When a pair of hippopotamuses came to rescue a wildebeest about to be a crocodile's lunch, people were quick to think that it's another case of animal altruism. However, it's more likely that this isn't entirely true.
Are animals capable of altruism in the first place? The answer to that isn't as clear-cut as we'd like. There have been reports of animals behaving in an altruistic manner toward other animals and even humans, but many of these reports were made by casual observers, not animal behaviorists.
This doesn't mean that animals can't be altruistic. That is still a possibility. However, it's still safer to assume that animals act to serve their own interests. It's rare for animals to risk their own safety or interests to come to the aid of another. There was a case of humpback whales fighting off a pod of orcas to save other whales, but even this wasn't a clear-cut case of altruism.
And he would have gotten away with it, too, if it weren't for those meddling hippos!
So what happened with the hippos “saving” a wildebeest from a crocodile? A couple touring the Kruger National Park in South Africa came upon a watering hole, where a crocodile had just bitten a wildebeest. The wildebeest fought to get free, but the crocodile kept a firm hold on the other animal's leg. This struggle continued for about eight minutes, after which the wildebeest appeared to tire. The crocodile then began to slowly drag the wildebeest into the water, where the crocodile has the advantage over its large prey.
As the crocodile proceeded to pull the wildebeest further into the water, two hippopotamuses appeared. They charged towards the crocodile, causing the reptile to lose its hold on its prey. The wildebeest managed to get free, though having a broken leg doesn't bode well for its survival.
The question, of course, is whether or not this was a case of animal altruism. Did the hippos see a wildebeest in distress and decide to help it? Probably not, says Douglas McCauley, a professor at UC Santa Barbara. McCauley says that the hippos actually acted in their own interests, which coincidentally resulted in the wildebeest getting free. Thus, it's unlikely that this was a case of animals showing altruism.
Don't mess with these guys
McCauley has two theories two explain why the hippos did what they did. The first is that the crocodile may have been hunting a little too close to the hippos' territory. Hippos are herbivores, but they can be quite aggressive and territorial. Generally, hippos and crocodiles stay away from each other. However, hippos lash out if crocodiles get too close.
The second theory is that the hippos heard the wildebeest thrashing in the water, prompting them to come stake their claim on their territory. McCauley himself is leaning more towards this theory, knowing that hippos are territorial and tend to be aggressive in defending their territory from interlopers.
Thus, it's unlikely that the hippos that the hippos were rushing to the wildebeest's aid. In fact, they were likely rushing over to kick both the crocodile and the wildebeest out of their territory. This may not be animal altruism, but it's an interesting example of how animals interact in the same space.
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