A cold blooded creature still uses it's food to provide energy, so cut that off and they die. It's just they can't use their metabolism to regulate their body temperature. Crocodiles don't become immortal because they sunbathe to keep their body temperature up.
"Great spirits have often encountered violent opposition from weak minds."
Einstein
When I was 5 years old, my mother always told me that happiness was the key to life. When I went to school, they asked me what I wanted to be when I grew up. I wrote down happy. They told me I didn't understand the assignment. I told them they didn't understand life.
- John Lennon