Reconnect With Nature Blog

Beetle Defensive Secretions

Chris Wemmer, a distinguished mammalogist and conservation biologist, suggests that it might be interesting to taste an Eleodes beetle (see comment). I don’t think that this would be a good experience. Some years ago, I was doing a study of biodiversity on one of the islands in the Gulf of California. As part of the study, I was trying to count the number and species of Tenebrionid beetles on the island. Because desert animals switch to being nocturnal during the heat of the summer, the beetles were active only at night. I set up a 200 meter transect, and walked along this transect every 30 minutes, counting the number of beetles that I saw and identifying each species. Since it was quite dark at night, I set up the transect between two large Cardon cacti (Pachycereus pringlei) that served as landmarks for me to steer by.

Around midnight I stopped to pick up an Eleodes beetle that I could not identify to species. I inspected the beetle in my flashlight beam, then set it down and watched it scuttle away. During the time I was holding it, the beetle must have sprayed my fingers. I could smell the pungent, almost sweet smell of defensive secretions, but I thought that the beetle had gotten the secretions on its own body, and not on me.

It was a hot July night, and sweat was pouring down my face. Without thinking, I brushed my fingers across my moustache, wiping off the sweat. Suddenly it felt like a sledge hammer hit my sinuses. It was like eating a huge dollop of Japanese wasabi (Eutrema wasabi), the green horse radish-like herb that comes with sushi, but much worse. My eyes started tearing, and liquid was flowing copiously out of my nostrils. I could barely breathe.

After a few minutes, my sinuses settled down, but the worst was still to come. As I tried to walk the transect, I found that I could not steer in a straight line. I could see the Cardon at one end of the transect, and I tried to walk toward it, but I kept drifting off to either the right or the left from the straight line, without being able to control where I was walking. I tried for about half an hour, and finally gave up, sitting down in the dirt with my head in my hands.  Two hours later the effect seemed to go away, and I was able to get back to my camp and roll into my sleeping bag. The next morning I was fine.

Having smelled the defensive secretions of a number of different species of Tenebrionids, I can say that not all secretions have that effect. Some merely cause a watering of the eyes and a tanning response in which the skin that has been sprayed turns brown.  But some defensive secretions are apparently quite potent. I try to imagine what it would have been like to taste the secretions of that beetle. Somehow, my imagination fails me.

Watching Snake Behavior

Doug Von Gausig (see previous post and comment), who is an accomplished photographer and nature recordist, sent me a video of a patch-nosed snake (Salvadora hexalepsis) excavating a burrow (watch the video).  In this video, you can see some fascinating behavior.  The snake goes into the burrow, apparently loops its body around some sandy soil, emerges holding on to the soil with a coil of its body, and releases the soil away from the burrow.  This is an elegant solution to excavation. I have often wondered how snakes manage to dig burrows without having hands. Now I know.

As I was watching the video, I was reminded of watching Sphecid wasps (genus Ammophila) excavating burrows. A wasp would go into the burrow, apparently use its legs to scrape up some dirt, put the dirt between the coxae of her hind legs, back out of the burrow, fly up into the air for about one meter, and release the dirt, which blew away in the wind as a fine plume. The wasp would do this over and over, making sure that no dirt was piled up at the entrance to the burrow as a tell-tale sign of activity for predators and parasites to notice.

I tried to photograph this activity. I found a wasp that was just starting to dig her nest and set up my camera. After a few of her forays in dropping the dirt, I realized that I had a better camera angle if I moved around to the other side of the burrow. I set up the camera again and waited for the wasp to emerge. She did, and instead of flying back, she flew around on the other side of me and started searching for her burrow. At first I was puzzled, but then I remembered the classic Tinbergen experiments with wasps and pine cones. She was using me as a landmark to find her burrow, and did not realize that the landmark had moved. So she was completely disoriented. Needless to say, I moved back to my original position, and she promptly found her burrow.

