River horses

We sat in our land rover in front of the Mara river where a bunch of wildebeest were gathering. They take a long time to make up their minds about whether to cross or not, and after a few hours’ wait you could just see the crowd thin out and disappear. I found looking at them quite boring. The river took a bend just to the left of where we’d parked. There was a bloat of hippos right in front of us, and another bloat almost out of sight around the bend. The nearer group was mostly submerged, but as in uffish thought I stood, one of the monsters raised its head above the river and smiled. “What a charming smile,” I said. “That? You are crazy,” replied The Family. She was quite upset with my suggestion that we go away to look for other animals for a while.

Hippos are territorial in water, and mark out a stretch of a river as their own. I’ve not seen a border skirmish among hippos, even in a documentary. So when a second hippo surfaced and started trying to bite the smiler, I guessed that it must be play. Hippo bloats have a single bull, but are otherwise mixed. I hadn’t seen them often enough to gauge whether these two were adults or juvenile. The fighting or play went on for a while, giving me something to photograph. The pair would spend a lot of time trying to bite and block with their jaws, but one or the other would sometimes submerge and reappear on the other side of its rival and try to bite it on the rump or side.

It is hard to believe that anything could be related to hippos, but when I found that their closest relatives are whales, I thought that it makes sense. Based on DNA studies, it is thought that Cetaceans and the Hippo lineage separated around 55 million years ago. At that time the atmosphere was 5 to 8 degrees Celsius warmer than today. It is known from fossils that hippos evolved in Africa. The oceans would have been rather high, and part of the modern range of the Hippopotamus was under water then. But what is even stranger is that hippos are (somewhat more distantly) related to antelopes, and like them have three chambered stomachs. I guess that is why hippos have to leave water to eat. It would be interesting to go on night safaris to see hippos grazing on grass.