Next up in December is our Christmas Special where we'll be answering a lot of questions from our listeners. It should be a fun time, so watch this space.
Click below for the podcast, plus links to where you can learn more about the Christmas Croc Fest 2012.
Christmas Croc Fest 2012 Facebook page:
https://www.facebook.com/events/321891504576700/
CrocBlog post with more details on what, when and where:
http://crocodilian.blogspot.com.au/2012/11/how-to-save-orinoco-crocodiles.html
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3 comments:
I have an explanation of why we can observe crocodiles safely at the riverbed,
They are forced to keep their mouths shut beyond a certain depth, because the water pressure at that depth is large enough to push back their paletal valve and can flood their lungs with water
So at a certain critical depth, it is safe to approach both saltwater and Nile crocodiles if you can avoid getting head butted by them.
That's not how the palatal valve works though. First it's surprisingly strong because it's reinforced with cartilage (specifically an extension of the hyoid cartilage surrounding the glottis). Secondly, it opens by being pulled forwards and downwards, so actually water pressure forces a tighter seal rather than the other way around. Crocodiles are also quite capable of opening their mouth underwater, and in fact one thing we did in the Okavango was offer a white object to a crocodile underwater (around 7-8 m deep) and she reached over and grabbed it in her mouth before swimming to the surface (and shortly afterwards discarding it). So yes, these crocs are fully capable of biting divers, which is why it has to be done with extreme caution and under the right conditions.
Thank you for taking the time to post an answer.
I stand corrected.
I was wanting to do an experiment on water pressure on a croc's jaws.
We know that the pressure of water at a depth of h is h*d*g. where h is the height of the water column at that depth, d is the density of water and g is the acceleration due to gravity.
At a depth of say h meters, the pressure would be p_atmosphere + p_water-column.
Given the area of a croc's upper jaw we can calculate the force it experiences at that depth. We want to see if the ability of a crocodile to open its jaws wide diminishes with depth or if the force of slamming them shut at calibrated depths diminishes as the depth increases.
The crocodile probably drops its lower jaw and raises its upper jaw simultaneously when opening its mouth
I doubt that a crocodile at a depth of 10 meters can open its jaws wide with the same ease and slam them shut with the same incredible force as it does at the water surface.
Divers who are not harmed when swimming with wild crocodiles may choose to dive with them in winter when the water temperature is colder and causes more sluggish behavior on part of the crocodiles.
Beyond, that i was curious about effective crocodile repellants using which we can establish a perimeter of safety around a diver or swimmer.
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