The Crocoduck is a strawman argument which claims that the absence of any half-crocodile, half-duck creature disproves evolution. The argument was presented by apologists Ray Comfort and Kirk Cameron during a televised debate on the existence of God. During the debate, Kirk Cameron stated the following:
- "Science has never found a genuine transitional form that is one kind of animal crossing over into another kind either living, or in the fossil record. And there's supposed to be billions of them! Now, what I am about to show you does not exist. These were actually created by our graphic artists. But, I want you to keep your eye out for this because this is what evolutionists have been searching for for hundreds of years. Alright? And if you find one of these, you could become rich and famous."
Shorty after he unveiled three imaginary composite pictures depicting a crocoduck (half-crocodile, half-duck), the bullfrog (half-bull, half-frog) and the sheepdog (half-sheep, half-dog).
This fallacy doesn't need much explaining: the theory of evolution does not state that a crocodile has to become a duck, or vice-versa, or that such a thing must have happened for evolution to be correct. Even if a duck were supposed to have evolved directly into a crocodile, nothing says that a duck would have a crocodile head aside from the Photoshopped picture at right.
An intermediate form between a duck and a crocodile is not to be expected because birds and crocodiles are only distantly related. Birds evolved out of an animal similar to Xiaotingia and Archaeopteryx while crocodiles evolved out of different types of reptiles called archaeosaurs more than 50 million years earlier, see Crocodile evolution. Intermediate fossil forms between the birds and their ancestors have been found as have intermediate fossils between the crocodiles and their different ancestors.
"In the first place it should always be borne in mind what sort of intermediate forms must, on my theory, have formerly existed. I have found it difficult, when looking at any two species, to avoid picturing to myself, forms directly intermediate between them. But this is a wholly false view; we should always look for forms intermediate between each species and a common but unknown progenitor; and the progenitor will generally have differed in some respects from all its modified descendants. To give a simple illustration: the fantail and pouter pigeons have both descended from the rock-pigeon; if we possessed all the intermediate varieties which have ever existed, we should have an extremely close series between both and the rock-pigeon; but we should have no varieties directly intermediate between the fantail and pouter; none, for instance, combining a tail somewhat expanded with a crop somewhat enlarged, the characteristic features of these two breeds."
- — Charles Darwin, The Origin of Species
The Crocoduck fallacy demonstrates the complete lack of understanding of Comfort and Cameron regarding biological evolution. They apparently believe that Darwinian evolution requires a direct, single-step ancestor between every two species on the planet. In other words, there must have been not only a crocoduck, but also a croco-beaver and a beaver-duck predating the crocodile, beaver, and duck.