A Dog Duet—Part 2

So that's the first story (cones and rods in the eyes) about the similarity between humans and dogs. The second relationship between people and our canine friends is another physiological similarity that can be considered maybe to be a little disturbing.

Researchers have noted over the last few decades that the sperm count of males—both dog and human—have been decreasing. Specifically, sperm motility—the ability of sperm to swim in a straight line—has diminished. If sperm can't swim energetically and directly toward the female egg, fertility suffers. In addition, traces of PCBs and phthalates are being found in both dog and human semen. These artificial chemicals have been linked to birth defects. Whether or not they contribute to decreased sperm activity has yet to be determined.

A comprehensive evaluation of human sperm viability has so far not been carefully and consistently measured, due to the fact that the issue is so complex for humans. Dogs are simpler, so recent studies spanning a 26-year period at Nottingham University in the UK have meticulously measured the decrease in dog fertility. It is significant.

So what is the cause of the carefully documented canine reduction in fertility? No smoking sperm gun has as yet been discovered, but the likely contributors—in light of the measured PCBs and phthalates—points to the presence of toxins and chemicals in dogs' environments as the likely causes.

Dogs are our best friends. We share much of the same living space, and we are exposed to the same chemicals they are. Thus our canine buddies may be in the same sinking fertility boat that we are. Human male fertility has been measured and is definitely on the decline, although it has yet to be adequately quantified. So it raises the question: Are we—humans and dogs—headed together towards a fertility problem? Stay tuned.

In summarizing this pair of dog duet posts: The mammalian eyes of dogs and humans—although both have evolved from those tiny mammals scurrying in the dark to avoid dinosaurs—still retain the rods and cones of those long ago times—though in different proportions. We also share a declining sperm quality. In interesting ways “man's best friend” seems to be headed down a similar evolutionary path with us. Maybe we're closer than we think; maybe more than just good buddies.

Parasitized Tomato Hornworm

The braconid wasp paracitizes the tomato hornworm, by the mother laying eggs on the worm's body. As the wasp baby pupates in these tiny tubes, it drills into the worm and eats its insides. In the lower photo the worm has collapsed into a sort of a dried-out sack. A nasty end for the worm, but we are grateful to the wasp for guarding our garden. Click to enlarge.

A Dog Duet—Part 1

I recently read two reports (sort of a duet) about a couple of current circumstances of dogs, that say something about both the qualities of canines as well as the closeness of humans and dogs—in ways that go well beyond the typical owner-pet relationship. I would argue that the old saw—that a dog is man's best friend—has a lot of truth to it. But these two reports go well beyond just the friendship concept. They tell us that there are deeper similarities; that in some ways humans and dogs share a couple of fascinating and relevant physiological qualities. Maybe we're more than best friends. Maybe we're even some kind of distant relative?

The first report described the fact that dogs are color-blind—far more than humans, but still in a physiologically similar way. Yet dogs are not really color blind; it's more that they cannot perceive the rich panoply of colors that we humans enjoy. How so? The eyes of both humans and dogs (as well as most animals) contain two kinds of light sensory receptors: cones and rods. Cones have evolved to provide visual acuity and also to respond to color, but they need rather bright light conditions to do so. Rods evolved to provide vision at low light levels and to detect motion; they do not respond to color. While human eyes contain a high proportion of cones (we see color), dogs' eyes have far fewer. Thus we see sharply, as well as perceive all the vivid hues of the artist's palette. Dogs—with more rods—have poor visual acuity but can see better than we do at night; especially being able to note motion, as their prey try to run away.

All mammals evolved to have both rods and cones in their eyes. Back when mammals were new to Earth's animal kingdom (100-200 million years ago), they were just little critters who were dominated by the much larger and more successful dinosaurs. Mammals were forced to skitter around mostly in the dark, to avoid being eaten or stepped on by the reigning dinosaurs. Needing to see well under low light levels, mammal eyes evolved lots of rods.

Think about what you see, when nighttime comes on. You can't see color—only shades of gray. There's not enough light to trigger your eye's cones, so the rods—being “color-blind”—take over. For various reasons, dog's eyes, unlike ours, have a preponderance of rods. Maybe their wolf ancestors continued their hunting activities at night. Humans, on the other hand, evolved to have a lot of cones in our eyes. We needed them—along with our ape cousins—to locate tasty and colorful fruit in our daytime foraging. Dogs mostly needed to see moving animals to chase in the dark. To compensate for their inability to distinguish colors, dogs evolved an exquisite sense of smell. With that wonderful nose they could better sniff out their food.

[As an interesting aside to dogs' and humans' eye differences, when a human is photographed with a flash, a phenomenon called “red-eye” is often observed. It is due to the light of the camera's flash being reflected off blood vessels at the back of the eye. Dogs' eyes have something called a “tapetum,” which is a mirror-like structure at the back of their eyes. When a dog is photographed with a flash, the light reflects off the tapetum and appears blue. We get red-eye, they get blue-eye.]

More on dogs and humans next time...

