Red Eared Sliders... Happy?

Question
Hi, I'm just wondering if turtles (in my case, baby red-eared sliders) have a way of showing, pleasure/happiness?

I read that turtles liked being petted on their bellies, so being curious, I gave it a shot. My sliders are only about 6 months old give or take a few months, and they are quite accustomed to me lifting them up. One started bobbing its head up and down, and the other opened its mouth each time I petted it (But not in a snappy, agressive way), almost like a yawn. Are these happy actions? Or should I just leave them alone? Thank you in advance?

Answer
Hello Koumiko,
There really isn't a way to show that they are happy, or upset. However when stressed you will most likely be able to tell. I have never heard about them liking their bellies pet however. This is new to me, turtles do not like being handled at all, some will tolerate it but it is extremely rare to find one that will willingly crawl into your hand without some sort of bribe. It is common when they feel threatened or nervous that they will open their mouths not to bite or anything and it may look like a yawn but its basically saying "Dont make another move, I do have teeth" Turning thim upside down to pet their bellies is a big no no as it makes them struggle for air. They really don't enjoy being handled and it can cause un intentional stress. The only reason I handle mine is for cleaning purposes. Other then that they are free to do what they feel in their tank... Besides trying to climb INTO the water filter, that can get annoying. Ha ha

Best of Luck,
Yexalen