Wednesday, October 18, 2017

Playing 'Possum

We recently had some kind of critter invade the garden in the night and gnaw off tomato seedlings and other vulnerable young vegetables. We struggled with protecting the delicate plants, as we tried to figure out who was the culprit. We at first suspected rabbits, but after several failed attempts at intercepting and identifying the perpetrator, we bought a live trap. The very next morning I entered the garden to greet a very unhappy opposum staring at me from his cage. I drove him up the road a few miles and released him into the woods.
That incident led me to do some investigation into the Virginia opossum, hoping that I could figure a way of discouraging these critters from invading the garden in the future. We have been growing vegetables for over three decades now and this is the first time opossums have raided us. We've dealt with voles, rabbits, countless insects, and deer, but the opossum was a new threat.
The local opossum (Didelphis virginiana) is North America's sole marsupial—which is a type of mammal that lacks a placenta. Like kangaroos, the opossum gives birth to tiny fetal-like creatures, who scramble into mom's pouch, where they spend their first few months of life. The opossum looks like a rat with a very long, pointed head. It's about the size of a domestic cat, but its brain is only one-third of the size of a cat's brain. (Now, that's really dumb! I've written on this blog a few times about how the cognitive capability of the household cat is quite inferior to a dog.)
The opossum is a nocturnal creature, rambling around in the night for its food. Its nose is extremely sensitive, which compensates for its poor eyesight. It is truly an omnivore, as it will dine on grains, snakes, mice, chipmunks, human garbage, insects (ants, ticks, flies, spiders, etc.), as well as tender vegetables. That last item spurred this blog.
Most Americans are familiar with the term “playing 'possum,” which refers to the animal's habit of suddenly falling down and playing “dead” when it's threatened. It does a remarkable job of looking dead. Its eyes are open, its tongue flops out, its heart rate halves, its breathing rate drops by a third, and it oozes a foul-smelling liquid from glands near its anus that reeks of death. It can lie lifeless for up to six hours.
The opossum is a hairy critter (rat-looking, as I said) with a hairless tail that looks eerily like a snake. It has more teeth than any other similar mammal. What's especially unique is that it has an opposable thumb on all four feet; making them look uncannily like human hands. It's a very bizarre little critter!
Another fascinating fact about the opossum is how it came to North America. Millions of years ago North America was inhabited only by placental mammals, while South America's mammals were predominantly marsupial. About three million years ago the Isthmus of Panama arose as sea levels dropped, connecting the two continents. Some marsupials migrated north; some placental northern mammals headed south, through Panama.
Thereafter, similarly-behaving species (one kind marsupial, the other mammal) came into competition, and when they did, the placentals almost always had the advantage. As a result, many marsupials in South America went extinct, giving way there to their placental competitors. In North America, all marsupials went extinct, except for the intrepid opossum. Maybe its ability to play dead so effectively helped it to persevere?
I find it fascinating that we humans evolved from placental mammals—primates—who resemble the opossum. It makes me wonder what if the marsupials had been more fit than placental mammals, and they had won the evolutionary competition? Would the world's most intelligent critter today be a marsupial with opposable thumbs? It's a reminder that, if we could roll back the clock a few million years and replay evolution, today's mix of species would be very different. The fact that humans came out (so far, anyway) as the dominant species was not preordained.

Sunday, October 15, 2017

Highland Cows

A friend in Scotland sent me these photos of highland cow calves. Could anything be cuter? Click to enlarge.