But back to the patch-nosed snake. I found it very interested that after emerging, the snake spent some time looking around, apparently watching for potential predators. Digging burrows must be a dangerous activity for snakes. A predatory bird or mammal could sneak up on the snake when its head was inside the burrow and grab it before it had a chance to react.

Watching animals like this is an excellent way of reconnecting with nature. Not only do you get a sense of what their behavior is like, but you also can get a sense of what might be important in their lives. And then you can ask yourself the question, are similar problems important to your life?

Mimicry in Beetles

Doug Von Gausig (see comment) asks an interesting question about Tenebrionids. He asks whether there are any Carabid beetles that do a head-stand display like the Tenebrionids, or if it is only the Tenebrionds that do this.

The situation among these beetles is complex. There are a number of Tenebrionid beetles (many in the genus Eleodes) that do the headstand display and have defensive sections. Many of these species look very similar to one another, in an apparent display of Mullerian mimicry, where all of the species converge on a similar phenotype so that predators can learn a general color and body type and know that everything that looks like that is either toxic or distasteful. Some of these beetles have smooth elytra (the wing coverings, which in the case of these beetles are fused together because the beetles are incapable of flying), while others have grooves on the elytra.

These beetles need an ample supply of moisture (that they get from eating moist vegetation or drinking dew) to manufacture the defensive secretions. When they do not get the moisture that they need, they do not do the headstand display, but attempt to run away from a potential predator.

There are other Tenebrionid beetles that will also do a headstand display, but lack any capability of producing defensive sections. These are beetles in such genera as Gonasida and Stenomorpha. They look just like the beetles with defensive secretions, have the same behavior, and are found in the same places. As such, they are Batesian mimics. Batesian mimicry is where there is a model that is dangerous or distasteful, and a mimic that is edible but looks and acts like the model.  Some of these species have grooved elytra while others have smooth ones, just like the species of beetle with defensive sections that they are mimicking.

Then there are Cerambycid beetles, or long-horn beetles, in the genus Moneilema that mimic the Tenebrionid beetles with defensive secretions.  These beetles are shiny-black, with smooth elytra, and do a headstand just like the Eleodes, but lack any defensive secretions. Unlike many long-horn beetles (who are called that because most members of that family have long antennae), these beetles have short antennae. However, their antennae are still longer than the Tenebrionids, who have really short filamentous antennae. So the Moneliema have an interesting adaptation. They have a groove running along the length of their body into which they can insert their longer antennae, making the antennae seem to disappear. One potential hitch about doing this is that there is a gray area along their body where the thorax is connected to the abdomen, and a black antenna would be visible against this gray background. To counteract this, the Moneilema have a gray segment in an otherwise black antenna, and this gray segment exactly matches the color and position of the gray area between the thorax and the abdomen. When the Moneilema do their headstand, they look just like the Tenebrionids with defensive secretions.

Finally, there are the Carabid beetles. Some of these beetles are also black, and are roughly the same size and shape as the Eleodes. For example, the beetle Scaphinotus petersi looks superficially like some of the Eleodes, but runs quite fast and low along the ground, instead of walking relatively slowly like the large Tenebrionids described above. I am not aware of any of the Carabid beetles doing a headstand display. although many Carabids have defensive secretions. They seem to rely on speed to get away from their predators. Some Carabids such as the bombardier beetles (Brachinus) have defensive secretions that mix in an internal chamber and literally explode out of the rear of the beetles in a hot burst (100 degrees Centigrade) of fluids.

An interesting question is how this mimicry might have evolved.  For a predator to learn that a beetle is distasteful, the predator has to first taste the beetle, something that often proves to be fatal to the beetle. We have to assume that a small mutation that makes a non-toxic beetle look slightly more like a toxic one is enough to lower predation pressure on that beetle, and over millions of years the mutations that result in closer convergence are those that survive in the gene pool through natural selection. Personally, I have to marvel at how good that convergence can be in this beetle mimicry system and in other insects with Batesian and Mullerian mimicry.

