It turns out there is surprisingly little evidence for life after death. I mean this specifically in the ecological sense. Think “the circle of life” from The Lion King in Mufasa’s lecture to Simba: “When we die, our bodies become the grass, and the antelope eat the grass.” Mufasa said it and we all know it, don’t we?
Well, it turns out that it’s not quite that simple. Because when we die, we don’t really become the grass. Not at first anyway. First, we become food for something, and then we become air. Note that I’m ignoring all the human practices around death. In fact, I’m assuming we’re talking about a fresh carcass deposited in the African savanna, because that’s where I work.
Photo by Ryan Helcoski.
Overcomplicating the Circle of Life
Now, as long as there is a healthy scavenger guild — think hyenas and vultures — the majority of that carcass we’re imagining is going to be eaten by large animals and the smaller bits will be eaten by invertebrates. Even the juices that sink into the soil are — you guessed it! — eaten by even smaller things like soil microbes. Inside the guts and stuff of all these organisms, from hyenas to bacteria, the proteins from the carcass are generally either broken down into their amino acid building blocks and then reincorporated into living tissues, or they are converted into glucose though gluconeogenesis.
This glucose is then combusted in the presence of oxygen within the “mighty” mitochondria, the powerhouse of the cell (I was a high school teacher for a decade, so I am legally required to complete the meme), to release their stored energy. This process, known as cellular respiration, which you may remember from high school biology, can be expressed in the formula:
C6H12O6 + 6O2 → 6CO2 + 6H2O
So when an animal dies, its remains are eaten by other living things — from lions, jackals, and carrion birds to scarab beetles, round worms, and bacteria. The material that made up the body is then either incorporated into the bodies of the life forms that consumed it — since you really are what you eat — or used as energy and released into the air.
Photo by Tom Bouyer.
But that’s fine too, since plants don’t grow out of the ground but out of the air. Yes, land plants nearly always anchor themselves to the ground through their roots, which they use to absorb water and nutrients, but the vast majority of their mass doesn’t come from the soil. They get it from the air. But you knew that already, because you remember the equation for photosynthesis, right?
6CO2 + 6H2O → C6H12O6 + 6O2
See, the majority of the mass of that glucose molecule , which plants use to build their bodies, comes from the CO2 (carbon dioxide) they absorb from the air, not from the ground. In fact, even the O2 (oxygen) they expel comes from the H2O (water) they absorb, not the CO2. That CO2 goes directly into the glucose molecule, along with the hydrogen from the water. But the hydrogen is nearly weightless in comparison to the oxygen and carbon. Thus, the vast majority of a plant’s biomass comes from the air.
this massive baobab got about 95% of its biomass from the air.
Photo by Ndzalama Mkansi.
So, the circle of life is really closer to something like this: When we die, we are eaten. We then become the thing that ate us, and eventually we become the air, and the grass eats the air as it grows. Then the antelopes eat the grass and so we become the antelope. I guess Mufasa was right after all. He probably just skipped the middle bit to make it easier for his young son Simba to understand.
Megacarcasses
But surely that can’t be all there is to it, right? It’s true that most food scraps can make excellent fertilizer if they’re composted. So, shouldn’t the same be true of a carcass? Well, maybe. A body doesn’t often get the chance to really decompose. A squirrel dies in the pines and a coyote finds it and eats it. A lizard dies in the rainforest and ants pick it clean. An earthworm dies in the soil and nematodes process its body. Even animal carcasses that somehow escape the notice of scavengers are often seen as ephemeral resource patches — short-lived and without much impact.
Granted, this isn’t always the case. Mass mortalities of reindeer impact their local environment. The mass emergence and subsequent death of periodic cicadas create massive nutrient fluxes. During annual wildebeest migrations, so many die that the biofilms that grow on the bones of their dead — not even the physical bones — account for about 24% of the diet of local fish.
And that’s not even touching the marine environment. For example, although whales that die in shallow water are often torn apart, those that sink to the abyssal zones can become “whale falls” that support whole communities of life — look it up, it’s incredible.
However, the same cannot be said for the terrestrial environment. Let’s pull back from the mass death I mentioned and focus instead on a single terrestrial carcass. If you scour the literature, you’ll find a few interesting studies that explain how moose, kangaroo, bison, or antelope carcasses do, in fact, cause measurable impacts on their native environments, mostly by increasing the nutrient content of local soil. But such studies are rare, maybe because carcasses are often pretty well eaten. But surely something bigger than a kangaroo, or even a moose, something much bigger — a megacarcass of, say, an elephant, weighing more than 1,000 kg (over 2,200 lb) — must have a measurable localized ecological impact, right? Well, the truth is … we don’t know.
