Hmm, I remember the 'No fruits or veggies' signs all over the place... but animals I'm not sure of. I would imagine he would have to get major permits and such from customs. The best way to know would be to call someone in customs for the section of the border he'd be going over.

Also, you might tell him to be very wary of owning reptiles in Mexico... There are very few places that will care for such creatures, since pet stores are practically nonexistent, and vets that might cater to exotics are really rare and quite expensive. A pet out there is something you picked up off the street or out of the desert (or jungle depending on how far south you are).

I'm typing up what my BF is telling me, BTW, since he's half Mexican and lived there for 18 or so years.