Watching Beetles

I was walking my dog around our local pond when I noticed two people, a man and a woman, peering down at something on the path. I stopped well behind them to give them space. At the same time, I tried to see what it was that they were observing. At first, I could not see anything. Then, suddenly, I noticed a black dot moving on the path. Now I knew what had captivated their attention.

They were looking at a Tenebrionid darkling beetle (Eleodes longicollis, family Tenebrionidae). This beetle is black, completely flightless, and about 26 mm long (a little longer than one inch).  As they would get close to the beetle, it would do a headstand, lifting its butt up into the air and standing very still. After a while, sensing no movement, the beetle would lower its butt down and start to move along the path, Fascinated, the people would move closer, casting their shadows on the beetle, which would stop and raise its butt up again. Clearly, the people were engrossed in watching this behavior.

I thought of coming up to them and telling them a few facts about these beetles.

I wanted to tell them that these beetles have defensive secretions, made up of quinones and hydrocarbons, that they squirt out of glands near their anus at predators who try to eat them. This is a great defense against predatory birds and small mammals. However, it doesn’t work against the carnivorous Grasshopper Mouse (Onychomys leucogaster). Experienced mice come up to a beetle that is doing a headstand defensive display, grab the beetle with their front paws, turn the beetle around, and stick the beetle’s butt into the sand. With the beetle’s defenses immobilized, the mouse chews off the beetle’s head, and then proceeds to eat at leisure down to the level of the defensive glands. Some mice go on killing sprees. Sometimes you can find a row of 10 or more beetles stuck with their butts into the sand, positioned like telephone poles, all with their heads chewed off but otherwise uneaten.

The defense doesn’t work against Striped Skunks (Mephitis mephitis) either. When a skunk comes across a beetle doing its headstand display, the skunk first sniffs the butt end of the beetle. If the skunk detects the odor of defensive secretions, he then starts to roll the beetle around in the sand with his front paws. Meanwhile, the beetle is releasing its defensive secretions. Periodically, the skunk will stop the rolling and take a small taste of the beetle. If there are still defensive secretions present, the skunk will shake his head vigorously several times and then continue rolling. Once the beetle has exhausted its supply of secretions, the skunk proceeds to eat it.

However, the beetle’s secretions work well against Harvester Ants (Pogonomyrmex rugosus). The ants have a disk-shaped area around their nest opening, onto which foraging workers drop seeds and bits of vegetation that they pick up anywhere within about 100 meters (300 feet) of the colony. Other workers emerge from the nest, pick up these seeds and droppings, and take them down inside.  The Tenebrionid beetles come into these disk-shaped areas and feed on the seeds and vegetation that the ants have brought. If the ants try to sting or otherwise attack them, the beetles spray minute quantities of defensive secretions, with great accuracy, at the approaching ants, causing them to immediately stop, curl up into a C-shape, and start cleaning themselves. On days when the ants are particularly aggressive, you can see a beetle leisurely feeding while perhaps 10 or more ants are frantically cleaning themselves nearby.

I wanted to tell these people all of that. But I didn’t. Instead, I waited until the beetle left the path completely and was lost in the surrounding vegetation, and then I walked past them, merely saying Hello.

Sometimes, there is a place for lots of information. Other times, there is a place for simply watching and appreciating what nature has to offer.

Saving Prairie Dogs

Moving the rattlesnake (see previous post) brought to mind the issue of transplanting prairie dogs. There are 5 species of prairie dogs in North America. Of these, one is considered threatened under the Federal Endangered Species Act, another is considered endangered, and environmental groups are petitioning the U. S. Fish and Wildlife Service to list the remaining three species as either threatened or endangered.