A 92-day old carcass in the north of the park. Photo by Ryan Helcoski.
Which is absurd, isn’t it? At present, we do not know the fate of an elephant carcass in the African savanna. We do not, as I write these words, know what really happens to the area surrounding such a carcass. And I find this to be unacceptable. Which is why I’m here doing field work in the Kruger National Park.
In the Kruger National Park
Here in the Kruger, the elephant population is on the rise. Hyenas, lions, jackals, vultures, scarab beetles, carrion beetles, ants, bacteria, nematodes, and just about any native scavenger or decomposer you can think of are numerous. There are huge herds of water buffalo, stands of mopane, sprawling grasslands, native flowers, rare birds, endemic insects, and so much more. In fact, this massive national park at 19,485 km² is close in size to the state of New Jersey or more than twice the size of Yellowstone.
In the dry season, herds of buffalo and zebra intermingle with elephants on a sandy stream bed. It
might not look like it, but there’s water running under the sand and elephants know how to get to it.
Photo by Tom Bouyer.
And in an area that big with a healthy and growing elephant population, there are going to be a lot of dead elephant bodies. About 100 to 300 annually. By my latest tally, I’ve been to 170 of them — in fact, I’m done discovering new ones at this point. My task for 2025 is to revisit those I’ve been to and check my transects, weigh dung and bones, observe grass growth, and remove camera traps. Because my biggest question is simply: What is the ecological impact of a terrestrial megacarcass?
This, however, is too broad for one person to discover, so I’m glad I’m not alone in trying to answer it. Thankfully, there’s a whole team of researchers with me studying decomposition rates, plant nutrition, vertebrate visitation, seedling growth, the movement of bones, and many other factors. However, instead of going over all our hypotheses and what we are — or are not — finding, I’d rather take you in the field with me as we search for an elephant carcass.
Ready? Let’s go! Close your eyes and count to three. Ignore the hyperspace bypass and that sudden drop. Okay, open your eyes. You’re in the savanna now. It’s incredible. Look around you. The grass is quite high because we’re in the middle of summer. Take a breath before we get moving. The air is clean and fresh and the scent of rain lingers on the wet grass.
At the edge of the savanna, you can see tall grasses, scraggly bushes, small trees,
and a sky that’s bluer than blue. Photo by Ryan Helcoski.
There’s an absolute cacophony of insect noises and bird calls unlike any you’ve ever heard before. Earlier this morning, the lions were roaring, but they’ve quieted down now that the sun has risen. Speaking of the sun, while it feels warm and comfortable at 28°C (82°F) right now, it’s definitely going reach over 40°C (104°F) today so we have to get moving.
As we walk through the tall grasses and thick shrubs, you need to be careful not to get snagged. I’m sure you’ve noticed the numerous, but relatively small, trees we’ve passed. Some of them, like Terminalia sericea, have beautiful thick leaves while others, like the numerous species of Acacia, have much smaller compound leaves — and a TON of thorns. Lots of the plants here have thorns, spines, and spiky bits, so you have to watch your step.
An acacia thicket blocks our path, but we’ll be fine as long as we’re careful. Photo by Ryan Helcoski.
You have to be observant at all times out here. You’re not in a backyard forest or on a casual hike. You’re in the bush, and there are no trails. Make mental notes about the direction you’re walking and pick out landmarks you’ll remember for our way back. We do have to get you back to the exact location you beamed in on. Also — and I won’t sugarcoat this — there are quite a few animals out here that can kill you.
Now, that doesn’t mean that the Kruger is dangerous for tourism. Far from it. But that’s because tourists aren’t generally allowed to freely wander the bush. I got us special passes though, so we’re fine. Just stick close and stay alert at all times. Be extra vigilant in the tall grasses and walk carefully around the trees.
It’s a different world right now than in the winter. Everything is so lush and alive. Granted, it does make it a bit trickier to see the big mammals that are everywhere. The grass is so high, it’s very easy for anything that doesn’t want us to see it to keep it that way. Anyway, I know we’re getting close because I can see some scattered bone fragments. Let’s press on, and keep our eyes peeled. It looks like there could be a clearing up ahead and that’s very possibly where our elephant died.
