I saw a variation of the baby gag where the person is asked to think of a four legged land mammal. Whose is this?

Perhaps a DNA test is in order. Maury?

Nick,
I don't know the answer to who's it is and I've never seen it being credited to anyone or sold as a stand alone gag/efect by anyone but I've certainly seen it performed by quite a few. Those that immeadiately spring to mind are: Derren Brown, who used it as part of the opening effect in his 'Something Wicked This Way Comes' tour and Nick Lakin who has included it as part of his marketed effect 'Cereal Killer' but I'm pretty sure that it's not original to either as it's a pretty old (25+ years) bit.

Neal.

So it's very different from the Pig effect.

Nick,
Given that you've now throw in a 'pig' reference it occurs to me that you might be describing something slightly different from what I originally thought from your initial post.

There is a mentalism effect/gag item by Danny Archer called 'In a Pigs Eye'. The sales copy describes it, inaccurately to my mind, as being, "...an update of the old baby gag...". Maybe this is what you are referring to/thinking of? It's a completely different gag/effect/routine from the one I mentioned in my previous post.

You can check it out here

Neal

Thanks Neal! That is exactly what I was referring too!

I've also seen it down with stick figure, bar codes, maps, phone books.

Cody Fisher has a routine like this too the 52 thoughts
animal,bar codes,cards and the final revelation.

Miracle Factory puts out a version also.

Cody fisher predicts a land mammal in his comedy confabulation routine

Steve Kissell had a routine along these lines many years ago.

I saw the gag on an Aldo Columbini DVD