How Many Brains Does a Creature Need?

Leeches have 32 brains. Well, sort of. Each of its separate segments contains its own neuronal ganglion. As one answer on Quora puts it, "precisely it does not have 32 brains but a single brain that exists in 32 parts throughout the body," yet because each ganglion works independently, we might say it literally has a brain for each segment.

Is It True That a Leech Has 32 Brains?

Here's a page with thirteen wild and wonderful facts about animal brains:

13 Facts About Animals' Brains

Starfish have their neurons distributed through their arms instead of concentrated in a central location. A spider's brain is too big for its head and extends into its legs. Octopuses, similarly, keep two-thirds of their neurons in their tentacles instead of in the central brain. Thus, like spiders, they can perform amazingly complex feats with their limbs. The octopus, in fact, has the highest brain-to-body mass ratio of any invertebrate. This article explores octopus intelligence, including their ability to use tools:

How Smart Are Octopuses?

On the other hand, although we consider ourselves the planet's superior life form because of our intelligence, the humble sea squirt doesn't appear to value brainpower very highly. In the transition from its immature, mobile phase into an adult rooted in one spot, it "eats" its own brain. Among other animals that seem to consider brains optional, a cockroach can survive a long time with no head (until it starves to death). Then there's the famous case of a chicken named Mike, who lived for eighteen months after being (mostly) decapitated:

Mike the Headless Chicken

So maybe we members of the species Homo sapiens ("wise human") should be a bit more modest about the power to rule Earth through our intelligence? Maybe alien visitors would single out ants or termites as the dominant species, since there are so many more of them than us, and their excavations produce significant effects on the landscape. Or how about grasses? Not only do they cover much of the globe, they obviously employ us as their servants to help them spread and thrive.

Margaret L. Carter

Carter's Crypt

Weird Insect Sex

I recently read a fun, clever SF romance called STRANGE LOVE, by Ann Aguirre. On Zylar’s world, overpopulation has led to stringent restrictions on mating and reproduction. Adults seeking mates have to participate in the Choosing, a rigorous series of trials. Having failed in four Choosings, Zylar has one more chance, or he’ll be sentenced to life as a drone, neutered and relegated to menial tasks. As the novel begins, he travels to a distant planet to meet the potential mate with whom he has been corresponding. It’s not unusual for members of his species to mate with aliens, since actual conception of offspring occurs through high-tech gene manipulation. However, a solar flare storm has damaged his ship’s AI, as a result of which he unwittingly ends up on Earth. He finds the female he mistakes for his prospective mate in the middle of an apparently devastated landscape, actually the aftermath of a battlefield reenactment weekend. He scoops up Beryl Bowman and her dog, Snaps. Even though Zylar is basically a humanoid insect, he and Beryl fall in love, and eventually they enjoy erotic intimacy despite the differences between their biology. His species has a decidedly bizarre reproductive physiology, which Aguirre based on a genus of cave-dwelling Brazilian insects.

In those four species of the tiny Neotrogla, females penetrate males with a penis-like organ called a gynosome. "Once the female has penetrated the male, her gynosome inflates, releasing a set of spines that can be used to keep the male from escaping. The sex lasts forty to seventy hours." This is a rare case in nature where the female has the ability to coerce the male into sex, the reverse of the usual power balance. In addition to collecting sperm from the male, the female receives nutritious "seminal gifts" to nourish her for the benefit of her eggs. Biologists theorize that this system evolved because of the scarcity of food in the insects' dry, barren environment. Here are a couple of articles about the weird sex lives of Neotrogla:

Scientists Discover the Gynosome

The Females Wear the Penises

In most animal species, sexual selection makes females the more choosy sex, while males will mate with any available and willing female. Those cave-dwelling insects reverse the typical pattern, with males being more picky and females competing for them. This page discusses animal sex-role reversal in general:

Wild Sex

So for SF authors who want to devise unique methods of alien reproduction, Earth biology includes potential models far odder than the well-known pregnant male seahorse—including females with "penises" and males with "vaginas." And I definitely recommend Aguirre's STRANGE LOVE; it's ingenious, suspenseful, often humorous, and sometimes sensual.

Margaret L. Carter

Carter's Crypt

Insect Consciousness?

A honeybee scientist, Andrew Barron, and a philosopher, Colin Klein, have collaborated on a study that suggests insects may have consciousness and emotions:

Insects Are Conscious

Does insects' inner life comprise more than simple reflexes? Conventionally, the neocortex is thought to be the site of consciousness. Suppose, rather, the "much more primitive midbrain" synthesizes experience into "a unified, egocentric point of view"? Barron and Klein maintain that insects have midbrain-like neural structures that enable them to "model themselves as they move through space." (The quotations come from an article about this study in SMITHSONIAN magazine.) Insects may feel, at the very least, hunger and pain.

Since I've always shared the prevailing belief that invertebrates don't have enough neural processing capacity to feel anything, this hypothesis strikes me as rather unsettling. Insects do appear to "plan," in a sense, in that they pursue definite goals. They can learn from experience (even flatworms, a much "lower" life form, can do that), so do they have "memory"? They make choices between alternatives, so are they "deciding"?

Whether insects have consciousness and the ability to think depends, of course, on how we define "conscious" and "think." C. S. Lewis in THE PROBLEM OF PAIN points out that an unconscious human body may reflexively react to hurtful stimuli although obviously without being aware of pain. If by "self-awareness" we mean the ability to meditate on our own existence, possibly only human beings have that quality. Self-awareness on the level of recognizing one's own reflection in a mirror is confined to us, some primates, and a select few other animals. If "thinking" means only abstract thought that can be formulated in words, by definition we classify ourselves as the only thinking organisms on the planet. If any kind of problem-solving equals thinking, the field becomes much wider.

I once read a story (can't remember the title or author) in which one character tries to convince another that thought isn't confined to human beings and higher animals. He says, "With what does a plant think, in the absence of a brain?"—classifying a plant's phototropism as a form of thinking.

Barron and Klein hope investigating the mental lives of insects may throw light on the origins of subjectivity in "higher" species, including ourselves.

Margaret L. Carter

Carter's Crypt