Answer:
Yes. They can eat anything humans can.
It all depends on your dog but generally eating a watermellon rind will not harm a dog, it can give some dogs diahhrea,or give some dogs some really smelly gas and/or even frighten the owners when the dogs stool comes out as a light or dark green color.It all depends on how it affects your specific dog..
However dogs can not eat anything that a human can eat.
Avocados (All parts of the avocado and avocado tree are toxic to dogs.)
Macadamia Nuts (Macadamia nuts contain a known substance that is toxic to dogs.)Grapes,Raisins (Grapes,Raisins are dangerous because of a known substance which is toxic to dogs - affects canine's kidneys)
Chocolate (Chocolate contains Theobromine, a compound that is a cardiac stimulant and a diuretic. This can be fatal to dogs.)
Green parts of Tomatoes or Green Potatoes (Contain oxalates, which can affect the digestive, nervous, and urinary systems.)
Nutmeg (Nutmeg can cause tremors, seizures, and central nervous system damage.)
Sugar-Free Foods (Sugar-free foods containing Xylitol have been found to cause liver failure in dogs.)Check with your vet before feeding your dog any kind of human foods.