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Thursday, April 22, 2010

Orca Eyeballs and Eagle Eggs

I work with a great group of naturalists and we are always coming up with new questions, doing research, and sharing answers as we continue to learn more about the local wildlife and ecosystem we love so much. Sometimes these questions that we don't know the answers to come from inquisitive passengers who stump us, and other times the questions come up over happy hour at the local pub. I did a post like this before, talking about male versus female sea stars and killer whale body temperatures - and apparently some other people come up with the same questions because over time this post continues to get a lot of hits! So here are a couple more of our interesting questions and their answers.....

How big is a killer whale eyeball?
This question was asked by a child, and other than, "It must be larger than a human's", none of us really knew the answer. The internet, which often turns up answers to our questions, came up dry on this one, although I did learn that a blue whale eyeball is about 5-6 inches in diameter, and a human eyeball is about an inch in diameter. I e-mailed a local expert who does necropsies, and he didn't know either, so the question continued to spread. Finally, a scientist from NOAA who had participated in a killer whale necropsy sent us a photo, showing us definitively that the answer is a killer whale eyeball is just over two inches in diameter.

How big are bald eagle eggs?
The bald eagle is a large bird (with a body length of about 3 feet, a 6-7 foot wingspan, and a weight of 8-15 pounds), but how big is a bald eagle egg? I've compared a couple of different sources, and it sounds like an eagle egg is about 3 inches long and weighs about a quarter of a pound. So how does this compare to something like a Canada goose (body length up to 3.5 feet, 4-6 foot wingspan, weight of 6-14 pounds)? Goose eggs are just slightly larger.


Lancashire and Lakeland Outback Adventure Wildlife Safaris said...

There seems to me to be a biological limit on the size of eyes if whale eyes are so relatively small compared to other eyes...or is it that they just don't need bigger eyes...discuss


Dave (150)

Monika said...

It does seem that may make sense in that the oceans are dark so visual cues aren't as important, but then again there is evidence some species hunt visually or at least using visual clues so I wonder if there is some biological limit as well. I'll bring this topic to the table with my naturalist friends over our next drink!