She must be cheerful. She’s smiling, isn’t she? Well, no, that may be a flehmen response, where she’s smelling / tasting the air.
This image shot with the Sony 135mm f/1.8 GM on a Sony A1, at ISO 100 f/5.6 1/400. Only processing after setting white balance was cropping to 3000×2500, down from the 8640×5760 of the full frame.