What do green, yellow, and red rings mean in Pokemon Go?

[iMore Question]

What do the different colored rings mean? Do they do different things?

 

[John Yester]

• Green Circle – The Pokemon is the easiest to catch, could be caught on the first try.
• Yellow Circle – The Pokemon is the harder to catch, this Pokemon may take a couple of tries to catch.
• Red Circle – The Pokemon is the hardest to catch, if you don’t throw a perfect strike, odds are this Pokemon will run away.

 

[robertk328]

• Green Circle ? The Pokemon is the easiest to catch, could be caught on the first try.
• Yellow Circle ? The Pokemon is the harder to catch, this Pokemon may take a couple of tries to catch.
• Red Circle ? The Pokemon is the hardest to catch, if you don?t throw a perfect strike, odds are this Pokemon will run away.

Encountered a Tauros yesterday that was red. Had one chance and he ran Leveled up to 12 and got some super balls -- if I see one again that's what I'm throwing!