to ask if anyone here bothered to read the actual paper? It has no serious data, no experimental evidence suggesting this is for thermoregulation or surveillance, and was published as a note in an obscure journal when other respectable journals likely wouldn’t accept this. Most of the anecdotal evidence revolves around individuals in trees or mangroves that require no special abilities. They have no evidence that these individuals make it to the canopy regularly and then conveniently suggest that the individuals “fall” from all of 1 meter above the water because they are skittish. This is PR-inflated nonsense. Based on some of the photographic “evidence” presented in the article then we might as well say turtles climb trees as well. I’m sure the authors are working on a similar paper that can be circulated without any critical reception.

    • vdinets said

      I wouldn’t call Herp Notes “an obscure journal”, and I don’t know what you mean by “serious data”. The paper doesn’t make any claims not supported by evidence, it just discusses various possibilities.
      Since the paper came out, some new evidence has come to light, including, for example, this photo:

      and making people aware of the subject was precisely what the paper was intended to do.
      As for media coverage, me and my co-authors are not responsible for it🙂 In all interviews I’ve been asked for, I always point out that the paper has no new revolutionary data, that the crocs’ climbing abilities have been known to people working with crocodiles for decades, and that the purpose of writing the paper was simply to make those outside the field aware of these abilities, since they have never been properly documented.
      And, by the way, at least one species of turtle can climb trees. https://en.wikipedia.org/wiki/Big-headed_turtle

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