Why Does a Male Hippopotamus Kill His Own Offspring?

A male hippopotamus may kill his own offspring primarily to eliminate future competition for dominance and to increase his reproductive success. While this behaviour—known as infanticide—often targets the offspring of other males, it can also extend to a father’s own biological calves under specific social and environmental pressures.

After a 243-day pregnancy, the mother hippo gives birth to her calf, a fact that might shock you. However, a brutal scenario unfolds if the newborn is male. Consequently, 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 the group successfully 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 ensues between father and son, which ends when one dies or the younger male leaves the group.

📚 This Behaviour Is Not Exclusive to Hippos.

In nature, several other animal species exhibit similar behaviour. However, hippopotamuses demonstrate this tendency toward infanticide particularly clearly.

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