We generally think of dogs as being the meat-eaters, but actually, cats require more protein than dogs, Dr. VanDuzer says, though as they get older their protein requirements change. “As cats age, their kidney and liver can benefit from a lower protein,” says Dr. VanDuzer. She feeds her senior feline Purina Proplan Prime Plus and recommends it as one of the best dry cat foods for seniors. “It comes in both a chicken and salmon flavor and combines prebiotic fiber and multiple vitamins that support muscles, and the immune and digestive systems.” Cats of all ages deserve a loving home and your heart will melt when you see these before and after cat adoption photos.