Nature and Human Choices

Consider this peculiar example that I saw on the Discovery Channel - King Cobras have an unconventional weapon of poison which if used can kill victims almost instantly. However when King Cobras fight with their peers in the mating season, they never use this weapon. This is despite the fact that they are themselves vulnerable to each other's venom and can die instantly if any other cobra bites them. One can compare this phenomenon with the nuclear deterrence followed by countries in the world today and can possibly hypothesize that collective human conciousness is aligned with the laws of nature. The mismatches in human societies however can pose an ethical question. What preferences/inclinations are acceptable and what dispositions are allowable. When decisions are made giving emphasis on preferences or choices, the question gets distorted from "What is natural or ethical?" to "Who takes decisions?". Or in other words - "How to explain a tribe of 250 people with a nuclear bomb in their possession that its use, against the tribal belief, would be devastating."