On a humid spring night last April, I went for a walk in Garber Park, a hillside forest on the eastern edge of Berkeley. In a stand of live oaks not far past the entrance my eyes happened to linger on a trailside log. And in a tiny hollow beneath the log’s base, reflected in my headlamp’s glow, were two gold-flecked black eyes and a dull pinkish snout.
I stopped for a closer look. The eyes belonged to a salamander: one Aneides lugubris, a species mostly native to the coastal oak woodlands of California and northern Mexico, more commonly known as an arboreal salamander. She—I didn’t actually know if the salamander was female, but preferred to guess rather than say it—took a step back on smoothly delicate legs but did not flee. I turned my headlamp to its red-light setting and sat beside the log to ponder: What is it like to be a salamander? To be this salamander?
It’s the sort of question I often find myself thinking about other animals. Some, however, are harder to answer for than others. Although we live in an era when the intelligence of animals—especially mammals and birds—is widely acknowledged, the minds of amphibians have received little attention.
They’re often considered primitive, as befits cold-blooded, mostly sedentary animals who retain many of the essential features of their ancestors, who first crawled onto land some 370 million years ago. Anatomical descriptions of amphibian brains tend to emphasize their simplicity. Relatively few studies of their cognition even exist. And at a gut-reaction, first-impression level, amphibians are simply—other.
To understand what it’s like to be any animal is an act of imagination; that goes extra for salamanders. Yet we can also draw upon a patchwork of life history, behavior, neurobiology, and cognitive science, full of holes and yet complete enough to suggest a picture.
“Can we ever completely know the perspective of another being? No. But that is also true of you and me: I will never fully inhabit your perspective. And that impossibility doesn’t mean it’s not worth trying,” advises Becca Franks, an animal behaviorist and environmental studies professor at New York University. “Quite the reverse: it would be offensive if I refused to take your perspective merely for a lack of ever being able to know it perfectly. The trying is what matters.”
To Franks it is a challenge with existential undercurrents. As a species with extraordinary power over the fate of nonhuman life, as curious creatures sharing a planet with multitudes, it is incumbent upon us to try to understand the perspectives of beings who happen not to be human. And so let us begin with an arboreal salamander.
As I sat down to consider the salamander, my headlamp’s red light illuminated her log. At the entrance to her burrow were fallen leaves and wispy vegetation; I imagined how extraordinary it would be to study them at eye-level scale, but they likely appeared to my salamander in low resolution. Salamander retinas have relatively few cells, and dramatically fewer of the nerves that carry signals between eye and brain. I may only have been a looming mass.
“Hello, little salamander friend,” I said, being the sort of person who greets the animals I meet. To her the words were likely a dull rumble. The auditory systems of salamanders are functional but simple, lacking an eardrum and the middle ear structures that would amplify and relay airborne sounds. Even so, vibrations travel from the ground through the bones of their forelimbs and into their inner ears. Earlier in the evening, the footfalls of joggers and neighborhood families out for a stroll, unaware of the amphibian just inches from their feet, perhaps registered as seismic.
My own ears pick up a steady crackling of tiny creatures moving through the fallen eucalyptus and bay and live oak leaves. I glimpse a few: a sow bug, an earthworm, springtails, all fare for an arboreal salamander. Should one pass close to her den, she may feel their movements—what must a millipede’s footfalls feel like!—see their form, and detect the motion with fly-catching precision. With a flick of her tongue she would snare the luckless creature before crushing it between muscular jaws lined with flattened, blade-like teeth.
Arboreal salamanders are sit-and-wait predators, using no more energy than is necessary. One can imagine how she apprehends her domain. “Salamander experience must be shaped by modalities we underappreciate: chemosensation, moisture gradients, and substrate vibrations,” Shannon Kundey, an experimental psychologist at Hood College who studies salamanders, tells me later. “Their world is likely less about vision and more about texture, humidity, and chemical trails.”
On a wet night, the salamander might leave her retreat and find another place to sit and wait: atop her log, perhaps, or even in a tree climbed with help from her prehensile tail. With a tap-tap-tap of snout1 to substrate, whatever detail is lacking from the salamander’s visual and auditory cosmos would be found in its odors: the leaves in varying states of decomposition, the scent trails of termites, the shelf fungus filigreed through her log, a constellation of odors to which I am as blind as she was to the stars.
