Eggs.

What's the difference between brown eggs and white eggs?

they come from different animals

No, they don't necessary come from chickens of different colors - it's the breed of chicken, which isn't always just white or brown.

And there is absolutely no difference in the eggs themselves: in taste or nutritional quality. Sometimes you hear that brown eggs are 'healthier' but they aren't. Not because they're brown anyhow.

On the other hand, there is a difference in taste (and often in nutritional value) between battery-chicken eggs that have been on the store shelf for a while, and fresh eggs from free-range chickens.

I know that brown eggs come from Rhode Island Red chickens. I guess white eggs come from other breeds.

I always thought that brown eggs tasted better but I never tried a blind taste test so it could all be in my head. I avoid eggs for health reasons now though I still enjoy them once in a while. No finer breakfast than poached eggs over toast IMHO.