I’m one of those people—and I dearly hope I’m not the only one—who sometimes thinks in headlines. Especially when I do stupid things. Whereas others might think, “Oh, s__t!” or other profane thoughts as such times, the headline “Bureau pins local resident at bottom of stairs” occurred to me when I foolishly thought I could prevent a very heavy piece of furniture from descending a steep staircase much faster that I could prevent it from doing so by holding it from below. Or how about “Local woman picking berries in nightgown gets surprised by bear”?
In retrospect, I think this predilection may have played a role in my fascination with plant and animal behavior with their seemingly infinite ability to amaze. Let’s face it, a headline such as “Giant rat kills predators with poisonous hair” does smack of sensationalism, doesn’t it? It’s just the kind of thing I’d expect to read on the cover of some smarmy publication as I waited to check out at the grocery store.
But this was, in fact, a true account of a real species of rat that does kill its prey using poisonous hair. Better yet, I could read about it as if I was only interested in its scientific merits because there were no articles about Elvis sightings or ads for strange sexual enhancement products around it to suggest this might not be the case. The rat gains further tabloid credentials because, in addition to having killer hair, it’s also a giant rat as rats go—12-14” long—and has a crest or mane that would give a Chinese crested a run for his money. Kind of cute in a way, if it wasn’t for the hair. Hopefully no Chinese crested would decide to sample a chunk of crested rat back, though, because the poison in those hairs is capable of killing an animal bigger than an averaged sized dog, let alone one that small.
Crested rats get their poison by chewing on poisonous bark and then licking specially adapted hairs along their spines which are capable of absorbing and holding the toxin. Like other animals who borrow poisons from other sources, the goal isn’t to kill off all predators. The goal is to keep them from attacking at all. No matter how horrible the consequences of an anti-predatory display may be for the predator, it does the prey no good if they sustain debilitating injuries or die in the process. In order for such strategies to be worth the energy that goes into their creation and implementation, enough predators must survive an encounter to spread the word that it’s a bad idea to prey on the poison-carriers.
Another variation on this theme occurs in monarch butterflies who are much more common in my area than crested rats, thank goodness. Monarchs borrow their poison from various milkweed species which give them a taste their avian predators find distasteful. As with the crested rat, the success of the monarch’s strategy depends on enough predators having a negative encounter to warn others to stay away. But because of the monarch’s smaller size, shorter lifespan, and fragility, this may result in the death of some to save others.
But the story doesn’t end there for the monarchs. Another butterfly, the viceroy, appears very similar to the monarch, except for one critical difference: they’re not poisonous. But whereas the success of the monarch’s strategy depends on predators having a negative experience with one of them and then staying away from the rest, the viceroy’s success depends on predators sampling a monarch or two. If the predator munches on a viceroy first, it will keep doing so until it encounters a monarch. Only then will it be more likely to steer clear of both species. On the other hand, if the predator tries to eat a monarch first, the resulting taste aversion will protect the viceroys, too.
But even though this might seem like a good deal for the viceroy, it has its limitations. In order for them to succeed, their population must either remain smaller or appear later than the real deal. If they appear after their poisonous partners, their timing has to be perfect. Viceroys who delay too long may discover that predator’s memory of the distasteful encounter with a monarch has faded. Or a new generation of younger predators who never had a negative encounter with a monarch may have matured who would prey on them without fear.
Poison-borrowing and their mimicry are just two of the many strategies that make up the anti-predator repertoire, each and every one of them worthy of a sensational headline. But naturally, this got me thinking: Do we see corollaries of these behaviors in companion animals?
My initial response to this was no for two reasons. One is that the very nature of domestication prepares them for a life of dependency. It didn’t benefit domestic animals to possess specialized structures that could be used against humans. Those who demonstrated any move in this direction were most likely eliminated. As a result the domestic species repertoire of physical defenses is pretty much limited to teeth, nails, claws, or hooves, all structures animals used for other functions that carried more benefits than costs to humans. These included doing tasks such as keeping buildings and fields vermin-free, herding sheep or cattle over rough terrain, or pulling farm implements or carriages.
The second reason I suspect we don’t see specialized anti-predatory displays like those of the crested rat or monarch and viceroy butterflies in domestic animals is because these require generations to evolve. And this requires that those who most successfully deal with any life-threatening problems in a particular physical and mental environment survive long enough to pass that potential on their their young who then do likewise. Breeding animals with the greatest probability of success in the companion environment has not been a top priority in the United States for the last half century. Quite the contrary, the goal has been to prevent successful companion animals from reproducing at all.
As a result, increasingly Americans must select their animal companions from among those selected by other humans to survive in field or show ring, or those self-selected to survive on the streets, in the woods, or in other non-companion environments. Even if they do survive in a companion environment without these genetic advantages, the probability that they’ll be allowed to retain the reproductive capacity to pass that potential on to future generations is about nil.
The good news is that we probably don’t have to worry about dogs or cats with poisoned fur or other sophisticated anti-predatory skills cropping up in the pet population. The not-so-good news is that the fewer generations of solid breeding for the physical and mental soundness necessary to be successful animal companions, the less accurately we can predict how those animals will respond in our environments at all.
But in the meantime, who knows? Maybe sometime in the future a mimic of the crested rat will be discovered, too.
If you have any comments regarding subject matter, favorite links, or anything you’d like to see discussed on or added to this site, please let me know at mm@mmilani.com.
