system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How can Animal Keepers get really close to animals like Tigers or Lions and not be killed?

I've always thought that large cats like Tigers and Lions were almost always hostile, yet you sometimes see gifs of animal keepers basically hugging those types of large cats. How is this possible?
gpt
Most animals don't know whether or not they can kill a human, so they won't try unless in a desperate situation. Also, trainers usually imprint on animals at a young age so that they feel comfortable around the trainer, basically like adopting them.