And now, a philosophical digression: In imagining what that salamander perceived, we implicitly assume that she possessed some sort of consciousness, some sort of self, such that she subjectively experienced those sensations and even considered them, discriminating between the slight and the pronounced, the salient and the unimportant.
Some would say that this is not certain, that amphibians are not conscious at all, or that salamanders might be conscious but it remains inconclusive, or that salamanders are conscious but perhaps not aware of themselves as a distinct entity, or that they’re conscious and capable of thought but may not feel. Many philosophers and scientists have tied their intellectual selves into pretzels over this sort of thing. It all seems—please forgive the flippancy—silly to me, a lingering intellectual legacy of now-discredited, centuries-old conceptions of animals as akin to mechanical wind-up toys.
There is also an emerging school of thought which holds that to disentangle the sensations of one’s own movements from those of the external world is to be conscious, and that consciousness is inextricably intertwined with awareness and sentience, even in amphibians. They’re a package deal. There are gradations of these capacities, and the forms they took in the salamander beneath the log can be adjudicated later, but according to this argument, she had a sense of self. She was a someone.
The salamander’s chin moved up and down with her respiration, though she breathed not in the way we do but through her body’s semipermeable, capillary-latticed skin. Arboreal salamanders are members of the Plethodontidae family, characterized by an abundance of teeth and the absence of lungs; in a sense, their bodies are their lungs.
As well as oxygen, she absorbed moisture through her skin. Although salamanders’ ancestors evolved to live on land, they never fully left the water, and A. lugubris are among those who depend on wet surfaces and ambient condensation to keep from desiccating. Their skin must remain wet in order to exchange gases. If they become too dry, they cannot breathe.
What might that damp spring air—it had not rained for days, but coastal fog and the forest canopy kept the night humid—have felt like to the salamander? I think of the rejuvenating sensation of walking out of a cold hockey rink into a muggy spring night, multiplied by an evolutionary history that made such conditions critical to survival.
Whatever it feels like, suggests Anna Wilkinson, a cognitive scientist who studies reptiles and amphibians at the University of Lincoln in England, it at least feels good. For a mammal to be content, it needs to be sated and safe from predators—but an amphibian’s contentment, she thinks, depends on the comfort of their skin. Wilkinson describes trying to motivate fire salamanders to navigate mazes for experiments on memory: she offered them food, but the salamanders ignored it. When rewarded with several minutes’ stay in a damp box, they became enthusiastic navigators.
In saying that dampness feels good to a salamander, Wilkinson implicitly accepts that they can feel good—or bad—in the first place: that they have the fundament of emotion, a dimension of experience rarely acknowledged in amphibians.2 Some research has even suggested that amphibians are uniquely unemotional.
About a quarter-century ago, the physiologist Michel Cabanac found that frogs subjected to the ostensible stress of being handled did not respond with increased heart rates or body temperatures, as do lizards, birds, and mammals. These reactions are considered signs of emotional response, and Cabanac surmised that emotions arose after reptiles diverged from the amphibian lineage. His theory was further supported by the failure of toads and newts to show flavor aversion, in which an animal injected with an unpleasant chemical after eating a new food subsequently avoids the food. Cabanac’s amphibians kept eating. Had they been capable of discomfort, the argument went, they would have stopped.
To Wilkinson, Cabanac’s conclusions were premature and overly broad. They were based on only a few species. Later research documented emotional responses to the threat of predators, and aversion responses can be elicited by other illness-inducing chemicals. Salamanders also possess the necessary neurobiology to experience emotion. To me, the capacity to feel good or bad—and thus be rewarded with positive sensations for doing survival-promoting things, or dissuaded by negative sensations from doing what is harmful—is so evolutionarily beneficial that its presence should be a default likelihood. What better way to keep a salamander from drying out than to make moisture pleasurable?
