When we (Matthew was complicit!) recently posted a photo showing that you could see the rear of an owl’s eyes through its ears, some confusion ensued, and we didn’t know whether that photo involved removing part of the owl’s ear to expose the inside of its head. So the burning question remained: can you really see the back of an owl’s eye through its ears? We now have the answer.
Thanks to an alert reader, Dr. Kelly Williams of the Department of Biological Sciences at Ohio University in Athens, we’ve learned that the original post was indeed correct. If you peer into an owl’s ear-hole, at least in a saw-whet owl, you can see its eye. Kelly sent an email and photos documenting this amazing fact (reproduced with permission):
Just thought I’d give some info on the photo of the external ear and eye of the owl picture that was posted. The hand holding the owl [JAC: in the original photo] is mine and the owl was indeed alive and flew off just fine. We host several hundred visitors each year to our Northern Saw-whet Owl fall migration station and frequently gently part the feathers (as you saw in the photo) to show people the asymmetrical ear openings. I’ve attached my own photos (so not my hand this time) that show each side. Saw-whets are one of 3 species of owl in NA that have an asymmetrical shape to their external auditory meatus (several species have one ear higher than the other – like the barn owl). In Europe, I believe a greater proportion of owls have this asymmetry. The eye is supported by a sclerotic ossicle.
I believe the picture that was posted was taken by Jim McCormac—more photos and information are at his blog. (If you think the ear and eye are neat – check out the black light photos of the wing that fluoresce pink due to the porphyrins).
Here it is: an unretouched and intact living owl. The eye is clearly visible through the earhole:
And here’s the lovely creature itself, looking a bit peeved (but owls always look peeved):
And here are two pictures from McCormac’s website, Ohio Birds and Biodiversity. The first shows the wings fluorescing pink, the second the total cuteness of these tiny owls (the Linnaean binomial is Aegolius acadicus).
Finally, here’s one of Kelly’s PowerPoint slides showing the asymmetry of the saw-whet skull. It’s quite striking. I’m pretty sure it’s directionally asymmetrical; that is, it’s not random which ear is up and which is down. But that raises the question of how, during ear development, the skull “knows” which side is right and which is left. (By “knowing”, of course, I mean that there must be some biochemical/genetic cues that distinguish right from left.)