Polar Bears have White Fur?

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Wow. On page 304 of Futuyma's college textbook "Evolution" 3rd edition he mentions that polar bears have white fur and that it makes sense given their surroundings. The only problem is the fur of a polar bear is actually hollow translucent tubes that only appear white due to the way light is scattered within those tubes. Polar bears appear whiter when the Sun is higher.

There are bears with actual white fur. They just aren't polar bears. Futuyma doesn't have any idea how the polar bears evolved hollow tubes for fur.

Now by evoTARDs "logic" we can summarily dismiss everything Futuyma says in that book due to that whopper of a mistake. But that is unfair. We can dismiss what he says because he doesn't provide any evidence for anything. He just says that natural selection is the only known mechanism to produce adaptations. He never says how we know that- no evidence at all. He just points to adaptations and says it is evidence for natural selection based on his original bullshit lie.

The book is purely for indoctrination.