It looks like it's found in Argentina.
When I was a kid we lived in Panama. We had a scout capt in the middle of the wilds called Camp Chagres. My understanding is that the camp closed because two scouts were killed by fer-de-lance bites.....
http://www.survivaliq.com/survival/poisonous-snakes-and-lizards-fer-de-lance.htm
I heard that if you were bitten you would at least lose the limb....if not your life. There's no reason to have a pet like that.
Isn't there some island near there that is uninhabited by humans but overrun with a snake similiar to the fer-de-lance? I forget the name of the snake,but there was a National Geographic special about it. You have to get a government permit to go to it. I remember now,it was near Brazil. I think the snake was a golden lance. The island was just crawling with them.