Why do hippos kill their babies

A South African hippopotamus known as Solly died today after spending three days trapped in a swimming pool. Solly had reportedly been forced out of his herd by more dominant male hippos. How contentious is hippopotamus society?

Pretty contentious, but mostly among males. Hippos congregate in herds (also known as pods) that usually include 10 to 15 individuals, though some herds are much larger. Each herd is presided over by a dominant male; the other members of each herd are mostly females (with which the dominant hippo has mating rights) and young hippos, with a few submissive males. When young male hippos reach a certain level of maturity, they’re typically kicked out of the herd by the dominant male. When two male hippopotamuses fight, they open their mouths wide, sometimes lock jaws with one another, grunt stylistically, and slash one another’s hides with their enormous, sharp canines.

It’s rare for a challenger male hippo to take over a dominant male hippo’s herd. More often, a submissive or young male will join a herd of bachelors and bide his time until he can attract a herd of his own. It’s also extremely rare for adult hippos to kill one another, since their mouths aren’t big enough to fatally gore another hippo’s body. It’s possible, however, for adult male hippos to commit infanticide of other males’ offspring. Infanticide allows male hippos to maximize their reproductive success: Once a mother’s baby is out of the picture, she becomes ready to mate again sooner.

Hippos are territorial in lakes and rivers, where they spend the majority of their time. (They’re not territorial on land, where they graze at night on grass.) They mark their territory by spinning their tails to spew their urine and excrement over as wide an area as possible. Since hippos can die if they spend too much time out of water, they’re more likely to defend their territory aggressively during droughts and in places where water conditions are variable. They’re also more likely to show aggression toward other animals and humans in areas with a history of hippo poaching.

Hippopotamuses are difficult to study in the wild, both because they tend to attack humans who get too close to them and because so much of their lives take place underwater. They communicate vocally underwater and mate underwater. They don’t appear to form close bonds, with the exception of the bonds between mothers and their young offspring. Hippos typically leave the water only to graze, though they don’t have to graze every night to maintain their strength. However, the combination of undernourishment and stress certainly played a large role in Solly’s death.

Got a question about today’s news? Ask the Explainer.

Explainer thanks ecologist Rebecca Lewison of San Diego State University.

These shocking pictures show the horrific moment a baby hippo was viciously mauled to death by the brutal pack.

The gruesome images show the baby hippo, no more than two days old, being introduced to the rest of the pod by his proud mother  but then the pod launch a harrowing attack.

Mother and calf before the incident

The brutal beasts lunged for the helpless calf, tossing him about in the air like a ragdoll as blood spurted and guts went flying.

The bloodbath were caught on camera by James Wilson, on a weekend trip to Hwange National Park, Zimbabwe, while working in the safari industry in Botswana.

James said the traumatic scenes of brutal carnage looked like a calculated plot by the group of adult hippo to attack the defenceless calf.

The pod horrifically attack the calf

He said: “We mostly see hippos lazing in the water with the cute tips of their ears and eyes poking out  they’re seemingly lazy creatures.

“There had been an exception shortage of rain during the wet season, but the heavens opened for two consecutive days.

“We decided to set out for one of the many game viewing hides strategically placed above a waterhole.

The pod horrifically attack the calf

“What transpired was a scene none of us had seen on safari before.

“It became apparent that a mother hippo, separated from the pod, was suckling her new-born calf.

“The mother usually isolates herself from the pod to give birth and slowly introduces the calf when she feels ready  we were fortunate enough to arrive at that very moment, a special experience.

The pod horrifically attack the calf

“Other members of the pod inquisitively made their way to the water’s edge.

“While the mother was protective of the calf, she made no obvious attempt to keep the younger hippo from coming too close as it wobbled precariously during its first few steps on land.

“For no apparent reason the mother began backtracking  something was about to go down.

“What ensured was a scene of complete chaos that none of us expected after such a touching family moment.

The pod horrifically attack the calf

“As if the incessant tapping of the rain drops had caused them to lose all sense of control they attacked the mother.

“Three adults launched themselves towards her and sent her fleeing for safety.

“The calf was left stranded on the other side while they continued to target the mother.

Blood sprays in the air

“Suspecting the calf might be in trouble we watched as a few adult hippo cornered the mother on one side of the waterhole, while about seven hippo began moving in on the calf.

“Chaos commenced once again as they simultaneously lunged for the helpless calf, flinging it into the air.

“This set off the rest of the pod as chaos turned to carnage and the small waterhole turned into a whirlpool of blood and drama.

The pod horrifically attack the calf

“The mother watched helplessly as the entire pod attacked and slaughtered the calf.

“Each adult fought for their opportunity to attack the calf, pulling it from one side of the waterhole to the other.

“Even the most seasoned guides felt a little traumatised by the sight.

A crocodile feasts on the carcass of the calf

“We’re not sure exactly what possessed the hippo to do this  but the point is that this is the reality that is life and death in the African bush.

“Although all a little startled by what we had just seen, we knew we had been fortunate enough to witness an incredible moment in nature.”