What's with my Chao's behaviour?

[FluffyCats]

In Sonic Adventure 2 Battle, I have my dark Chaos Chao, Vanilla. When I pick her up, she gets all happy and starts to snuggle in Tails' hands. I hold her for a short period of time (about 15 seconds) with Tails, she then starts to get mad and starts to struggle to get out. I've never abused her with Tails, and if I ever abused her, it was with another character and on accident. This has also happened with my hero chao, Hammy. Why is this happening?

[FedoraBrella Chao]

It's hungry.

[Chao Professor]

Hey don't worry, this is normal, and happens with almost all my chao. I guess they just don't like to be held for too long, and even though I never abuse them, they still do it. I'm not completely sure of the conditions in which a chao will do this, however, because I seem to own several chao who never really do it.... I suppose it could be hunger, or to do with their personalities. Strange, but you gotta admit it's adorable to watch and listen to
`
"mm-nyahh!"
"nya,nya,nya!"

So cute!!!!