On one of my ministry trips to Africa I observed hippopotamus footprints along the banks of a river. My guide told me that as soon as the Sun drops low in the sky all the hippos exit the river and spend the evening, night, and dawn hours foraging for food on the land. As soon as the Sun rises much above the horizon, they return to the river once more.
This day-night behavior cycle is critical for hippos’ survival. The ratio of their body mass to their skin surface area is so high that they would overheat during the day unless they remain submerged in the water. Furthermore, their skin is easily sunburned. Thus, hippos seek maximum protection in muddy water deep enough that they can submerge their entire bodies except for the tips of their nostrils.
This behavior, combined with their ornery and highly territorial nature, makes hippos extremely dangerous to humans. Job 40:15–24 describes the behemoth, likely the hippopotamus, as one of most dangerous and difficult to tame nepesh (soulish) animals. Hippos remain so well hidden in Africa’s rivers and lakes that boaters, swimmers, and people doing laundry often don’t realize they have invaded hippo territory until it is too late. To make matters worse (for people at least), crocodiles like to hang out just outside of a hippo’s territory, knowing that if they are patient, the hippo, itself an herbivore, could serve up a free meal.
An understandable reluctance to conduct intensive field research on hippos has, until now, caused biologists and ecologists to miss an important design feature in the African ecosystem. But researchers have recently discovered another important component of hippo behavior: adult hippos defecate an average of 8 kilograms (18 pounds) per day while in the river.1 The excrement sustains huge populations of microbes, which make up the base of the aquatic food chain. In this way, hippos literally support an entire aquatic ecosystem. Their waste transfers important nutrients from the land into the water systems and significantly enhances the biomass and biodiversity of African wildlife and foliage.
This discovery also demonstrates God’s wisdom in designing hippos the way He did. It seems God purposely made these giant mammals sensitive to overheating and sunburn so that they would spend much of their time in water, thus allowing appropriate amounts of nutrients to be transported from the land to lakes and rivers.
During biblical times, hippos inhabited a much larger habitat range. Job 40:23 describes hippos residing in the Jordan River (see my book Hidden Treasures in the Book of Job for more on this passage of Scripture). Now hippos are listed as vulnerable on conservation status lists. Given the important role hippos play in sustaining aquatic ecosystems, we would be wise not only to put an end to hippo poaching but also to help restore their populations and habitat ranges to their previous sizes.
- Elizabeth Pennisi, “The River Masters,” Science 346 (November 14, 2014): 802–5.