Why Does a Male Hippopotamus Kill His Own Offspring?*

You’ll Be Shocked to Know.
Think about it: after about 243 days of pregnancy, a mother hippo gives birth to her calf. But if the newborn is male, a brutal scenario begins to unfold. The father becomes the greatest threat to his own baby’s life!
🔒 The Mother’s Anxiety and the Family’s Vigilance
After the baby is born, a strange tension spreads through the entire group. To protect him from the father’s attacks, the family keeps constant watch. The father is always looking for an opportunity to kill his own child.
🦛 The Social System of Hippos
Among land animals, the hippopotamus is the third largest species. A typical group consists of 6–10 individuals, with only one adult male and the rest females. The male is the absolute ruler of the entire group—his main goal is to maintain his “kingdom.”
For this reason, he cannot tolerate the presence of any other male within the group or his harem.
👦 If the baby is male…
The dominant male perceives the newborn male calf as a future political threat. One day, this little hippo could grow up and take over leadership. Therefore, the father tries to kill the calf as soon as the opportunity arises, especially if the baby does not submit or show obedience.
😔 If He Survives…
If the mother and group manage to save the calf, they must raise him secretly and with great difficulty. Eventually, the young male grows up and rebels against his father.
A violent battle then begins between father and son—ending either with the death of one of them or with the younger male being forced to leave the group.
📚 This Behavior Is Not Exclusive to Hippos…
Similar behavior is observed in several other animal species in nature. However, this tendency toward infanticide is particularly pronounced in hippopotamuses.

Source: National Geographic — Why Male Hippos Kill Their Young, 2017.