Friday, November 30, 2012

CrocLog Podcast Episode 13

As promised, here's Episode 13 of the CrocLog Podcast. This is a special edition that focuses on the Christmas Croc Fest 2012, and we speak with one of the organisers Shawn Heflick who is hosting the event at his place in Florida. Some of you might know Shawn as one of the hosts of The Python Hunters which airs on Nat Geo Wild in the US and National Geographic Channel in the UK, and he's a bit of a croc fanatic.

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.

Wednesday, November 28, 2012

CrocLog Podcast Episode 12

It's nearly Christmas, and that can only mean not one, not two, but three CrocLog Podcast episodes over the next few weeks! Here's the first one, Episode 12, which is a nice long one to make up for the interval since the last one. Episode 13 will be coming shortly afterwards and is much shorter, where we'll be talking about an upcoming fund-raising event for crocodiles.

In this episode we interview Subir Chowfin about his work on gharials in the Corbett Tiger Reserve in India. Brandon and I also bring you up to date on the latest crocodile news, some interesting recent research on crocodile sense organs, Brandon updates us on crocodile attacks, and I try my best to keep the distracting noise in my microphone to a minimum. The wonders of modern audio technology.

Links to the podcast and a few of the stories below:

Friday, November 09, 2012

Crocodile skin is more sensitive than your fingertips

Crocodiles are covered in a scaly skin. And on each scale are tiny pressure receptors called ISOs, or "integumentary sense organs". These are very densely packed onto the scales around the jaws, but can also be found across the whole body. Well, except alligators and caimans. For reasons that aren't entirely clear, alligators and caimans have no ISOs on their body scales, only on the head.

It's been known for decades that ISOs are sensitive to pressure. They function as mechanoreceptors, which means that when they are deformed by pressure, they send a signal to the brain. Touch something with your fingertip - the texture you're feeling is the result of tiny deformations causing nerve signals to be sent to the brain which interprets them appropriately. As a result of this study, we know that the pressure-sensitive ISO organs on the head and jaws of crocodiles are so good at detecting pressure changes, they are even more sensitive than human fingertips. That's pretty darn impressive. Earlier work suggested that ISOs served to detect pressure changes at the water's surface, but this latest study proves they're a lot more versatile than that. They can detect a wide variety of touch sensations, pressure changes, and vibrations. Everything from delicately manipulating hatchlings to detecting minute pressure changes created by fish swimming past their jaws in the water. And more. We're working on one particular study at the moment that has just had a lot of light shed on it by this news.

Impressively, the study also clearly shows that the ISOs on the body also function as mechanoreceptors. The feet in particular are very sensitive, and could detect pressure changes in the water (and certainly touch). I once described the crocodile as being surrounded by a pressure sensitive net, so it's very cool to see the science behind it detailed so thoroughly and effectively.

I strongly recommend that you read the full paper at the Journal of Experimental Biology. There are some very cool diagrams of nerve networks, and it will really give you an appreciation for just how remarkable the ISO system is for crocodiles.

Thursday, November 08, 2012

How to save Orinoco crocodiles

Orinoco crocodile, Photo by Roger Manrique

The Orinoco crocodile, Crocodylus intermedius, is a Critically Endangered species found only in restricted areas of Colombia and Venezuela. It's one of a handful of croc species that are in serious trouble right now, but there are ways in which you can make a difference. The easiest of these is to raise funds to support an active and effective conservation and management program, and right now you're in luck because the Christmas Croc Fest 2012 is raising money for such an program. We'll be highlighting more ways in which you can make a difference to crocodilian conservation efforts around the world in the coming months, so right now it's the turn of C. intermedius to bask in the spotlight of concern. I'll hand you over to the organising committee for the Croc Fest after the break, and they'll tell you exactly why you need to attend.