In the heart of Africa’s diverse ecosystems, the mighty hippopotamus emerges as an unexpected yet influential force shaping the environment. While often recognised for their imposing size and semi-aquatic lifestyle, hippos hold a lesser-known title as ecological engineers, contributing significantly to the intricate balance of their habitats.
Robyn Morrison has touched on this topic previously, with a specific look at elephants and rhinos. I wanted to take a closer look at another large herbivore who slides under the radar as being a significant environmental architect of what we see at Londolozi.
Ecological engineers are species that greatly modify their environment, influencing ecosystems and biodiversity. Hippos, primarily found in sub-Saharan Africa’s waterways, play an integral role in shaping both aquatic and terrestrial landscapes.
The existence of hippos as both aquatic and land-dwelling mammals is key to their engineering ability. During the night, these semi-aquatic animals move towards the land, grazing on grasses and other vegetation. This grazing behaviour not only sustains their massive size but also shapes the landscape by trimming vegetation, thereby affecting plant growth and species diversity.
On average, hippos eat about 40kg of food each night, which is about 1 to 1.5% of their body weight. This feeding is done in about 4 to 6 hours of the night when the hot sun is not scorching down on their sensitive skin.
The true impact of hippos, however, becomes most evident during the day. As the day heats up, hippos head back into water bodies, seeking shelter from the sun. While submerged, they engage in a distinctive activity that earns them their ecological engineering badge – defecation.
Hippo dung, a blend of digested grasses, is launched into the water, providing vital nutrients to aquatic ecosystems. These nutrients, including nitrogen and phosphorus, enrich the water, stimulating the growth of algae and other microorganisms. In turn, this abundance of life becomes a primary food source for various aquatic species, from fish to invertebrates, forming a complex food web.
Waterholes become nutrient hotspots for vegetation due to the nitrogen deposits from the hippo dung. This helps common plants like Ludwigia (the aquatic plant above) to grow in abundance.
Moreover, their dung acts as a natural fertiliser, often carried downstream by currents, benefiting flora and fauna along the riverbanks. The deposition of hippo dung results in nutrient hotspots, promoting vegetation growth and fostering diverse habitats for other animals, thereby enhancing biodiversity in these riparian zones.
Interestingly, the very act of hippos wallowing in the water also contributes to their ecological impact. Wallowing creates depressions in riverbeds, forming small pools. These pools provide shelter for other aquatic organisms during dry seasons when water levels recede, thereby ensuring survival during harsh conditions.
By heading to the Causeway, you will be surrounded by hippos and all other species around them. It’s not uncommon to see various other animals using the hippos as platforms in the water, such as herons, hammerkops and terrapins.
The hippopotamus, with its large presence and seemingly simple lifestyle, stands as an unsung hero in African ecosystems. Through their seemingly mundane activities of grazing, defecating, and wallowing, these charismatic creatures sculpt landscapes and foster biodiversity, earning their rightful place as nature’s under-appreciated ecological engineers.
Who would have thought that the hippo would play such an important role in ecological engineering?! Thank you Ross for your informative blog.
Ross thanks for the information about the hippos role in ecological engineering. Massive animal with a huge appetite creates interaction among the plants and animals around all of the waterways, fascinating.
Thank you Ross! Hippos have been among my favourite animals since childhood. I often wondered why they were not contemplated in the “Big crew”. I recently watched a fantastic documentary, Hippo King, it was very funny as the main character was a male hippo followed from his birth to his death, passing through his dangerous life as a calf to his short friendship with a leopard to his kingdom. What was most interesting was the way Hippos are responsible for the shaping of rivers and their maintaining. They are fantastic animals and a link between two worlds. You wrote about their abilities in a skillful way, I’m always so pleased by the writing skills of Londolozi bloggers!
Well know Ross, that is interesting information you have explained to us. Hippos being the ecological engineers and adding biodiversity. We have so much to learn from nature and to be appreciative of nature.
Thanks, Ross, for this enlightening article on Hippos. Normally they are seen as just a species among others, an interesting one, sometimes entertaining to watch, but not as important, as, e.g. elephants. However, as you point out in this blog, nonetheless very important for the ecological system. I always like seeing birds or turtles a.s.o using hippos as a vantage point of means of transport. It looks so cute.
Loved learning more about hippos, thank you!
Thanks for that, Ross. Despite seeing many hippos during my visits I really had no idea of the importance of their role.
Brilliant and informative post Ross!