Tuesday, October 10, 2017

Untiring Attention

Many years ago I discovered the French naturalist Henri Fabre, who, in the latter half of the 19th century painstakingly and relentlessly studied insects and wrote about them. Charles Darwin paid tribute to Fabre and his many contributions to the science of entomology. Fabre spent countless hours on his knees studying many kinds of bugs and recording his observations. Those observations are often delightful to read.
There are two contrasting types of scientists who devote their lives to the natural world. The first type is usually formally educated, takes a position on the staff of an institution of higher education, and writes academic papers in his chosen field. The second type is often not formally educated, may have no academic employment, and devotes most of his time to field observation.
Of the first type, we have as examples such eminent individuals as Isaac Newton, Albert Einstein, and E.O. Wilson. Three examples of the second type are John Muir, Charles Darwin, and Fabre. The third individual in each case focused their work on insects.
Both Wilson and Fabre are people for whom I have enormous admiration, and have learned much from each of their studies and writings. I think what especially elicits my appreciation for the kind of naturalist that Fabre was, is the deep devotion and untiring attention he put to his work. In fact, what he accomplished should not really be described as work, but as passion. What drove him on (as well as Darwin and Muir) was not the desire to hold an esteemed academic position, or publish papers, but simply the urge to discover nature's ways. They were not driven to publish, but to watch.
I do not wish in any way to disparage the college professor who spends the majority of her time on campus, teaching, or writing papers. Science has benefited greatly from the work of academics. College professors often collaborate with fellow academics and form teams that tackle problems that individuals can't. College professors also have access to expensive resources—such as supercomputers and complex experimental machinery—that individuals don't. So they make invaluable contributions to knowledge.
An individual investigator like Fabre, Muir, and Darwin has his own advantage: freedom from academic dogma and institutional thinking. They can follow their own intuition. They are often obsessive people who are untiring in their attention—with a singular devotion to pursue their zeal to their heart's content. Darwin's extraordinary insights into evolution came after decades of dogged pursuit. Muir's advocacy for the need to protect nature's beautiful places followed decades of courageous and dangerous travels through the wilderness. Fabre's delightful discoveries came after decades of squinting at tiny bugs and getting sore knees.
I value both kinds of scientist—the academic and the field naturalist. Indeed, some scientists are both kinds. Maybe I lean a little bit toward the loners like Fabre because, living as a hermit, I treasure solitude. Besides, curious people like him inspire my own investigations in my own corner of the wilderness.

Wednesday, October 4, 2017

Alien Intelligence

The search is fully on for signs of intelligent life on planets other than Earth. Humans have long pondered whether or not life arose elsewhere—and in particular, if it could be intelligent life. Up until the last couple of decades, this conjecture was little more than idle speculation. But now we have telescopes that have discovered thousands of planets circling nearby stars—some of those planets might harbor life. Additionally, our definition of the extreme conditions under which life can survive has greatly expanded, so we can now expect to see life surviving under fierce conditions that we once thought were impossible. More and more, it seems that the discovery of extraterrestrial life is more a matter of “when,” not “if.”
Very recently there's been yet another finding in this arena—right here on Earth—of a new type of intelligence that was under our noses, but was never before recognized. This finding is very similar to recent discoveries of terrestrial lifeforms—dubbed “extremophiles”—that thrive in conditions we once considered to be too hostile to allow life. The new discovery is a species of ocean critters called ctenophores (pronounced ten-o-fors) that are intelligent creatures who evolved their brains and nervous systems in a very different manner from the rest of Earth's species. They are some kind of alien.
From the earliest understood forms of Earth life, all the way up to us humans, the progression of nervous systems from primitive cells to the human brain have followed what we came to believe was a singular path. All life's nervous systems (so we have believed) genetically evolved to employ common neural messengers, such as serotonin, dopamine, and nitric oxide. This mechanism is the same, from nematodes to ants to humans. We've all evolved our nervous systems in the same fashion.
A Russian scientist (Leonid Moroz) who emigrated from his native land to the US two decades ago, insisted upon looking more deeply into the qualities of ctenophores. These critters had been identified and cataloged for a long time—and were considered to be a close cousin of jellyfish. When Moroz captured a few of these critters and began examining them, however, he found that, although they had evolved muscles and a nervous system like other creatures, they took an entirely different route from all other life forms.
Ctenophores are a very ancient life-form. They display an example of what is called convergence: life evolving into similar-looking critters, but doing so by following a different evolutionary path. For example, eyes have independently evolved many times, following parallel but quite different evolutionary paths. Porpoises and sharks are very similar creatures, but evolved through completely different paths. One is a mammal, the other is a fish. In the case of the porpoise and shark, we find very different critters which arrived at the same solution, because—although they started at different beginning points—they each had to solve the same problems: swimming.
What is fascinating about ctenophores is that, had their singular evolutionary route been favored by nature, life-forms on Earth today would be very different. Life would likely have eventually still evolved nervous systems and sophisticated brains, but they'd be housed in quite different kinds of animals. There would be no humans, as we know them.