Once upon a time, there were about 5 billion prairie dogs in the grasslands of the American West. These small groundsquirrels form the backbone of the western prairie ecosystem. By digging burrows and clipping vegetation, prairie dogs change the landscape of grasslands, providing homes for a variety of other vertebrate and invertebrate species. Some 200 species of vertebrates either depend on prairie dogs or are associated with prairie dog colonies. Many species of insects and invertebrates use the prairie dog burrows for shelter.  The social structure of prairie dogs is complex, with animals occupying territories that they defend against other prairie dogs in nearby territories. They have a sophisticated system of alarm calls to predators that borders on being a language.  In many respects, they are similar to people: They live in colonies called towns, they have a rich social and family life, they spend a considerable amount of time kissing each other to reaffirm social bonds, and they communicate a complex amount of information about the world around them. Along with the bison, the prairie dog is one of the icons of the American West.

In many states, prairie dogs are considered pests and vermin, and are regularly poisoned and shot.  Today, we have perhaps 1-2 percent of their original numbers left. Because prairie dogs eat grass, they are commonly thought to compete with cattle for forage. Never mind that in historical times prairie dogs nicely coexisted with bison, whose diet is similar to that of cows. Their burrows are thought to regularly break the legs of cattle and horses, although finding someone whose horse or cow actually broke a leg in a prairie dog burrow can be difficult. And they are susceptible to bubonic plague, a disease that people introduced into animal populations in the American West in the early 1900s. Plague kills almost 100 percent of the prairie dog colony that succumbs to it, and is a major source of mortality for these animals, along with poisoning and shooting.

Throughout the American West, prairie dog colonies are being destroyed by development. Their towns are often in flat places that are perfect for the construction of subdivisions. Along the Front Range of Colorado, there were once grassy valleys with many prairie dog colonies between Denver and Boulder. Now there are subdivisions popping up all over, so that soon Denver and Boulder will be contiguous, with only signs telling the casual visitor that he or she has left one city and has entered another.  As other cities throughout the range of the prairie dogs expand, the colonies either wink out of existence or become urban islands surrounded by a sea of houses.

A few citizen groups are trying to save prairie dogs by transplanting them to more isolated sites, away from urban areas.  This is backbreaking and often heartbreaking work. The number of sites where prairie dogs can be transplanted is very limited.  In a state like Colorado, prairie dogs cannot be transported across county lines without the express permission of the county commissioners. In other states, landowners can be fined huge amounts of money if prairie dogs migrate from their land into the land of their neighbors. When transplant sites can be found, moving the prairie dogs involves countless hours of work, trapping the animals, digging new burrows, moving everyone, and providing food at the new site until the prairie dogs become adjusted to their new surroundings.

While transplanting offers an immediate solution to saving animals who would otherwise be killed, we need a long-term solution to the rampant destruction of our environment and our wildlife. As our human population expands, so do the cities and suburbs. This is affecting our grasslands. Currently, there are 55 grassland species that are listed as threatened or endangered under the Federal Endangered Species Act and more than 728 species are candidates for listing. The consequences of human expansion are world-wide. Prairie dogs are among the almost 20% of all mammal species on earth today that are currently under threat of extinction. Estimates have suggested that we lose about 4 species of plants and animals per hour, or about 100 species per day, or 36,500 per year, primarily in the tropical forests.  Human beings are responsible for the biggest number of extinctions since the dinosaurs died out some 65 million years ago.

The expansion of human population currently seems to have little room in it for the prairie dogs. Yet, ironically, as prairie dog colonies and natural grasslands are destroyed in the name of development, the reason that many people move into newly-minted subdivisions is to escape the crowding and lack of nature found in inner cities. People enjoy the very same natural surroundings that developments often obliterate.  Small parks in the middle of subdivisions are sometimes poor substitutes for nature.  After a subdivision levels the surrounding landscape, the first thing that most residents do is plant trees, bushes, and grass, and set up bird feeders and ponds to attract some of the wild animals that inhabited the place. Some developers capitalize on this and build subdivisions that have a non-intrusive footprint set into the natural landscape.

