This is with regard to the the post where I was talking about the design of the visual system for predators and prey. I had taken an example of a chameleon for my explanation but could not photograph it on time :(. A frog never the less is an equally good specimen for this dual role played by many creatures in nature. Moreover, I had got a really good side shot of a frog when I had been to Agumbe and wanted a reason to share it. At that time I didn't know I would be coming up with this blog, or would have photographed the FV also. I thank Kalyan Varma for allowing me to use the FV of the frog captured by him here.
Observe the design of its face and eyes. The eyes are placed at almost 45 deg to the face. In the side view it can keep an eye on almost one complete side of its body and watch out for predators.
In the front view you can see that they still have some room for common visual region in order to perceive depth which will be used to strike the prey with their tongue.
2 comments:
Do all amphibians have this 45 deg vision ? Is it some special evolution thingy in these?
The main concept here is not whether it is an amphibian or not, it is about the creature playing the dual role of a predator and a prey. Evolution has given them such a vision because they have to survive from a lot of predators like the snake and other bigger reptiles and along with that make their livelihood by hunting smaller creatures (like say flies which can escape off quickly if missed @ one shot). So they need a mixture of both depth perception (for hunting) and a wider angle of vision (to look out for danger). With depth perception they will be able to strike on their target precisely. In our case (humans) most of the visual region is overlapped to perceive depth.
I will be explaining in detail about how overlap in the visual regions will crete depth later on.
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