This discovery has relevance to our search for extraterrestrial life. Just as the existence of extremophiles has caused us to open our minds to other kinds of life elsewhere, ctenophores seem to be advising us to open our minds even more, to understanding that intelligence may have evolved in alien ways that we have yet to understand, and to be on the lookout for some strange possibilities. We can learn from aliens right here on Earth.

Sunday, October 1, 2017

Orange Caterpillar

I found this caterpillar a few days ago. It's about 2 inches (5 cm) long. Click to enlarge.

Thursday, September 28, 2017

Altruistic Exchange

Social psychologists describe a very nice quality that we humans possess—something that is planted deep in our psyche; something that has been bred into us by evolution: a natural inclination to reciprocate kind behavior when it is shown to us. If someone does something nice to us, we feel an urge to return the favor.
However, there's another, negative side of the coin: when someone mistreats us we often have an equally natural inclination to reciprocate with like mistreatment. Revenge is a deep instinct of ours. Indeed, much of human history is replete with violence, as humans often strike back, in retaliation. Although that is an important topic on its own, I will focus here on the positive side of the coin: our returning favor for favor.
It makes sense that we feel a yearning to return kindness with kindness, when we consider it from an evolutionary perspective. When our deep ancestors reciprocated the altruistic behaviors of community members, it pulled the community together. The clan became stronger and more cooperative. It strengthened the group, so that they survived better than clans who didn't cooperate. The noncooperative group went extinct, while the altruistic group thrived.
So altruistic exchange strengthens our connections to one another. And thanks to evolution, it's literally in our genes. We are thankful for it and enjoy its benefits. That said, there's a bit of a problematic side to friendly reciprocity: it opens us up to being scammed. Salespeople have known this and have cleverly used it for ages. If, as a salesman, you offer someone a token favor, you've earned a little leverage to get them to cooperate with you. Thus, the reciprocity tendency can be used to manipulate people and sell them stuff they'd otherwise not want.
Salespeople are often extremely solicitous before they sell you their product. They are your best friend; they have all the time in the world to be with you; and they're apt to gift you with little mementos. Once you respond and buy, however, attempts to reach the formerly friendly salesperson—if you have a question or a complaint—very often go unanswered.
As another example, we may get “free” offers from salespeople to enjoy a gratuitous meal, in exchange for the “opportunity” to purchase a time-share condominium in some idyllic location. Watch out! After the free meal, you will be forced to endure a coercive session, where you will be expected to return the favor of a meal by buying your very own condo.
But to return to my starting point: we are genetically programmed to reciprocate, when someone does us a favor. It's nice to be able to respond in kind. There are, however, times when we can't return the kindness to the individual who benefited us. What do we do then? How do we deal with the propensity to respond kindly, when we can't? Many people say that the right thing to do is to pass it on to others. That's an honorable thing to do. The “Pay it Forward” movement arose years ago to do just that. The reciprocity of kindness to others can spread around, to the benefit of everyone.
So which side of the coin predominates in society—returning kindness or revenge? That's an argument that I don't wish to wade into here. I'd just like to recognize and celebrate the fact that altruistic exchanges are inherent in us and that we all can benefit from this natural positive urge.

Saturday, September 23, 2017

Dung Beetle

I found this guy in a bucket of water by the outdoor tub. He was a along way from his favorite plaything: a round ball of poop to roll home. He did pause long enough for me to get a photo. He's almost an inch (2 cm) long. Click to enlarge.