And here is one key to saving prairie dogs.  From a pragmatic economic standpoint, developments set in natural surroundings often command higher prices than developments that are in barren, sterile and featureless landscapes.  If prairie dogs can be seen as an economic attraction, they might have a chance to survive the tide of urbanization.  Prairie dog colonies are fun places to watch animals. They are one of the few mammals who are active in the daytime. Unlike prairie dogs, most North American mammals only come out at night. And a prairie dog colony is a constant hum of activity. Animals chase one another.  Pups kiss each other, and kiss their moms.  Dads and moms stand at alert, watching for predators.  Something is always going on in a prairie dog colony. In fact, zoos have found that prairie dogs are often their most popular exhibits.

Rather than destroying prairie dog colonies, cities, suburbs, and exurbs can develop watchable wildlife sites, where people can go to view the prairie dogs.  This can give people a sense that they can reconnect with nature, and can provide an outing for both adults and children. It can also be a source of tourist dollars, where tourists can come to watch the prairie dogs and stay to eat at local restaurants and spend the night at local hotels. And developers can charge higher prices for homes around such watchable wildlife sites, much the same way that houses near golf courses command higher prices.  Golf course houses create the illusion that the house is set amid a sea of green and abundant nature. Watchable wildlife sites can create the same illusion.

Also, before it is too late, we need to establish large reserves where animals such as prairie dogs and all the attendant plants and animals can live in safety.  Following up on the economic theme, developers can be encouraged to build hotels and concessions at the periphery of these reserves, and tour companies can take ecotourists through the reserves on nature rides, much the same way that tourists now view large animals in Africa. Although many people have the prevailing view that we have plenty of open space, we have merely to look at the growth of the human population in states like California to see that open space is rapidly dwindling. At our current growth rate, the time is rapidly approaching when we will no longer have much open space available for wildlife.

Finally, we need to continue to use legal and educational means to persuade public agencies to conserve the animals that they are charged with protecting.  There are a number of citizen and environmental groups who are working very hard to ensure the enforcement of the Endangered Species Act and the dissemination of educational materials about the importance of prairie dogs and grassland ecosystems. Many of these groups operate through donations from like-minded supporters.

While in theory just knowing that we are saving a piece of our heritage should be sufficient in itself, in practice it is economics that will determine how much of our heritage of plants and animals will remain for posterity.

Moving A Rattlesnake

For some time, a female Western Diamondback Rattlesnake (Crotalus atrox) has been hanging around our house. She spent the winter sound asleep under our porch, and now that the weather has turned warmer, she has been emerging to enjoy the daytime temperatures. Her favorite has been to curl up underneath a low rabbitbrush (Chrysothamnus nauseosus) right next to the porch, and either snooze or delicately watch the passing scene.  Sometimes a distant rabbit would catch her eye, or an Ash-Throated Flycatcher (Myiarchus cinerascens) nesting nearby would hover over her, and she would lazily turn her head from one side to another, before curling up again in a new posture of repose.

Our problem was that she was curled up near our back door, near one of the main paths into and out of the house. We changed our behavior to accommodate her.   Most of the time, we would go out of the front door and swing around the other door, giving her a wide berth. Sometimes we would look out the window at the back porch to see if she was out. But her camouflage is so wonderful that she disappears into the background and is extremely difficult to see, even when the distance from the window to her is less than 2 meters (6 feet). Looking for her is like looking at one of the optical illusions found in books on vision. You look and see nothing, and then you look again and suddenly she pops into view where seconds ago you could have sworn that there was just bare dirt.

We tried to be respectful of her right to be there. However, we were faced with a dilemma. First, as a female, she was probably pregnant, and would soon have 4-5 babies, young rattlesnakes whose venom is just as potent as an adult’s, and who do not know yet when to bite and when not to bite. Second, as the days and nights heat up, she will become more active, and the probability of stepping on her somewhere around the house at night will become much greater.

