Besides getting eaten hippos have to worry about other things. One thing they have to worry about are droughts. A drought is when it doesn't rain for an extended period of time. They also have to face disease. It is much harder for them because they do not have cures. The biggest challenge a hippo faces is disagreement. If you're a calf and you disagree with someone you may be bitterly crushed. Even your own parent might kill you.