It turns out that I was wrong and Kirk Cameron was right. Evolution should be able to produce a crocoduck.
And it did.
Hemant Mehta pointed out on his blog that a paleontologist Paul Sereno described the recently-rediscovered Spinosaurus aegyptiacus as “a chimera — half duck, half crocodile.” See Science magazine for more details.
And so I will admit it. I was wrong about the crocoduck – just as Kirk Cameron was wrong about evolution.