She is a good-natured snake, and probably would not bite us when we walk near her. Last year, we must have walked past her many times, sometimes centimeters from her nose, without realizing that she was there. Even now, she lets us walk to within a half-meter or less without any concern. Before I realized that she was planning to be a permanent fixture of the back porch scene, I walked out the back door, my mind engrossed in a problem, and only peripherally noticed that there was a one-meter snake lying across the porch. I stopped perhaps 15 cm (6 in) from her head. Her response was to lazily flick her rattles twice, as if to say, hey stupid, watch where you’re going!

But accidentally stepping on her at night is a real concern. And while she is good natured, we have no illusions that she might not bite if someone inadvertently hurt her. Responding defensively to sudden pain seems to be a basic animal instinct. Even the most loving dogs will bite their people when hurt and in pain, not out of malice, but out of an instinct to defend themselves.

We talked about what to do. On the one hand, this is her home, and we did not want to deprive her of her land and burrow. On the other hand, there was the issue of safety, both for us and for her. We had gotten quite fond of her.  Could we reach a compromise that would be good for her and good for us?

Finally, we decided that moving the snake would be best for all concerned. I contacted a friend who is an expert on rattlesnake behavior. She agreed to come and help with the move, bringing her tongs, padded so as not to hurt a snake and attached to a 2 meter (6 ft) pole.  The tongs deftly uncurled the snake from the rabbitbrush.  My friend pointed out to me that it is very easy to damage the snake’s spine, so we needed to be careful not to drop her, and we needed to pick her up so that the head end and one-third of the body was on one side of the tongs and the tail end and two-thirds of the body was on the other side.  She had 10 rattles on her tail. My friend said that these snakes molt twice a year, adding a rattle each time they molt, so the snake was probably 5 years old. We placed her into a bucket, and the lid was closed.

Then there was the problem of where to take her. My friend told me that studies have shown that rattlesnakes displaced even one kilometer (0.6 mi) away from their home range have a much greater chance of dying, probably because they are placed into unfamiliar terrain and are more easily found by predators, or become dehydrated from lack of cover.

We decided to move the snake away from the house, some 100 meters (300 feet), into an area of rocks and bushes. The rocks had lots of crevices, and there were abundant holes underneath them where a snake could slither and hide from the sun.  Nearby were woodrat nests, suggesting the potential for an abundant food supply.  The snake could come out from under the rocks and bask in the bushes, while still having plenty of cover to protect her from predators.  It seemed to us a perfect place for her to have her babies.

My friend lifted the snake out of the bucket and placed her on the ground. The snake slithered quickly under a large rock, rattling at us to show her displeasure with being handled.

Now we are hoping that she stays there. We have covered up the knot holes that she was using to get under the porch. For us and for her, the new place seems like a good solution. But will she cooperate? Time will tell.

Animals And The Relativity Of Time

Yesterday, as I went to check my hummingbird feeder, a male Anna’s hummingbird went zooming past my face and stopped a few centimeters from my nose, hovering and looking at me. Then, apparently reassured that I was not going to tamper with his food supply, he zoomed off to a nearby tree to sit and watch for intruding males that he could chase off with vigorous displays of speed.

I thought about how fast he can fly.  His reaction time to obstacles in his environment is so much faster than mine.  He can fly several rings around me before I can even lift my arm to my face, and he can change course before I can even comprehend where he is going. Apparently the processing time for incoming stimuli is faster in his brain than it is in mine.  His physiological processes are much faster than mine as well. His heart beats around 600-1000 times per minute, while mine beats around 60 times per minute.

This led to me wondering if time is the same for all animals.  We humans have an average lifespan of around 70 years.  A dog’s lifespan is around 10 years. A hummingbird lives for perhaps 6 years. And adult honeybees live for 30 days. Do they all perceive time the same way that we do? Is a day for us the same as a day for a hummingbird, or for a honeybee?

Soon I will have to drop off my dog at a kennel, so that I can leave for a weekend speaking engagement. My dog will be there for only three days. But is his perception of time the same as mine? If a dog lives 10 years, then each of our years is the equivalent of 7 dog years, and each of our days is the equivalent of 7 dog days. Does that mean that it will seem like three weeks in the kennel for him, rather than three days?

