There is no better time to realize the importance of water to the bush than winter. Aerial views of waterholes reveal a busy network of dusty game trails converging on this valuable resource and with water being in short supply during the dry winters it is no wonder they are often a hive of activity. However, it is not only the land dwelling creatures that rely heavily on these water sources during winter but also two of our favourite large aquatic animals, namely Hippos and Crocodiles.
It is not an uncommon sight to drive past one of these waterholes in winter and see large numbers of hippos basking in the sun on the bank, and in between them in close proximity a few Nile crocodiles doing exactly the same thing. It is a sight that confuses a few people and begs the question as to what exactly the nature of the relationship between these two impressive looking animals is. It is not only winter times that hippos and crocodiles come into contact with another but because the river starts to dry up and waterholes begin to shrink it is often in winter that these interactions become more frequent.
For it to be considered a friendly relationship one would have to assume that they have a mutually beneficial symbiosis in which both parties help the other one out in some way. There may be some cases where this has inadvertently been so, but would be the exception rather than the norm. The fact that both of them can exist quite happily and easily without the presence of the other suggests that symbiosis is not an explanation to the nature of their relationship.
But when looking at pictures of them right next to each other it doesn’t look as though they are enemies either. For hours on end we have witnessed hippos and crocodiles lying mere metres apart without even a sideways glance from either party, neither species looking at all fazed by the presence of the other. When one considers their respective diets, it all starts to make sense.
Hippos are herbivores and need large amounts of grass to graze on in order to sustain themselves, but crocodiles are carnivores and will eat fish as well as any unsuspecting herbivores that come down to drink at the water. Therefore, crocodiles are predators and hippos are effectively prey so how come they lie next to each other in peace around a waterhole?
The reality is that given half a chance a crocodile would attack and feed on a hippo but they do not because of just how dangerous a hippo can be. An adult hippo needs only to open it’ mouth wide and reveal its mean-looking modified incisors or tusks to drive home this point, and combined with its size and tough skin they are not an easy target. The average sized adult crocodile is no match for the average sized adult hippo, and considering that hippos are often found in pods with numerous other adults it’s not worth it for a crocodile to even go after a young hippo because of what the protective adults could do to it.
As a result they live together in a bit of a stalemate with both parties fully aware of what the other is capable of, and with survival being a big motivating factor they tend to stay out of each other’s way despite living together in the same environment. Yes, there are plenty of documented cases of them attacking one another but considering that they live in the presence of one other for the majority of their lives this is bound to happen on the odd occasion.
For the most part of it though their relationship is one of coexistence with not much interaction due to their inherent survival instincts.