Praying Mantis

This little lady was in one of our spirea bushes. She sure picked a good place to be camouflaged. Click to enlarge.

Personality or Predicament?

Psychologists have argued for years now about how to interpret why people act as they do. When we observe Joe behaving in a certain way, do we attribute it to his personality or to his current predicament? Is it nature or nurture? Was Joe's action due to his inherent, peculiar character or did the particular situation he was in cause his response?

While psychologists love to bicker over the real cause, most of us ordinary folks lean towards thinking that what Joe did was due to his personality. After all, we may know, for example, that he is considered to be an extrovert (not an introvert), or he's a pretty agreeable guy (not argumentative), or he's shown himself to be conscientious (not slapdash), or we know him to be a positive dude (not negative), or to be open-minded (not intolerant). We have come to know Joe over time and attribute one or more of these possible traits to him, as we see him consistently behave in a certain (and even predictable) manner.

But wait—some psychologists will contend that Joe may, for example seem to be an agreeable guy most of the time, but didn't someone see him being quite belligerent yesterday? Maybe he was stressed out and his boss was being unreasonable, and Joe uncharacteristically flashed out. Yeah, he may be an easy-going guy most of the time, but the situation he finds himself in can control what he does.

So is it personality or predicament? There seems to be scientific evidence that both play a role—one being more important at a given time than the other. Some folks will argue that one's personality is something that can be consistently observed over time; that a person's response is even quite predictable. In the short term, however, the situation may be quite variable and thus very unpredictable. For example, Joe may most of the time be the kind of guy who always shows up on time—or even early. We can count on him to be there when the show starts. But that may be just when the situation is normal. If he had a flat tire, he could be late.

Another interesting aspect of the personality-or-predicament debate is, if personality is important, how consistent over long periods of time will that person be? If Joe has long been seen to be a conscientious guy, can we expect that behavior to persevere? Can Joe change his personality? Might he become a little careless, in his golden years? That could be considered to be a turn for the worse. Is that what happens, or do people tend to become more positive in their traits, over time?

There is a school of psychology that contends that personality is important, and that we in fact do change for the better over time. Even if we disagree whether personality is more important than the situation, we'd like to believe that we can improve with age. Shouldn't the acquisition of a modicum of wisdom over the years nudge us in the direction of change for the better? Don't we want to believe that we become more agreeable, conscientious, and resilient with age?

Whatever the case—whether personality or predicament governs our behavior—I think we can say that both are important. We are not automatons that predictably respond in a certain way. I'm a believer in free will—that we can change how we respond. We go way beyond the instinctive response that most other animals have. We are in charge, and we can change—despite how a certain situation might evoke certain feelings in us. 

Blanket Flowers

I'm growing blanket flowers for the first time this year. They're so beautiful that it'll happen again next year. Notice the beetles on the one blossom. Each blossom is about 2 inches (5 centimeters) across. Click to enlarge.

Churlish Churchgoing Children?

Religion has long been humanity's principle source of moral guidance... at least that's what most people have maintained. The conviction is that we humans easily stray from the moral path, or never find it in the first place, without following the precepts of some religious teachings. And indeed, many people have derived comfort and purpose in life from their religions.

That's why the results of a study published in November 2015 in the journal Current Biology are very surprising. The paper, coauthored by seven researchers form universities around the world, is titled “The Negative Association between Religiousness and Children's Altruism Across the World.” What this broad study discovered, after the researchers evaluated some 1200 kids (ages 5-12) from six countries, is that those kids who were religious were less likely to be concerned about the welfare of others than were nonreligious children. In other words, the prosocial behavior of religious kids was consistently found to be less than for kids raised in a secular household. That's remarkable!

The study evaluated kids who fell into three main religious categories: Muslim, Christian, and nonreligious. Besides having fewer altruistic feelings, the religious kids also were more punitive minded and more judgmental than kids raised in secular households—especially the older kids (those near 12). Another surprising result is that the religious parents who were interviewed during this study felt that their children were more empathetic than nonreligious kids—quite opposite to the study's findings.

These results are indeed surprising. Some religious people will no doubt claim the study is invalid. Atheists will, in contrast, site the results as verifying their current beliefs. Such is the behavior of a polarized world. This one study's findings are unlikely to change people's minds.

Several of the questions raised by this study, however, are important to ponder, I think. Is religion vital for moral development, as many religious people have long believed? Can people become ethical when they are raised outside a religious tradition? How can we explain the results of this study? Why is it that nonreligious kids were found to be more prosocial? Does religion really have a corner on morality? Do these results suggest further studies that may shed more light on the issue? (Such controversial results always do.)

The authors did not attempt to interpret their findings—that would go beyond the scientific bounds of their work. Their intent was not to explain why these findings occurred. (We might look to philosophy for that.) Despite the fact that some people would take issue with their results, the study followed rigorous scientific protocol and they did interview a wide spectrum of children. More insights may come in the future. The findings certainly go against the grain of society's long-held beliefs. I think it is simply useful to hear about these unexpected and contrary results and to open our minds to the possibilities they may imply.