Tiny Brain -- Large Intelligence or Natural Evil in Deep Time?

Updated: Nov 21, 2021

We commonly associate intelligence with advanced brain development, even with large (mammalian) brains of chimpanzees and dolphins, creatures well-known for their intelligence. Conversely, we do not expect intelligent behavior from tiny brains. Yet, the fauna of Africa, Australia, India, Nepal, China, and Southeast Asia features a predator whose hunting tactics seem highly intelligent despite a miniscule brain, substantially smaller than a pinhead.

When hunting common prey, their behavior is instinctive, but not when they meet unfamiliar prey or unfamiliar situations. Then they exhibit remarkable capacities to improvise by trial and error and remember their new tactics. When they try something new, they obtain feedback about success, and failure; when they encounter dangerous prey, they will find the best angle of attack, often via detours, whose preparation can take as long as an hour. The creature is only five to seven millimeters long with a brain consisting of about 600,000 neurons (the human brain contains 86 billion). If you are by now curious about the name of this creature, it belongs to the genus of jumping spiders (Portia fimbriatus). It has eight eyes and extraordinary vision (almost 360 degrees) over 75 cm (30 inches) together with the sharpest close-up vision. Feeding on other spiders, their hunting behavior has greatly surprised scientists during lab studies at Cambridge university.

The results? There is much more to spider brains than previously realized, and when it comes to cognition and complex mental processing, jumping spiders are among the champions. Their usual technique is known as “stalk and pounce,” quite distinct from other spiders that wait in a web for the meal to arrive. Using their high visual acuity, they scan their environment at a distance for prey, predators, and mates.

If that’s not remarkable enough, many of their behaviors are outright devious. When hunting another group of hunting spiders that habitually build nests in curled up leaves which they suspend on strands of silk, the hunter mimics the male behavior of that type to lure the female out of nest into a deadly ambush. They also hunt web building spiders and have developed an arsenal of tricks depending on the size of the prey. Shaking the web in just the right way, lures the resident spider from the center to edge, where it is ambushed. If a resident spider is relatively small, the hunter will mimic a trapped insect, bringing the prey within reach of the clever Portia who eats it. Lager spiders are treated ambushed more cautiously. The Portia will rock the web gently on a single strand at the edge of the web. When the owner moves slowly in that direction to inspect, Portia’s venomous fangs are ready. At times, the tiny creature will use an even more sophisticated trick. It will shake the entire web like a gust of wind that camouflages its slow-motion crawl towards its prey. Other experiments have shown that Portia is capable of mental presentations and is good with numbers, equivalent to a one-year-old child.

What brings such an arsenal into play is what we call the food chain. All creatures are more or less food for others. They lead a life of precariousness, daily threatened to become prey of other predators. In Portia's case these are birds, lizards, frogs, other spiders. Beyond theses, Portia is particularly vulnerable to be chosen as food for the offspring of wasps that lay eggs into a live spider, locking them up in the wasp’s nest where the victim is slowly eaten alive by the hatching larvae.

This raises at least three important questions. (1) Since we call catastrophic weather events, tectonic plate movements, earthquakes, and tsunamis “natural evil,” does the same term also apply to naturally occurring deviousness (remember the jumping spider, along with other spiders, evolved 250 million years ago)? (2) Or are these events simply the outworking of a "best possible creation." (3) Whatever your answer, have you tried to relate it to your view of the Creator?

I would be interested in your comments.


If this post awakens your interest in exploring the relation of Science and Christianity, you can purchase my book Cosmos and Revelation: Reimagining God's Creation in the Age of Science here.

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