What is the highest altitude you would find poisonous spiders at? Poisonous snakes?

Question

I live at an altitude of 4400' above sea level and heard somewhere that no poisonous insects or reptiles had ever been found above 4000'.

Answer 1

Scrolling down, this article says there are venomous snakes 4,900 feet above sea level in Costa Rica.

Answer 2

wrong - we have black widows and I am at 7000,  pigmy rattle snakes at 5000.