I assume it varies by species, but I initially got to thinking about it in looking at these online videos of the great herd animals in Africa - wildebeests, zebras, buffalo etc. - which are prey to lions, hyenas etc. What percentage of these animals ultimately end their lives being torn apart by a predator, versus dying of old age? Do virtually all of them eventually get eaten (mostly when very young, or when older and sicker) or do a substantial percentage die peacefully, surrounded by loved ones ?
The same question also applies to predators. Most of these species reproduce at a much greater rate than 1:1, so if their population were to remain stable, something must be happening to a lot of them along the way. But what is it? I know some baby lions are killed by other lions (especially if a new male takes over), but is that the majority? I once read, in a book of animal pictures, in the caption of a picture of a solitary male lion past his prime, that his ultimate destiny was to be torn apart by wild dogs or something similar. Is something like this the typical fate of old lions (or hyenas, crocodiles, whatever)?
Again, I understand that it varies by species, but I’m interested if the answer is known for some of the more common species.
If you’re a wildebeest, then you are too weak and slow to evade lions for a long time before you die peacefully with your friends standing around. You may also be too slow to even keep up with the herd, which is your only real protection from the lions.
In nature, predators tend to pick off the weaker members - the youngest and the oldest - so this is going to be true for most prey species.
I suppose there’s a good chance of dying from exposure, dehydration or starvation if you happen to become injured, sick or weak when there aren’t predators around. I’m sure this would be the norm for most predators, some of whom might starve just by being unlucky.
Large herd animals such as wildebeest and zebras will almost certainly be killed by predators rather than dying of old age, at least where large predators are common.
Elephants are almost invulnerable to large predators as adults. They will also be protected by their herd mates, and so have a reasonable chance of dying of old age. This may possibly be the case for a few old rhinos or hippos as well.
Where herbivores greatly outnumber their predators, such as White-tailed Deer in much of North America, many individuals may die of disease, malnutrition, or severe weather without being preyed on.
Large open-country predators like lions are likely to fall prey to other predators when they get old or sick. However, predators like tigers or bears that use dens may hole up when they are sick or starving and end up dying on their own without being killed.
Most small animals also fall prey to predators, but those with nests or dens may end up dying there if sick or starving.
Or being hit by cars. The main predator species for White-tailed Deer in North America is the human hunter, and every year more deer are killed by cars than hunters.
I once read or heard that most elephants that manage to survive into old age will eventually starve to death. They outlive their teeth. With no teeth they can’t eat.
I had thought that hippos were almost impervious to predators because they mostly live in the water and are too big to be taken by crocodiles.
Which other predators? And how do these predators figure out that a particular lion is old enough for them to take on? Because if they guess wrong that might not end well for them, and it might be safer to try their luck with a warthog or something.
[While on the subject of dens, your post implies that lions don’t live in dens, and this is consistent with everything I’ve read or seen of actual lions. But the concept of a “lion’s den” is so widespread and well known that I would have to think there’s something to it. What gives?]
With advanced age, moose will also wear their molars down enough to stop being able to eat, leading to death by starvation in a predator-free environment.
Probably the most significant predators on adult lions are Spotted Hyenas. Contrary to their image as cowardly scavengers, hyenas are powerful and ferocious predators that frequently drive lions from their kills and even kill them. Here are a couple of videos of hyenas driving adult lions from kills.
An old or sick lion is likely to be emaciated due to inability to hunt well. It will be easy enough for hyenas to detect when one is vulnerable.
Once when I was camped in Samburu National Park in Kenya at night a battle royal between a pride of lions and a pack of hyenas broke out a few hundred yards from my tent. I didn’t get a lot of sleep that night.
Lionesses may use dens to give birth if they are available. And when lions used to occur in more temperate areas of Europe and Asia they might well have used dens more habitually.
I had seen some of those. But has anyone ever documented hyenas killing a lion?
Which brings up another question. You see a lot of videos in which the human observers are viewing predatory animals, and filming their attacks, from open vehicles. Why are they so sure they won’t themselves be attacked, and what’s the Plan B if that certainty turns out to be wrong?
For whatever reason, as far as I know predators will rarely attack humans in a vehicle. While I can’t speak from personal experience, I would guess that film crews mostly likely have a firearms available for emergencies.
On Jeopardy, a few years back, there was a Final Jeopardy answer that was this very fact. The answer was something along the lines of “Elephants live to about 60* years, until these wear out.”
The correct question, of course, was “What are teeth?”
One contestant, however, chose the question “What are feet?,” to which Alex responded with a laugh, that yes, when they get down to about two feet high, they die.
Zev Steinhardt
I don’t remember the actual number used in the answer
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