That's because you've not bothered to do this special thing that scientists sometimes call "research" and ordinary folk call "looking up stuff". Do you seriously think that this is an original argument? It's been around since forever. And it's the same argument over and over again:
# Randomly select a species.
# Describe some aspect of it which is complex.
# Exaggerate some other aspect of it.
# Conclude that it could not have evolved.
(to borrow from Mr. Wong). Whenever creationists say "evolution couldn't have created X", they really mean "I personally cannot imagine an evolutionary process that could do so." No more, no less. It's an argument from ignorance--worse, most of the time it's an argument from their
personal ignorance.
How about this: if you have a particular animal in mind, just
look around to see whether or not it has been answered. That way, you might question the validity of the answers or your understanding of it or whatnot, instead of looking like a lazy douche that wears ignorance as a badge of honor.
(Well, at least it's not that old "bananas: the atheists' worst nightmare" nonsense again.)