Science - August 11, 2010

Face to face with a pygmy hippo

When Mark van Heukelum came face to face with a roaring pygmy hippopotamus in Ivory Coast, he did the sensible thing: step aside. This frightening incident was the climax during an unusual research assignment.

Got him!
Well, he did ask for this to happen. It's not normal that you get to meet a pygmy hippo, except in a zoo. These nocturnal animals are just too rare and reclusive. Van Heukelum (fifth year student of Forest and Nature Management) spent almost five months in the Tai National Park in Ivory Coast to study pygmy hippos for his graduation subject Resource Ecology.
Too many females
A layman would view a pygmy hippo as a smaller sibling of the common hippopotamus. However, they have very little in common, Van Heukelum explains. It is estimated that there are still a few thousands wandering in Ivory Coast, Liberia and Sierra Leone on a surface area of about 5000 square kilometers. But their numbers are dwindling rapidly. Breeding programmes in zoos have therefore increased in importance, so that the pygmy hippo will not die out. This has brought about a remarkable phenomena: 60 percent of the baby hippos born in captivity are female. This makes breeding difficult. One wonders if this lopsided situation also takes place in the wild. That is why the Institute of Breeding Rare & Endangered African Mammals (Ibream) has begun extensive research into the pygmy hippo. Van Heukelum and his Wageningen colleague, Henk Eshuis, are the pioneers of this research work.
Wide-opened jaws
And so Van Heukelum found himself, just three weeks after his arrival in Ivory Coast, face to face with a pygmy hippo. 'We followed a track which led to a hollow under a tree. Water levels are low during the dry season. Pygmy hippos therefore search for hollows under the root systems of trees along the water's edge. These hollows have come about when leaching occurs in the soil', he says.
'We were in luck. A pygmy hippo suddenly splashed through the water surface and headed towards me, with its jaws wide opened. It made an enormous roar and gurgling sounds and stood right in the middle of the passage. A split second later, another of its kind followed suit. Excitement mounted.  But it was sensational as well.'  Unfortunately, his attempt to capture the event failed.
The actual research work did result in beautiful images. The Wageningen students set up a systematic network of twenty cameras in three different areas six-by-six kilometers big. The cameras with motion sensors recorded all that went on, day and night. Along a busy passage, hundreds of photos were snapped within a few weeks, giving information about the appearances and behaviour of pygmy hippos.
However, the pygmy hippos only appeared on a fraction of the photos. 'An average of six hits every three weeks, for all the cameras taken together. The occurrences were very few. You therefore need to be careful when drawing conclusions from them.' The rest of the photos show many other animals. Most of these are duikers, a kind of small deer.  Some of these are very rare, such as the Jentink's duiker, which is as rare as the pygmy hippo. There are also forest elephants, chimpanzees, leopards and armadillos.'
Big toes
Besides photography, Van Heukelum also carried out other research tasks, such as examination of footprints. He recorded the breadth of the two big toes for every footprint. This original idea shows something about the age of the animals and therefore, the population buildup. It brings up new facts. 'I came across only two different sizes. I therefore have a strong belief that reproduction is linked to the seasons. Otherwise, there would also be in-between toe sizes. This season-bound idea is new, but logical. Babies can only swim after five months. It is therefore pointless to be born in the rainy season.'
Van Heukelum and Eshuis are the first and, for the time being, also the last students to travel to Ivory Coast. 'It's banned now because it's too dangerous.' But the work will continue. 'Ibream will assign a PhD student to it, but via a foreign channel.  Yes, I've been approached but I'm not sure yet. The work is tough, physically and mentally.'
See also and the weblog