Just like humans, the animals at the National Zoo get routine health exams. This is true for gorillas, lions, iguanas, flamingos, and a whole lot of other Zoo animals. Sometimes animals show no sign of injury or illness, but when they get a physical the veterinarians find a problem.
Asian small-clawed otters in zoos sometimes get kidney stones, so the vets make sure to check each otter carefully for stones during an exam.
What tools would you need to diagnose kidney stones?