A good article from Creation Ministries about why snakes adapting to cane toads is natural selection not evolution

Do toads goad snake evolution?

by David Catchpoole

First published: 27 April 2006 (GMT+10)
Re-featured on homepage: 10 March 2021 (GMT+10)

When leading public institutions repeatedly broadcast as fact that ‘we see evolution happening today’,¹ it’s not surprising that many people believe it.

One example is a recent prime-time breakfast radio segment on Australia’s national broadcaster, ABC Radio National. The University of Sydney’s Professor Richard Shine told the presenter Fran Kelly that he and his co-researchers studying snakes have observed ‘genuine evolutionary changes’.²

What were they? Allegedly snakes are evolving to cope with the spread of cane toads across the Australian continent. (Cane toads were introduced to north Queensland in the 1930s, and have steadily expanded their range, moving south into New South Wales and west into the Northern Territory.) The changes are making snakes ‘much less vulnerable’ to the toxin in the toad’s skin. (One reason that the cane toad has spread so rapidly is its toxic gland that can kill native predators that eat it.)Creationists do not dispute natural selection—indeed it is an important part of the biblical creation/Fall/
Flood/Dispersion model, and was theorized by creationists even before Darwin!

But as the interview progressed, the discerning listener would have picked up from Professor Shine’s own words that he and his colleagues had not observed evolution at all. Rather, it was an example of natural selection acting to favour certain already-existing genetically determined traits in the snake populations. Creationists do not dispute natural selection—indeed it is an important part of the biblical creation/Fall/Flood/Dispersion model, and was theorized by creationists even before Darwin!

The researchers had firstly been able to rule out learned behaviour as a factor in this case. ‘We’ve done a bunch of trials to see if it could just be that the snakes are learning and so forth but they seem to be remarkably stupid …’, said Professor Shine, going on to emphasize the genetic basis to snake behaviour:

‘Basically you’ve got a strong genetic component to feeding responses, and some snakes really go mad on eating frogs and others really want to eat nothing but mammals and so forth, and it’s actually pretty sophisticated. And there’s a lot of work overseas showing that even within a single litter of baby snakes you’ve got genetic variation in what kinds of things they treat as prey. And it’s just that the only snakes that survive after the toads arrive are the ones that happen to be born with a set of genes saying: “If it looks and smells like a cane toad, don’t eat it.”’

And genetically-determined physical attributes such as the snake’s head dimensions and body size are key factors too.

‘Essentially the size of the toad you can eat depends on the size of your head, so if you’ve got a small head you can’t eat a very big toad.’

So, if you’re a snake, having a small head stops you eating big toads, which have more poison, therefore helps you to survive. And having a big body helps as well:

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