The cats should not eat watermelon seeds. Like apple seeds, the watermelon seeds which contain cyanide make them very dangerous for cats. Cats have a primitive and smaller digestive system. So, the consumption of even two watermelon seeds can make them sick. Moreover, it may cause choking hazards when consumed. Similarly, all the needful nutritional benefits are found in the watermelon flesh and not in the rind. Instead, the rind is difficult to digest for the cats thereby increasing the chances of damaging intestines, choking, or stomach upset. Therefore, before providing the cats, it is advisable to remove the rind.