EPOW - Ecology Picture of the Week

What Hippos Do

Hippopotamus (Hippopotamus amphibius), Family Hippopotamidae
Masai Mara, Kenya, Africa

Explanation:  Sure, they're ornery, loud, and corpulent ... and they fight for territory and make boating dangerous ... but what else do hippos do?  In particular, what important ecological roles do they play in their ecosystem?

The main photo this week provides a clue to one of their roles.  

This hippo looks very stylish with some greenery behind the ear ...
but there is more to this scene than fashion.

One major role is dispersal of vegetation among the pools they inhabit.  And not just local native plants ... as these photos show, hippos are quite adept at (inadvertently) distributing water hyacinth, a noxious and invasive aquatic weed that quickly reproduces to choke out wetlands and waterways.   
  

A hippo traveling among summer ponds in South Luongawa National Park
in Zambia, Africa, inadvertently transporting a load of Ipomoea or
morning glory, another invasive aquatic plant.
Hippos also likely are important dispersers of native plant species, too.

Another key ecological function of hippos is noted in the following photo:

Like many large terrestrial ungulates, hippos will stir up insects as it grazes and moves through grass, thereby providing other species -- such as the cattle egrets show here -- with access to food.  Egrets and other birds will follow the hippos around for access to snacks.  
  

Another ecological role played by hippos is revealed by their main habitat:

Hippos tend to wallow in muddy pits and dig out and maintain waterholes and pools.  These are critical habitats, especially during summer drought periods, for a wide variety of other wildlife.  

Further, as shown in the upper left photo above, hippos also create terrestrial pathways and aquatic waterways between the pools, and these corridors are used by many species of antelope, mongoose, and other wildlife to travel among the water holes.  
  

So next time you encounter a hippo -- for real, or in some video -- remember all the major and important ecological functions that this mountain on legs performs!