What conditions support the evolution of intelligence?

15 04 2009

Good tidings and well-wishes!

One of the several books I’m currently reading is “Elephants” by Joyce Poole. While it’s far less technical than my usual literary fodder, it’s nonetheless a decent and engaging introduction into the study of modern-day proboscideans (my favorite order of mammals, as evidenced by the heading atop this blog). Long-time readers of mine will recall that I find the subject of non-human animal intelligence fascinating and, to a large and frankly appropriate degree, humbling. Here are a few examples of highly intelligent and perceptive elephantine behavior Poole cites in her book:

-“Elephants have been known intentionally to throw or drop large rocks and logs on the live wire of electric fences, either breaking the wire or loosening it so that it makes contact with the earth wire, thus shorting the fence.” (pg. 36)

-“Elephants also use tools that they find in their environment. Elephants will hold a stick in their trunk and use it to remove  a tick from between their forelegs. They may pick up a palm frond or similar piece of vegetation and use it as a fly swat to reach part of the body that the trunk cannot. Elephants may pick up objects in their environments and throw them, under trunk, at their enemies or playmates with surprising accuracy.” (pg. 38)

Furthermore, modern elephants have been observed burying their dead and even pay them vigil and respect:

But what interests me most about Poole’s book thus far is the following sentence: 

“Perhaps, as in humans where the development of the brain paralleled the evolution of upright posture and the freeing of a dextrous hand for tool use, the complexity of an elephant’s brain may be related to the use of its trunk.” (pg. 38)

While this explanation suits homonids, and proboscids quite nicely, what about notably intelligent creatures which lack such dextrous appendages? How did their sapience evolve, and why?

Before proceeding, I must admit that I am by no means an expert in this area. That being said, I haven’t discovered much literature on the subject, so I’ll record my own observations and interpretations based thereon below. If anyone with superior expertise sees any flaw in my reasoning, please don’t hesitate to reply and I’ll promptly incorporate your observations in the form of updates.

Alright then…on to the fun part:

-The ‘dextrous appendage’ argument likely applies to cephalopods (squid, octopi, cuttlefish, and nautili) as well, given the widening range of functions demonstrated by their tentacles.

-Many scientists argue that cetaceans (whales and dolphins), and odontocetes (toothed whales such as dolphins, orcas, and sperm whales) in particular, may actually surpass humans in intellect. I infer that the evolution of this spectacular mental prowess may be largely due to their intricate dependency on echolocation, which requires a complicated and advanced brain to visualize the feedback, combined with their strong social tendencies. I’ve noticed that, in general, the more social an animal is, the more intelligent it is (though there are obvious exceptions such as the aforementioned cephalopods). Other examples of social animals displaying remarkable intellect include iguanas and ants (the latter display a sort of collective intelligence).

-Though I covered ravens in an earlier post, I have a few additional thoughts on why they may have acquired their infamous brain-power. Ravens consume a highly diverse diet, consisting of everything from carrion, to rodents, to human garbage, to berries, which may have something to do with it. Perhaps extreme omnivory is related to heightened intelligence. After-all, if you eat nearly anything, you run the risk of devouring something toxic or indigestible. Thus, such creatures require heightened skills in memory in order to recall which foods are unsuitable for their consumption. It’s not surprising, therefore, that the animal kingdom’s most famous (relatively) indiscriminate eaters,  pigs, are quite intelligent. Racoons, also known as natural garbage disposals, are comparable in this regard. In the case of ravens, their intellect may also have been driven in part by their comparative ecological disadvantages to raptors and herbivorous birds since they lack the weaponry of the former and the small size of the latter. Thus, their sagacity may have been the sole factor which enabled them to compete with these avian counterparts and thus was developed through natural selection.

Therefore, as I understand it, the factors which drive and encourage enhanced mental capacities are the development of a dextrous appendage, participation in a complex social group, the utilization of intricate techniques to locate food (such as echolocation, although this article concerning bats suggests that this isn’t as significant of a factor as many of the others), the adoption of an extremely-omnivorous diet, and the lack of any other methods with which to compete with rival organisms.  In most instances, however, it would appear that a combination of these elements is responsible for this development.

This post would be incomplete were I to ignore the philosophical implications of this phenomenon (I realize that this is a scientific blog, however the successive information is quite relevant and thus will be included despite its contextual differences) . We, as humans, frequently flatter ourselves as being the only sentient organisms on the planet. In consequence of this, we also tend to deify other creatures and proclaim them ‘morally superior’ to ourselves simply because, so the twisted logic goes, they lack the mental capacity to be scheming or unscrupulous. The above information destroys the first argument. As for the second, consider this: chimpanzees will commit unprovoked murder and maintain a scandalous, cutthroat political system which would make even the most corrupt lobbyist or wing-nut extremist cringe. Furthermore, it’s no secret that ants will go to war and some species even organize torture of enemy combatants. In Bernd Heinrich’s “Mind of the Raven” (to which I provided a link earlier in this post), in response to his observation of a group of captive ravens murdering a newcomer, he writes: “The murder was probably punishment for repeated infractions. Feelings of outrage that are used to justify cruelty are reminiscent of our own behavior, and have been a source of human suffering the world over. We cannot expect more from ravens.” (pg 272)

May the fossil record and the rest of the natural world continue to enchant us all.




2 responses

13 06 2009

To the social and using prehensile organs, you can of course add parrots. Sociality appears to be the default for them (there are very few exceptions), they make use of their feet as manipulative organs and their beaks can be used in numerous ways. Also, the beak of parrots is only attached to the skull by means of a joint that allows it quite some movement. The thick, muscled tongue is probably an integral part of the beak as a manipulative organ.

14 06 2009

You’ve raised an excellent point, Brian! I was aware of heightened intelligence in parrots (as exemplified by the now-famous ‘Alex’ experiments) but completely ignorant of their unique beak attatchment. Indeed, these birds are certainy deserving of being added to any discussion on inhuman intelligence and its evolutionary roots.

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