Cat health problems is a very large subject. Please either scroll down to search manually or please use Google custom search by clicking here . Tardar Sauce (born April 4, ), commonly known as Grumpy Cat, is an American internet celebrity cat. She is known for her permanently "grumpy" facial appearance, which is caused by an underbite and feline dwarfism. Sign Up For Our List. Get up-to-date info on shows, giveaways, news and more.