What is the difference between a white water kayak and other kayaks?

white water kayaks tend to be a bit shorter than other boats (excluding play boats (very short)) they may have more padding and seat straps to keep you more secure, and better foot rests as you put a lot of force on them when paddling white water. "white water spec" normally means better foot rests and seats. "creek" boats, for bigger white water (also called Large Volume (lots of water!)) will sometimes be more bolbus behind the paddler, this means the boat will have more volume and will want to float more when it gets pushed under water, this also give more room for storage (first aid, rescue kit etc)