According to this Wiki article, “The most commonly observed two-headed animals are turtles and snakes.” What is it about these reptiles that increases the probability of dicephalism, compared to other animals?
bump
Someone’s gotta know about this.
I’m not sure the claim is true. The wikipedia article cites a Pravda article that doesn’t provide any references. Pravda mentions a researcher, Andrew Khund, who doesn’t show up through Google or PubMed. Nor can I find any other evidence to back it up.
WAG about snakes: Because they are resilient animals with incredibly efficient metabolisms? It’s easier to survive having two heads when you only have to manage eating once every few weeks or months. But then I’m interpreting “commonly observed” to mean"surviving long enough to be observed," not necessarily “proportionally more being born”.
I’m not sure this is actually true. A web search shows lots of photos of two-headed snakes and turtles of various species, but quite a few lizards as well.
There are only a few of salamanders, and I didn’t see any photos that looked to be of authentic two-headed crocodilians or frogs.
Before speculating on causes in any differences, however, I’d want to see more evidence that the differences actually exist. As rhysf says, there doesn’t seem to be any actual research on this cited.