And speaking of perception, I remember having one of the old-time vinyl records of animal sounds, where a whale song was sped up 20 times and sounded like a bird song, and a bird song was slowed down 20 times and sounded like a whale. Does that mean that birds can process sounds faster than whales? I know of course that low frequency sounds (such as those found in whale songs) propagate farther than the higher-frequency sounds found in bird songs, and this is an advantage for animals that communicate over long distances. But is that the whole story? Maybe whales live longer and perceive time as being slower than shorter-lived birds.

Einstein showed that time was relative to the speed that one travels. Maybe the perception of time is relative to one’s lifespan, the speed at which we live.  For the Anna’s hummingbird, perhaps I am moving in extreme slow-motion, somewhere between dead-stop and barely-mobile.

Are We Unique?

     I recently read an editorial in the 03 March 2007 New Scientist that had the title, “We're not unique, just at one end of the spectrum.” The editorial pointed out that humans were long thought to be unique in their skills and accomplishments. Now, however, a variety of animals has been shown to use tools, to have some if not all of the elements of language, and to have cultural transmission of information. The editorial concludes that we are not unique, and this lack of uniqueness should give us more connectedness with all of life.

     I applaud the editorial. I think that this is an excellent re-orientation to our thinking. In the 1970s, humans were considered to be unique because we of all animals could make tools. Then along came Jane Goodall’s studies of chimps who could fashion tools that could be used to scoop termites out of their mounds. Suddenly there was a plethora of examples of animals using tools, including examples now of chimps using spears to hunt gazelles.

     Then in the 1980s, human were considered unique because we had culture, defined as information transmitted by learning from one generation to the next. But John Tyler Bonner’s book, The Evolution of Culture in Animals, showed that a number of animals could transmit information as well to other generations. The uniqueness of culture fell by the wayside.

     In the 1990s, language was considered to be just about the last bastion that separated us from the rest of the animal world. But then a variety of studies started to show that animals also had language. Vervet monkeys, Diana monkeys, and Campbell’s monkeys had different words for different predators. And lest you think that only primates were capable of this, studies have shown that prairie dogs have most of the design features found in human languages, and chickens have different calls for aerial and terrestrial predators.

     But I would like to add a word of caution about the interpretation that we humans are at one end of the spectrum. That smacks of the Aristotelian Scala Naturae or the Great Chain of Being, in which all animals were ranked in a linear chain, with humans (of course) at the top and the amoebas at the bottom. The Scala Naturae provided the justification for assuming that monkeys were incomplete copies of humans, and cats, dogs, rodents, and pigeons could be used to find out how humans learn and react physiologically. Yes, we all are related evolutionarily, and we all have certain evolutionary commonalities. But we each have our own species-specific differences, and if we humans were not writing with our anthropocentric perspective, it might be difficult to know where the end of the spectrum might lie.

     In fact, I argue that there is no end to the spectrum. We humans do some things extraordinarily well. But there are other things that we can’t do. We can’t hear in the ultrasonic range, the way that bats and dolphins can, and we cannot use ultrasonic information to form “mental pictures” of the objects that are out there in complete darkness. We can’t generate electricity the way that electric eels can, nor can we hear subsonic sounds the way that elephants can. We can’t even spread our wings and fly the way that a dragonfly can.

     Nature is a collection of unique species. Certainly, there are evolutionary connections, but there are specialized adaptations as well, that make every single animal and plant species unique. And where we draw the end of the spectrum depends on our point of view. Perhaps a better interpretation might be a cloud of points, like stars in our universe, with some points closer to others depending on their evolutionary connections, and no end to the spectrum, just like there is no end to the universe.

All Life Is Special

A few days ago, a story on NPR said that college students were more narcissistic and self-centered than they were in the past.  A recent study (see link) found that students’ scores have consistently risen on the Narcissistic Personality Inventory test since 1982. The study suggested that this might be due to teaching children that they are special, and further suggested that children who think that they are special will have less empathy for others. 

