Ging, smaller-breed dogs are more likely to develop than either larger-breed dogs or aging cats

The chronic valvular disease may affect many breeds but is the most common in smaller breeds. Many aged dogs develop some valvular degeneration, but it is mostly on smaller breeds that heart symptoms come up. This is a degeneration most likely connected to genetic factors. 

cats appear to have glowing cat eyes because the back of their eyeballs includes a special reflective surface called the tapetum lucidum. this lets them see better during the night, giving them a much better vision.