Even more interesting than whether salamanders possess emotion is whether they have moods: whether, beyond momentary flushes of feeling good or bad, they might experience something akin to happiness or sadness. Wilkinson recently demonstrated this possibility for the first time in reptiles by adapting cognitive bias tests, which use responses to uncertainty—a strange object, a bowl that may or may not contain food—as proxies for emotional states. Wilkinson’s red-footed tortoises proved to have moods, and she thinks amphibians may be similarly capable. Rochelle Stiles, a biologist who oversees the care of frogs in a conservation breeding program at the San Francisco Zoo, goes further. She believes that making choices—where to go, what to do—is essential to the psychological well-being of amphibians. She even speaks of them as being fulfilled.
Yet all this doesn’t mean that the salamander beneath the log—who retreated another step but remained visible—experiences the same emotions we do. When humans are stressed, our adrenal glands produce extra cortisol, a hormone that increases blood sugar levels and heart rate, preparing us for action. In many other animals this is accomplished with corticosterone, a similar hormone. But when Sarah Woodley, a physiologist at Duquesne University, studied how lungless salamanders responded to seemingly stressful situations, she found that their corticosterone levels did not rise.
The observation echoed Cabanac’s findings, but Woodley interpreted it differently. She thinks the metabolic acceleration experienced by other vertebrates in response to stress would be maladaptive for salamanders, who, being lungless and prone to dehydration, are necessarily specialized for low-energy lifestyles. They may go for weeks or even months without food, and if their metabolism increases, so does the rate of evaporation from their bodies. Rather than speeding up, then, they shut down. They still become stressed, says Woodley, “but they experience it in a slightly different way.” The anxiety that accompanies our own stress response is missing from arboreal salamanders—but that doesn’t mean they feel nothing. Stress still has a fundamentally negative valence for them. We just don’t know what it feels like.
For many of California’s salamanders, breeding occurs on rainy nights when they find their way to ponds and slow-moving streams where they mate. Arboreal salamanders follow a different life history, instead staying on home ranges of up to an acre in size and finding partners by their scent.
Having found one another, they engage in hours-long courtship rituals—foreplay is another term—with pairs performing a complex sequence of steps and contortions astride and against one another’s bodies. Arboreal salamander courtship was once thought to be a male-dominated affair, but research by Nancy Staub, a biologist at Gonzaga University, suggests that females are active participants as well. Each partner rubs glands against the other, with males even abrading their partners’ skin so that pheromones flow directly into their bloodstream. The chemicals facilitate courtship but the precise mechanisms are unknown, says Staub. They don’t simply trigger a behavioral response but seem to exert subtler influences. It seems safe to say that it all feels good.
If successful, the ritual climaxes with the male depositing a sperm-filled globule in front of the female, who may—if she is sufficiently pleasured? excited? compelled?—position herself above the spermatophore and pull it into her cloaca. The sperm will fertilize her eggs, which are laid on a burrow’s floor or suspended from its ceiling. For several months the mother guards them attentively, even wrapping her body around the eggs to keep them from drying. The moisture that is so precious to a salamander, that motivates them even more than food, is given to those orbs of developing life.
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What does a mother arboreal salamander feel for her eggs? What do they mean to her? Egg-guarding is a form of parental care, which is so well-described among amphibians that review papers have been written on the phenomenon. In them no mention is made of the subjective experience, of whether the act of care is accompanied by feelings of care.
“We so often sit in that tension between what has been rigorously documented and what seems likely,” says Shannon Kundey. “Being overly cautious can inadvertently reinforce the idea of absence, when in fact we just haven’t looked closely enough or asked the question in the best way for the species.” That a salamander mother not only performs but feels care is uncertain but quite possible. To me it seems the likeliest explanation.
After her eggs hatch the young salamanders are presumed to remain at home. The social habits of Aneides lugubris are not well-documented—courtship notwithstanding—and to a lesser extent conflicts; their bodies often bear the crescent-shaped scars of toothy battles with kin. And yet a 1903 paper describes dens containing young salamanders and their mother, and perhaps even both parents. During dry spells salamanders may congregate in burrows and damp tree hollows.
