How Do Animals Understand Death?

KATHLEEN DAVIS: This is Science Friday. I’m Kathleen Davis. Throughout history, humans have given a lot of thought to death. We grapple with the inevitability of mortality, we create elaborate burial rituals, and we decide how best to mourn the loss of a loved one. But what about other animals? How do they understand death?

Joining me now to help answer that question and more is my guest, Dr. Susana Monsó, author of Playing Possum, How Animals Understand Death. She’s also associate professor of philosophy at the National Distance Education University in Madrid, Spain. Dr. Monsó, welcome to Science Friday.

SUSANA MONSO: Thank you so much for having me. It’s a pleasure to be here.

KATHLEEN DAVIS: So I want to jump right in and talk about the animal that’s in the title of your book, which is a possum, or as they’re sometimes called, opossums. What’s so special about possums and their relationship with death?

SUSANA MONSO: Yeah. So the opossum is an animal that I find really fascinating. Apart from the fact that they’re super cute, in my opinion, the opossum, when she feels threatened and she feels like she cannot escape, she pretends that she’s dead, but she does this in an extremely elaborate way.

So she adopts the bodily and facial expression of a corpse. Her body temperature drops, her breathing and heart rate are reduced. She expels this putrid smelling liquid from her glands, and she stops responding to the world. She also opens her mouth and her tongue hangs out, and it adopts this bluish hue. So it’s a very, very elaborate ritual.

If you don’t know ahead of time that she engages in this little trick, you would be fooled by her for sure. And the opossum is in the title of my book because I think the opossum gives us some clues for how animals understand death. And this is not because the opossum, herself, understands that she’s playing dead. I think that for the opossum, this is probably an automatic reaction, like when our pupils dilate or our hair stands on end when we’re afraid, her display tells us something about how the predators that she’s trying to deceive understand death.

So in order to understand this, I think it’s helpful to think about the peacock’s tail. So the peacock has this beautiful, gorgeous, enormous tail that is very problematic to have in a lot of regards, because it makes it more difficult to fly and to run away from predators. However, they have this tail because the peahens love it.

And so the tail tells us something about the peahens’ mind. It tells us what she finds sexy and something similar can be said of the opossum’s death display. It’s not that. It’s telling us something about the opossum’s mind, but rather it’s telling us something about how her predators understand death. It shows us that they think of dead individuals as having a certain facial expression and bodily posture, as being cold, as showing no signs of breathing, smelling bad, not responding to the world, et cetera.

So the opossum’s display gives us a window into the minds of her predators. It shows us how they understand death.

KATHLEEN DAVIS: So in your book, you write a lot about this thing called the minimal concept of death. Tell me a little bit about what you mean by that and why it’s important to define when we’re talking about animal’s understanding of death.

SUSANA MONSO: The question of whether animals understand death is one that requires us to first define what exactly we mean by understanding death. And more often than not, this notion, the concept of death has been understood in very demanding ways. The question has been construed as, do animals have a concept of death that is equivalent to the human adult’s average concept of death.

So one that entails an understanding of the concept of absence, of infinity, of abstract thinking. I think that understanding the question this way, on the one hand, is a little bit unfair because that’s not usually how we pose the question when we think about human children. Human children don’t acquire a concept of death overnight, rather it’s something that takes them a while to develop. It takes them several years before they fully understand death.

If you’ve ever played Super Mario Brothers with a six-year-old, you will know that they do grasp something about death. So we’re setting a double standard if we’re asking the question in different terms when thinking about children and thinking about animals. But also, I think that construing the question this way just makes it a not very interesting question. If what we mean when we ask if animals can understand death is whether they have anything equivalent to the human adult average concept of death, the answer is going to be no. And that would have made for a very short book.

So it’s more interesting, I think, to ask, do animals have anything that counts as a concept of death? And for that, what I do is, I begin from what I call the minimal concept of death, so the bare minimum that an animal would need to understand in order to be credited with some understanding of death. And the minimal concept of death, basically, just amounts to the idea that dead individuals don’t do the sorts of things that living beings do and that this is an irreversible state, so that once you’re in this state, you cannot go back to being alive.

And so the idea is, we start from there, and then we can look into how complex animal’s concept of death actually is.

KATHLEEN DAVIS: So let’s start with some of the smallest examples of creatures in your book. I was really fascinated to read about ants. So ants will try to save a fellow ant who is trapped, and they’ll remove dead ants from their nests. But you also say that they don’t actually seem to understand death. So explain to me what this means.

SUSANA MONSO: In the case of ants, exemplifies what I call stereotypical reactions to death. So these are reactions to death that are kind of pre-programmed, so to speak. So the animal doesn’t need to learn them or acquire them, but rather, evolution has programmed them into the animal’s behavioral repertoire. So these reactions are triggered whenever the animal senses certain stimuli in her environment.

So for instance, when it comes to ants taking out of the nest, their dead nest mates, this is something that presupposes their capacity to tell live ants apart from dead ones. But we know that there’s no concept of death involved because this behavior of theirs is very dependent on the presence of certain cues in the environment, such as certain chemical elements given off by decomposing corpses.

An example of this is oleic acid. So if you take some oleic acid and you put it on a piece of leaf or a little pebble or even a live ant, the ants are going to treat it like a dead ant, and they’re going to pick it up and take it out of the colony. So this shows us that they’re not really understanding what being dead means. They’re just reacting in a way that they can’t really help to certain cues in their environment.

KATHLEEN DAVIS: That’s fascinating. So let’s pivot to talk about our closest relatives, which are primates. What do we know about their understanding of death?

