At the Hippo Pool

By George W. Frame • Photos courtesy of author

Hippos rest in the water for most of the day. The ones above are not bothered by having gulls and cattle egrets walk on their backs. On cloudy days the hippos will sometimes lie on shore, as the one below is doing.

I was surprised one afternoon to see a tiny new hippopotamus at the hippo pool near my house in Tanzania. The water was too deep for the baby, so it stood on its mother’s back. Between breaths, the mother hippo sank under the water just far enough to wet her and her baby, but not so far that her baby went all the way under.

Usually I saw fifteen hippos in this pool, sleeping close together while gulls and cattle egrets walked across their backs. Lately, however, one of the females had been missing. Now I knew why.

The mother had left the group so her baby could be born in a hidden place. After nearly two weeks she brought her baby and rejoined the group. She would have to be careful to keep her baby out of the way of the big adult hippos.

At night the mother hippo went ashore to graze in the grasslands. In the moonlight I watched from my truck as the baby walked next to its mother’s head. That’s a good safe place for a tiny hippo, because the mother can keep close watch. She protects her baby from predators, and watches so it doesn’t get lost.

There were several other mothers and their offspring in the same pool. Females and their youngsters stay together in nursery groups, in places where the water is permanent. This group had a big old grandmother, four of her grown daughters, and all their babies and growing-up offspring.

On mornings when I sat and watched, the “teenage” males were busy in their rough play. They lunged on top of one another’s backs, and with mouths wide open they gently bit and threatened each other.

There was also a big adult male hippo, who claimed this pool as his territory. The big male yawned frequently, showing his huge teeth to intruders. He sometimes sprayed water from his nostrils. After he inhaled a deep wheezing breath, he would call hunh hunh hunh hunh hunh! It sounded so loud in the still evening air.

A male might keep a territory for years before being overthrown by a younger, stronger male. A territory can be as little as fifty yards across, but other territories might be ten times as large. The size depends on the amount of water and shoreline available and on how many hippos live there. The males only defend territories in the water, where they spend most of their time. They do not defend the grassland where they feed.

Hippos can stay underwater for only a few minutes at a time. Then they have to come up for air. They are denser than water, so they naturally sink and walk on the bottom if they want to. But hippos can swim well, too.

For several months I watched the baby hippo in the pool near my home. The dry season came, and the water evaporated until the pool was only a fraction of its former size. The hippos crowded together so they all could stay wet. Each night they had to walk farther and farther into the grasslands to find enough food.

Finally the rains came. Soon the pools returned to their former size. The grasses grew green and abundant. Food was everywhere, and the baby grew big and healthy.

When I finished my research near the hippo pool and moved to another part of Tanzania, I was sad to leave the hippos. But I was happy to know that all of them, even the very youngest, were doing so well.