Update:

I have since learned that it sometimes does take more than a week for evolution to occur and that I had been lucky on my other characters. The animal eventually evolved, though by the small percent chance following the "squirms" message.

However, I'm still baffled by the "surprisingly not worthless" message. Some animals on some characters seem completely incapable of resonating strongly for their preferred interaction no matter what I select or how many times I select it. Is this normal? Has anyone else experienced this?