What social dynamics govern those gatherings or occur on the landscape is unknown, but brain regions involved in social decision-making are present in salamanders, and research suggests that scent is central to individual recognition. That is yet another mystery: What would it be like to know one another not by sight, but by scent?
Most everything described so far requires little capacity on the salamander’s part to engage in reflection. The salamander beneath the log could have been living in an eternal present, a conduit of sensation and response, reacting reflexively to stimuli with no memories of the past or idea of the future. Such an existence is conceivable. It would be as marvelous in its own way as any other.
But is it likely? In Kundey’s experiments, she described how tiger salamanders reacted when unfamiliar objects were added to their enclosures or familiar objects were moved about: they noticed. That might not sound like much, but it is profound. The ability to recognize novelty “suggests salamanders are not locked into purely reflexive responding but instead track their environment,” she says. “It implies a continuity of experience over time—a kind of subjectivity that goes beyond pure immediacy.”
The auditory systems of salamanders are functional but simple. Catalina Luna
What else did my salamander’s mind register? Repeated migration is regularly observed in many amphibian species, and though arboreal salamanders don’t range as widely as certain others—California newts, for example, may travel two miles between homes and breeding waters—even a backyard-size territory is vast to a creature no longer than my hand. At a minimum she likely knew her territorial routes and its most important features. Up the path was a spring—just a trickle of water, really, running through a mossy grotto, but to a salamander it could be manna. Perhaps she remembered salamanders she had met, the qualities of her log’s fungi, the habits of her prey, the details of her world.
One can only speculate, but all that information is at least relevant to survival. Natural selection may have favored its retention. Which doesn’t mean a salamander reflects upon its past; the notion strikes Wilkinson as unlikely, though she added that if salamanders indeed do this, it would be difficult for us to know.
Wilkinson and Kundey also tested their salamanders’ memories upon emergence from brumation, a long-term dormancy that many amphibians enter when temperatures fall. (Arboreal salamanders estivate, lowering their temperature and metabolism when it’s hot and dry.) Brumation is akin to hibernation, which in mammals can degrade memory, but the salamanders recalled previously learned navigation tasks. At least some of their mental world remained intact. Other memories may have been lost, though, and Kundey also found that especially cold temperatures upon their waking made the salamanders more forgetful.
It’s fascinating to imagine this cyclical life, punctuated by long spells of deep inactivity from which one emerges with some memories retained and others lost. Perhaps only the most important remain and salamanders are fated to learn their worlds anew, again and again. Will we ever truly know whether this is true, or what this is like? Probably not—but uncertainty is an invitation.
What does it feel like to regenerate a limb, as salamanders do? What does a pill bug taste like? Do arboreal salamanders play? How do they know, without having ever performed them, the steps of their courtship dances? How do they know, when leaping from a treetop to escape a hungry owl or a snake, to spread their arms wide, using tail and torso to steer their fall? Do they feel a yearning to climb? Have friends? What does a salamander find aesthetically appealing? And what does an arboreal salamander learn over the course of a decade-long life? Long-term studies in frogs show that after a certain age, their survival rates become extremely high; can an elderly amphibian be wise?
To even consider these possibilities, however wrong or speculative our answers might be, is to acknowledge life’s richness. It is an exercise in humility, a recognition that the limits of human knowledge are not the limits of reality. It is an act of kinship.
After a while I tried to take a video of the salamander. As I did, I heard a crackling in the understory and sat up with a start. A pair of eyes reflected my headlamp back at me. The animal ran off with a huff. Chastened, I turned my light off and sat for a while in darkness. When I turned it back on, the salamander was gone.
Endnotes
1 Salamanders have a secondary olfactory system centered on the vomeronasal organ, which resides in their nasal cavities. Arboreal salamanders and others of their family also have grooves in their upper lips; when they tap their snouts to the ground, capillary action pulls water up through the grooves and into their vomeronasal organs, which detect the chemicals it carries. Back to story
2 Emotions can be tricky to define, not least because we often think of physical and mental experiences as separate. But imagine being pinched: while the sensation of pressure can be purely mechanical, the feeling of pain is emotional. It is produced and interpreted in the brain—not as complex as something like heartbreak, but still a mental experience. Back to story