Yes, I know the area is already mapped out. You didn’t think I’d take you to a fresh carcass, did you? No, we’ve been here before and we’ve already mapped the area, complete with rebar at the center and transects radiating outward. This elephant was a bull male who died more than a year ago. How do I know that? I actually know a lot about these carcasses. I know not only approximately when they died but also their sex, age class, the distance to water, the surrounding soil type, the annual precipitation, the distance to the nearest road, hyena and elephant density, and other relevant data.
I want to know what happens to these carcasses over time, and it’s very possible that some of these predictor variables — such as sex and age — can cause very different dynamics. For example, elephants are matriarchal. The oldest, most dominant female is called the “matriarch,” and the herd, which is comprised of females and young males, follows her.
Adult males can form groups too, but they are often wandering loners. This is significant — or it might be — because elephants revisit their dead and when they do, they deposit dung and urine, crush vertebrae, pick up bones, and even roll skulls away. These events could be ecologically significant since pulling bones away means the bones don’t decompose there, and depositing dung and urine creates an influx of nutrients.
However, it’s very possible there’s a difference in the elephant visitation rate to male and female carcasses. Since female elephants form tight-knit groups that represent many generations, female carcasses might be visited more often than male ones. And more visitation means more dung and bone movements, which could create different ecologies.
An elephant died here about 400 days ago. We think that, over time, the nutrients deposited in this
area will result in increased plant growth. Photo by Ryan Helcoski.
If these sites really are ecologically significant, which we think they are, soil type likely plays a role. Basaltic soils can hold nutrients longer than granitic. And though you can probably guess the role we think hyena density plays — more scavengers mean more things to eat the meat — precipitation may also matter because more water means more nutrients leaching out of bones and into the soil.
If you’re at all statistically inclined, you know that with the sample size I’ve described, I’m not entitled to so many predictors. This research is still preliminary — you caught me in the middle of it. The point is that there are many factors — both biotic and abiotic — that could influence the ecological impacts of a single carcass. And there are a lot of these carcass sites in just this one park.
Heading Home
Alright, we need to head back now. The temperature is still rising and we’ve got to get you home before dusk. But as we walk, I’d like to tell you a bit more about what I’m studying and why. At the most basic level, I’m asking a question about how nature works. Specifically, I want you to look for heterogeneity — essentially, differences in the environment. Look at how the rocky outcroppings support different plant species than the flooded areas do. Notice how sometimes we’ll walk through a grassy area with few to no trees, and other times we have to carefully pick our way through thorns. We think that elephant carcasses might be another driver of this heterogeneity. Probably not a very big one compared to things like precipitation and elevation, but one that likely contributes to both the intricacy and functioning of nature.
And this matters because although nature will always work — it worked through the Permian extinction, when over 90% of all species died — how it works is what matters most. Remember in the beginning when I was talking about the cycling of matter? Cellular respiration and photosynthesis? There’ll be a quiz at the end.
Matter has been cycling on this planet for a very long time. You and I are made up of some of the same chemicals as the dinosaurs, the plants around you, and the stars. I want you to know that this matter will continue to cycle on our planet no matter what we do or how poorly we manage it. But how it cycles can make a world of difference.
A stream in the Kruger National Park. Photo by Tom Bouyer.
Remember when I talked about the circle of life and how the bodies of the dead are incorporated into the bodies of the living and then released into the air? What if you take the scavengers out of the equation? Remove the hyenas, vultures, and lions. In some parts of Southern Africa, where predators and scavengers have been nearly wiped out but elephants still roam, elephant carcasses are primarily scavenged by bot flies. Researchers who work there have described scenes of rotting, oozing flesh that can be smelled kilometers away, and fly larvae so numerous that they pulse and drip within the bloated bodies that persist for much longer than our carcasses. Mercifully, I don’t have a picture of this.
Either way, a carcass is being eaten. Matter is being cycled. Now, I don’t know about you, but I prefer the cycle where hyenas and vultures and elephants play an active role in nutrient dispersal to the one dominated by bot flies. Regardless, nature is working in both cases. And it will continue to do so long after we are all gone, no matter what state we leave it in. Perhaps the bigger question is: Who cares or does it even matter?
Well, it does to me. And I hope it does to you too. It looks like we’ve made it back to the spot where you beamed in. Time to depart the savanna and head back. It’s been a nice trip and I’ve enjoyed spending this time with you. I hope our time together was informative, or at least interesting.
And remember that when you get back, even if you’re just sitting in an office or reclining on a sofa, you’re still part of this whole cycle of life. You’re cycling matter right now. No matter how removed from nature you might feel, you’re still a part of it.
And you always will be. No matter what.
Sunset over the Kruger National Park. Photo by Tom Bouyer.