Not having seen the actual study, I cannot comment on the details. However, it seems to me that having children think that they are special should not be a problem.  After all, every human being on this earth is special, in that no one has exactly the same genetic makeup. Each individual is unique, and in that sense is special. No one has exactly the same talents, beliefs, motivations, and appearance as any other human (identical twins perhaps come closest to this).

However, forgetting that each individual is unique, we often make broad generalizations about people and their behavior. At the extreme of this is the categorization of people into stereotyped groups or populations.

This kind of thinking carries over to the way that some people view animals. Some wildlife managers and other biologists think of animals not as individuals, but as populations.  I have had biologists tell me that individual animals do not matter, that it is the population that matters, so there is no point in trying to save or rescue single animals.  On this basis, some people feel free to “cull” animals to preserve the population, or to exterminate groups of animals as long as the populations are not seriously affected.

But whether they live or die matters to individual animals. Just as all humans are unique, so is every animal.  And all life wants to live.

People thinking of themselves as being special might be a good trend. Rather than having less empathy, perhaps children who are raised feeling special about themselves might have more empathy for others who are also special. If they think of themselves as special, perhaps they will realize that all living things on this Earth are also special, and deserve to live.

A Winter Butterfly

Yesterday I went to one of my favorite places, a spring-fed stream.  The stream pops up out of the ground from springs and rushes headlong down a gentle slope for perhaps 6 miles (10 km) before it plunges back underground, not to be seen again.

During its journey, the stream gurgles through a canyon that is about 300 feet (100 m) across, with fairly steep walls rising up some 60 feet (20 m) on either side. The stream itself is only about 3 feet (1 m) wide. Along the sides grow large sycamore trees, small willows, and a variety of other riparian vegetation. Outside this narrow canyon is high-desert: cacti, mesquites, crown-of-thorn trees, vegetation that seldom tastes a drop of the water rushing by so near.

Now it is winter, and few animals are about. In summer, the stream is a magnet for desert life seeking water. Flycatchers sit in the branches of the sycamores and swoop down to catch the insects flying in swarms. Desert darkling beetles (Eleodes, in the family Tenebrionidae) wander around the banks, having drunk their fill of the water that they use to stoke the fluids in their defensive glands. Skunks come in at night to eat the darkling beetles, rolling them around in the sand until the defensive secretions are completely depleted and then holding the beetles in their front paws and munching on them as if they were hotdogs at some family picnic. An occasional mountain lion or bobcat comes by to drink furtively. Dragonflies patrol their territories with flashes of metallic blue and glimpses of scarlet, and damselflies daintily flitter from one reed to another, watching for intruders.

In the cold of winter, most of the insects, birds, and mammals are gone. The sycamores stand naked, stripped of their leaves, with only jutting branches reaching up toward the sky.  The lush green grasses found in the summer are dead, yellowed and broken by the wind and an occasional passing deer.

I sat on a rock by the edge of the stream, listening to the water whispering the sounds of half-caught words that echoed from the canyon walls. Suddenly a movement caught my eye. Near me was a butterfly, a Mourning Cloak (Nymphalus antiopa, in the family Nymphalidae), flying up from the ground, its black wings bordered with brilliant yellow gleaming in the sunlight. The butterfly flew over my head several times and then settled back on the ground. I moved a little closer to see what it was doing. It had settled on a flat black rock and had spread its wings, flattening itself as much as it could. On a chilly afternoon, it had found a way to stay warm.

As I approached, the butterfly flew up again, circling around my head, and landed on my outstretched hand. For perhaps 30 seconds, butterfly and human looked at each other, in total peace, trust, and harmony. Then the butterfly flew off and settled back on its rock, oblivious to my further movement.  If I were to commit the sin of anthropomorphism, I would say that the butterfly decided that I was not a threat, and went on with the business of warming up its body.  And if so, the butterfly was absolutely right.