[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: climing crocs continue

        I passed some more of your comments on to Adam this morning, and
here's his reply:

>From: "Adam Britton" <abritton@crocodilian.com>
>To: "chris brochu" <cbrochu@fmppr.fmnh.org>
>Subject: Re: climing crocs continue
>Date: Thu, 7 Jan 1999 02:06:46 +0930
>X-Msmail-Priority: Normal
>X-Priority: 3
>Mime-Version: 1.0
>It's hard to judge these stories of climbing crocs without more
>information. Climbing a tree could mean a very low tree, one surrounded by
>creepers and vines to assist climbing, or one with several intertwined
>branches or a trunk sloping at an angle of 45 degrees.
>If we're talking a near vertical tree trunk here with virtually no branches
>or covering vegetation, then I find it very hard to believe that an *adult*
>Nile crocodile could climb such a tree. By adult, I'm thinking of a 10
>foot+ animal. The weight of a 10'+ animal is 150 - 200kg approximately,
>which is an incredible mass to haul up a tree trunk when you consider that
>the croc has 3 very stubby claws on each foot, at the end of 3 very stubby
>toes (of those which have claws on, that is), at the end of stubby legs
>which in unison have difficulty raising the entire body off the ground and
>walking for more than a few metres in most cases before stopping (although
>Niles can walk overland for distances of 50 to 100 metres before stopping
>in some cases) - which is considerably easier than hauling the same body
>vertically up a trunk which either requires sharp claws to prevent
>slippage, or requires a hugging grip (which crocs can probably do, but
>while climbing?).The crocs back legs are considerably stronger than the
>front legs, yet it's the front legs which are more important in climbing
>and maintaining a grip I would have thought. A crocodile just doesn't have
>the right "gear" to make climbing trees easy. In fact, I could analogise it
>to hearing a story about an arboreal horse - hooves for climbing?
>Of course, that brings us to the next point. In theory, a horse might be
>able to climb a tree *if* that tree was in some way easy for it to climb.
>Now, I can picture trees which would be easy to climb with many branches or
>vines to hook legs around, for example, with the back feet pushing the body
>up from behind, and the front legs simply acting like grappling hooks but
>not actually contributing to pulling the animal up... if you see what I
>mean. The body is pushed up the tree by hind limbs, in other words, not
>pulled by forelimbs as you'd normally expect, and descent was prevented by
>thick foliage or branches.
>All this comes down, however, to the fact that crocs are simply not suited
>to climbing trees. That's why jaguars hide their carcasses up there in the
>first place. And a hatchling would definitely not be in a good position up
>a tree - they're not active hunters, but sit and wait predators, and being
>in a tree is somewhat advertising your presence to the local predatory
>birds I'd have thought. Such instances would be extremely rare.
>I wonder if the quoted TV show illustrated the *entire* sequence of the
>animal climbing up the tree (if so, please send me a copy!) or whether it
>was cut to imply the same (knowing how these documentaries are made, I take
>everything I see with a grain of salt!). It would be an amazing feat if it
>were true, and certainly the exception rather than even 2 standard
>deviations from the rule!
>All this talk has triggered a memory! I do remember now that Silver Springs
>told me one of their C. c. fuscus had actually managed to climb up and sit
>atop their glass partition, peering happily at the tourists a few feet away
>from it. They didn't know how it could possibly have gotten up there, but
>there were various logs / branches nearby which it could have climbed.
>These were not vertical, but at a fairly steep angle. We speculated that
>the caiman could have leapt onto one branch (maybe that's how the Nile got
>started, then clambered onto a low branch?) and made its way across another
>at a fairly low angle. The caiman was perhaps 1.5 metres long.
>I still would like to see this footage. In the meantime, I'll ask Grahame
>Webb in the morning if he's heard of anything like this and whether we
>should redesign the croc enclosures. ;)
>Let me know if there's any more info - this is fascinating.
>ps. The feral baby crocodiles up trees in England just pushes my
>willingness to believe it too far. No baby croc would survive in such a
>climate for very long, certainly not up trees, and where did they all come
>from, and why do these unbelievable feats always get reported from 150 yrs
>ago when no one can verify it and which can't be seen today by modern
>zoologists who spend years studying and watching the animals? Maybe they
>forgot to look in the trees?!!! They'd be too cold and too inactive to
>escape from the numerous mammalian predators for much of the year. I had to
>check that it wasn't April 1 when I read that!
>Dr. Adam Britton  |  abritton@crocodilian.com
>Crocodile Research  |  http://crocodilian.com

Christopher Brochu
Department of Geology
Field Museum of Natural History
Roosevelt Road at Lake Shore Drive
Chicago, IL 60605

312-922-9410 x469