[begueradj]

There is evidence of jealousy behaviors in our closest cousins, the chimpanzees. You can imagine how much that feeling is amplified within humans.

[mathieuh]

I don't think it's as much jealousy in this instance as it is a dislike of unfairness.

My tech lead earns more money than me. This is absolutely acceptable to me because I am aware they are better at programming and they have more responsibilities than me.

If I found out a coworker at the same level as me was earning more than me I would be upset with that situation.