Asked by: Lisa Milne (age 14), Oxford
Cats have the muscular ability to make facial expressions that resemble smiling, but it’s nothing to do with happiness! Certain odours, especially pheromone-rich ones like urine, can trigger the ‘flehmen response’, where cats draw scent particles to the roof of their mouth to be analysed by their extra sensory receptor, the Jacobson’s organ. This behaviour is characterised by curled lips, a tilted head and squinting eyes – all of which can look like smiling. Cats may also bare their teeth in a kind of grin when feeling aggressive. Positive signs of a contented cat include purring, slow-blinking, paw-kneading, head-rubbing, meowing and tail-flicking – but never smiling!