Jan 21, 2009

Bifocal Fish

Jelo has introduced yet another new critter to Ugly Overload. Everyone say hello to anableps (Anableps anableps), the bifocal fish.

This fish would do Benjamin Franklin proud. Some of you bespectacled readers might wear bifocal lenses so that you can with a flicker of your eye see something up close and then far away (something we non-spectacle-wearers take for granted). These fish have taken that idea and modified it for their own uses. Their pupils are divided horizontally, allowing them to at once see both above the surface of the water, and below it. Since they spend most of their lives swimming in schools skimming the water's surface, this is a handy trait to have.

My, what divided eyes you have.
All the better to see both prey and predator, my dear.

But more than just those eyes, check out that grimace. Why so sad, bifocal fish?

Thanks, Jelo.



6 comments:

That Rascal said...

Cool! I think I found me a favorite ugly fish.

Anonymous said...

love the mouth

Anonymous said...

If I saw him looking at me from the surface of a pond, I'd have that he was a frog.

Though not ugly, eagles and other birds of pray have bifocal vision, except their vision is telescopic in the middle of the eye. This allows them to see their surroundings from their peripheral vision while zooming in on prey on the ground.

Raging Wombat said...

That's new to me about the birds of prey. Very cool.

Anonymous said...

Let me clarify my previous statement by saying that the eagle's eye doesn't have a binocular "lens" in the middle of its normal lens. The eagle's eye has two foveas, one that produces normal vision and another in the middle of that one which produces a highly magnified image.

Don't want to create any confusion since the fish on display here has bifocal lenses.

Anonymous said...

Oh, and the aforementioned mudskippers have segmented retinas which have rod receptors above and cone receptors below. This gives them color vision above and monochrome vision below!