oh, that's what a "river jack" is. I call those rhinoceros vipers. That one looks fantastic. I like the look of the big chunky vipers, with this one and the Gaboon viper I think being my favourite two species.
"River jack" is a name for many a things, and rhinoceros viper is another valid term for Bitis nasicornis (even though with Bitis rhinoceros, this might be confusing for some); I just thought it was a great name for a great snake, almost worthy its own theme song. ^^
