The snake that is most likely to kill is generally regarded as the Coastal Taipan. I don't think anyone has survived a bite without antivenene. But those who have kept both the Coastal Taipan and Black Mamba say the Mamba is the more dangerous to keep due to being faster and larger, in other words, greater chance of being bitten.
Most of the research I have done would indicate the black mamba bite would be comparable to the Australian mainland Tiger snake, maybe up to a 75% chance the bite will be fatal without anti venene. The Death Adders are at 50%. But the Mamba would be far more dangerous.
I use to keep reptiles, both lizards and snakes but only Tiger snake and Red Bellied Black snake.