I’m one of those people—and I dearly hope I’m not the only one—who sometimes thinks in headlines. Especially when I do stupid things. Whereas others might think, “Oh, s__t!” or other profane thoughts as such times, the headline “Bureau pins local resident at bottom of stairs” occurred to me when I foolishly thought I could prevent a very heavy piece of furniture from descending a steep staircase much faster that I could prevent it from doing so by holding it from below. Or how about “Local woman picking berries in nightgown gets surprised by bear”?
In retrospect, I think this predilection may have played a role in my fascination with plant and animal behavior with their seemingly infinite ability to amaze. Let’s face it, a headline such as “Giant rat kills predators with poisonous hair” does smack of sensationalism, doesn’t it? It’s just the kind of thing I’d expect to read on the cover of some smarmy publication as I waited to check out at the grocery store.
But this was, in fact, a true account of a real species of rat that does kill its prey using poisonous hair. Better yet, I could read about it as if I was only interested in its scientific merits because there were no articles about Elvis sightings or ads for strange sexual enhancement products around it to suggest this might not be the case. The rat gains further tabloid credentials because, in addition to having killer hair, it’s also a giant rat as rats go—12-14” long—and has a crest or mane that would give a Chinese crested a run for his money. Kind of cute in a way, if it wasn’t for the hair. Hopefully no Chinese crested would decide to sample a chunk of crested rat back, though, because the poison in those hairs is capable of killing an animal bigger than an averaged sized dog, let alone one that small.
Crested rats get their poison by chewing on poisonous bark and then licking specially adapted hairs along their spines which are capable of absorbing and holding the toxin. Like other animals who borrow poisons from other sources, the goal isn’t to kill off all predators. The goal is to keep them from attacking at all. No matter how horrible the consequences of an anti-predatory display may be for the predator, it does the prey no good if they sustain debilitating injuries or die in the process. In order for such strategies to be worth the energy that goes into their creation and implementation, enough predators must survive an encounter to spread the word that it’s a bad idea to prey on the poison-carriers.
Another variation on this theme occurs in monarch butterflies who are much more common in my area than crested rats, thank goodness. Monarchs borrow their poison from various milkweed species which give them a taste their avian predators find distasteful. As with the crested rat, the success of the monarch’s strategy depends on enough predators having a negative encounter to warn others to stay away. But because of the monarch’s smaller size, shorter lifespan, and fragility, this may result in the death of some to save others.
But the story doesn’t end there for the monarchs. Another butterfly, the viceroy, appears very similar to the monarch, except for one critical difference: they’re not poisonous. But whereas the success of the monarch’s strategy depends on predators having a negative experience with one of them and then staying away from the rest, the viceroy’s success depends on predators sampling a monarch or two. If the predator munches on a viceroy first, it will keep doing so until it encounters a monarch. Only then will it be more likely to steer clear of both species. On the other hand, if the predator tries to eat a monarch first, the resulting taste aversion will protect the viceroys, too.
But even though this might seem like a good deal for the viceroy, it has its limitations. In order for them to succeed, their population must either remain smaller or appear later than the real deal. If they appear after their poisonous partners, their timing has to be perfect. Viceroys who delay too long may discover that predator’s memory of the distasteful encounter with a monarch has faded. Or a new generation of younger predators who never had a negative encounter with a monarch may have matured who would prey on them without fear.
Poison-borrowing and their mimicry are just two of the many strategies that make up the anti-predator repertoire, each and every one of them worthy of a sensational headline. But naturally, this got me thinking: Do we see corollaries of these behaviors in companion animals?
My initial response to this was no for two reasons. One is that the very nature of domestication prepares them for a life of dependency. It didn’t benefit domestic animals to possess specialized structures that could be used against humans. Those who demonstrated any move in this direction were most likely eliminated. As a result the domestic species repertoire of physical defenses is pretty much limited to teeth, nails, claws, or hooves, all structures animals used for other functions that carried more benefits than costs to humans. These included doing tasks such as keeping buildings and fields vermin-free, herding sheep or cattle over rough terrain, or pulling farm implements or carriages.
The second reason I suspect we don’t see specialized anti-predatory displays like those of the crested rat or monarch and viceroy butterflies in domestic animals is because these require generations to evolve. And this requires that those who most successfully deal with any life-threatening problems in a particular physical and mental environment survive long enough to pass that potential on their their young who then do likewise. Breeding animals with the greatest probability of success in the companion environment has not been a top priority in the United States for the last half century. Quite the contrary, the goal has been to prevent successful companion animals from reproducing at all.
As a result, increasingly Americans must select their animal companions from among those selected by other humans to survive in field or show ring, or those self-selected to survive on the streets, in the woods, or in other non-companion environments. Even if they do survive in a companion environment without these genetic advantages, the probability that they’ll be allowed to retain the reproductive capacity to pass that potential on to future generations is about nil.
The good news is that we probably don’t have to worry about dogs or cats with poisoned fur or other sophisticated anti-predatory skills cropping up in the pet population. The not-so-good news is that the fewer generations of solid breeding for the physical and mental soundness necessary to be successful animal companions, the less accurately we can predict how those animals will respond in our environments at all.
But in the meantime, who knows? Maybe sometime in the future a mimic of the crested rat will be discovered, too.
If you have any comments regarding subject matter, favorite links, or anything you’d like to see discussed on or added to this site, please let me know at mm@mmilani.com.