Crocodiles Can Climb Trees, Scientists Say

Crocodiles might be a bit scary, but at least there’s no danger of them lurking in the trees above your head, right? Wrong!

You probably won’t see a tree full of adult crocodiles in the Everglades, but it is possible for juveniles to bask on low-hanging branches or even climb near the treetops, according to University of Tennessee Knoxville researcher Vladimir Dinets and colleagues from Charles Darwin University in Australia, SFM Safari Gabon and Australian wildlife management firm Big Gecko.

Previously, scientists had taken it for granted that crocodiles are “non-arboreal” (to use the more formal term), even though many locals have reported anecdotes of climbing crocodiles. Now, Dinets and colleagues have photographically-documented incidents of crocodiles on three continents sunning themselves on the branches of trees. They published their observations in a paper that recently appeared in the journal Herpetology Notes [PDF].

In North America, the team saw crocodiles up to 1 meter (3.2 feet) long lounging on the aerial roots and low branches of mangrove trees during the day.

“All crocodiles seen in trees were extremely wary, and jumped or fell in the water when the approaching observer was still more than 10m (32 feet) away,” Dinets and colleagues wrote. “This shyness might explain why tree-climbing behavior in crocodilians remains relatively little known despite being relatively common.”

In Australia, members of the team observed freshwater crocodiles attempting to climb chain-link fences up to 1.8 m (6 feet) tall. Young crocodiles were also seen in trees during both day and night.

By far the most commonly observed climbers were the slender-snouted crocodiles of Central Africa. Some African crocodiles roosted as high as 3 meters above the surface of rivers.

"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 said in a statement. "Likewise, their wary nature suggests that climbing leads to improved site surveillance of potential threats and prey."

Despite lacking obvious climbing adaptations, the crocodile manages to find a way up, thus demonstrating its surprising agility.

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

SOURCE: Dinets et al. “Climbing behavior in extant crocodilians.” Herpetology Notes 7:3-7, published online 25 January 2014.