What is the difference between a "guess" and a "hunch"?

Can both "guess" and "hunch" be used interchangeably or is there a minute difference? I know it doesn't apply to the phrase 'I guess', but generally when do you use "hunch"?

Guesses are more assertive than hunches. A hunch can be seen as a hint or feeling and is something that typically indicates a suspected outcome or result:

I have a hunch that they are lying.

My hunch suggests otherwise.

I am only working on hunches.

The conveyed message is that there isn't much rhyme or reason behind a hunch. The only backing is... just that it exists. You very rarely have control over hunches and once you can point toward why you have a hunch it starts becoming less of a hunch and more of a guess.

A guess can drift from potshots to educated guesses and are considered more challengeable. Where a hunch simply describes your feelings or thoughts, a guess is expected to have some meat behind it. Asking why of a guess is expected. Asking why of a hunch is pretty pointless.

In terms of use, guess can be seen as a strict upgrade from hunch:

I guess that they are lying.

I guess otherwise.

I am only working on guesses.

The scale does continue from there, but the range of guess is very broad and context is important:

If you had to guess, what is the population of Mexico?

I don't know the answer, but I can guess.

Are you guessing?

This is an educated guess.

I have no idea, but my guess is five.

I can guess.

Beyond guess are words like answer:

This is my answer.

What is the answer?

Is that your final answer?

A "hunch" is typically associated with someone having an intuitive, "gut feeling" about something.

I have a hunch that the plants were moved by an animal.

A "guess" is usually more generic and hints at less intuition or feeling and a tiny bit more cognition.

Can you guess who was at the party?