SUSANA MONSO: So I have to say that the research here is still very young, and we’re still only just starting to ask these questions. So we don’t have any real certainty here about how exactly they understand death. However, we do have certain important pieces of evidence. For instance, in the case of chimpanzees, what we see is that there is huge variability in how they react to death.

So for instance, there was a very famous case that came out about 10 years ago, where an adolescent male had died and the scientists documented the reactions of the remaining group members to the corpse of this individual. And what they found was huge variability in their reactions. So some of them sat around the corpse and looked at it or inspected it in different ways by touching it or sniffing it.

Others reacted aggressively, hitting the corpse or engaging in dominance displays. And there was also one female who stayed behind once the rest of the group had left and started to clean the teeth of the corpse.

So this doesn’t tell us necessarily that they understand death, but it does tell us that it’s something very different from the case of the ants, because what we’re seeing here is what I call cognitive reactions to death. So these are reactions that involve the psychology of the individual, her emotions, her personality, her life history, her beliefs, her desires, and so on. And that’s why we can’t predict in advance how they’re going to react.

Apart from that, a lot of primates, we see a lot of interest towards corpses. We see a lot of what looks like grief, so a lot of clues that suggest that they may have an understanding of death.

KATHLEEN DAVIS: So since chimps are so closely related to us, could they be having similar responses to death as we do, as humans do?

SUSANA MONSO: So in the literature, very often, scientists have argued that what we see in chimpanzees are behavioral reactions that are analogous to a lot of the human behavioral reactions to death. However, I think this is a little bit of a dangerous road to go down. We have to be wary of what I call emotional anthropocentrism.

So the idea that the only emotional reactions to death that are worthy of our attention are human-like reactions, because some of the reactions to death that we see in other animals are very difficult to make sense from a human perspective, at least from the perspective of Western contemporary societies. So we often see reactions like cannibalism or necrophilia that would be very problematic to see in our societies.

And so this may lead us to somehow conclude from that they don’t understand death because they don’t respect corpses the way that we do. But that, for me, doesn’t really follow, because there’s one question, which is, can you understand what death means? Can you understand the finality of it? Can you understand that individuals cannot come back to life?

And a different question is, do you react to death the way a human would react? For instance, do you react with grief? Grief, for us, is like the paradigmatic emotional reaction to death, but it doesn’t necessarily follow from understanding that someone has died, that you’re going to grieve them.

So for instance, when Amy Winehouse died, I could understand that she wouldn’t be producing any more music, but I didn’t necessarily grieve her, even though, of course, I was sad. As an Amy Winehouse fan, I was sad that she died. But I didn’t grieve her because I didn’t have the sorts of emotional bond that you need to have towards an individual in order to really be set to grieve their loss.

KATHLEEN DAVIS: Right. I have certainly seen videos on the internet, for example, or have heard stories where people definitely put that emotion of grief onto animals, whether it’s deserved or not. For example, I’ve certainly seen videos of elephants that seem to be having a deeply emotional response to a dead elephant in their group.

Or there are people who will have two pets who grow up together and then one of them dies. And then the other one seems to be really melancholy and actually, be quite sad. But is there any sort of scientific proof that these animals are experiencing grief?

SUSANA MONSO: I mean, the word proof is a very strong word, and it’s very rare that in science, we get proof of things, but it’s certainly, a well-supported hypothesis. We do have a lot of evidence that animals grieve. Anthropologist, Barbara King, for instance, wrote this beautiful book called How Animals Grieve, that has a lot of stories of animals grieving.

And I think it’s a super important topic, and it’s definitely something that we need to pay attention to, especially because it has very important ethical implications. If animals do grieve, it has implications for our treatment of them.

However, the problem is that if we’re only focusing on grief, then we’re potentially missing out on many other dimensions of animal’s relationship with mortality. A very important dimension, for instance, is one of violence. Very often, death in the natural world is something that animals cause on purpose. And very often, death for animals is not a loss, but a gain.

And if we’re only talking about grief, then we’re only talking about contexts where death is a loss, which is going to be something that happens very often and it’s a very important question, but it’s not the full picture, because, very often, death is going to be a gain.

KATHLEEN DAVIS: So for a long time, scientists and philosophers didn’t think that animals could possibly understand death or conversely, that it wasn’t worth studying. So what has changed?

SUSANA MONSO: Well, I still think that a lot of philosophers think that, and a lot of scientists think that. So I’m not so sure that that much has changed, but it’s certainly starting to garner attention. I think one of the reasons why scientists are starting to ask this question has to do with the cognitivist revolution.

So this is something that started to happen in psychology in the ’80s where there was this reaction against behaviorism, this dogma that we shouldn’t be discussing the minds of animals and we should just be describing their behavior. So once scientists got rid of behaviorism or they left it behind, they started to ask questions about the minds of animals, and they started to ask questions about the capacities that animals have.

But still, there’s a lot of fear of falling into anthropomorphism and attributing human-like qualities to animals in an unwarranted way. But at the same time, the evidence has just started accumulating, and there have been more and more cases that biologists in the field have just happened to stumble upon. And at a certain point, the number of cases became so big that they could no longer ignore it.

And so this new discipline, comparative thanatology, was born about a decade ago. And it’s starting to gain a lot of traction, as more and more people have started sharing the data that they’ve gathered.

KATHLEEN DAVIS: Well, there is clearly so much to talk about here, but unfortunately, we’ve run out of time. But I’d love to thank my guest, Dr. Susana Monsó, author of Playing Possum, How Animals Understand Death. Dr. Monsó, thank you so much for taking the time to be with us today.

SUSANA MONSO: Thank you.

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