October 16, 2016

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SPIDER MONKEYS IN FRONTERA COROZAL
On October 5th when I was in Frontera Corozal, Chiapas, on Mexico's southern border with Guatemala, getting a new visa for Mexico, that wasn't my first brush with spider monkeys. Most recently in Ría Lagartos Biosphere Reserve on the Yucatan's northern coast we got to see them escaping through the trees, resulting in our page on the species at https://www.backyardnature.net/yucatan/monkey.htm

However, the Frontera Corozal encounter certainly was my closest look at them yet, and that's encouraged me to learn more about them. You can review what the spider monkey who paused above my tent that afternoon looked like at https://www.backyardnature.net/n/16/161009hm.jpg

And that one's hard-to-interpret "grin" can be wondered at, at https://www.backyardnature.net/n/16/161009hn.jpg

Something new I've learned is that spider monkeys in general -- species of the genus Ateles -- are among the smartest of primates. A 2007 study found that only humans, orangutans and chimpanzees are smarter. It's suggested that the spider monkey's acute intelligence may have arisen because of their fruit-eating, or "frugivorous," diet, which requires them to identify and memorize many fruit types, and to remember the fruits' locations.

Despite their intelligence, spider monkeys don't make tools. That coincides with the fact that their hands bear only vestigial thumbs, thumbs being handy for handling tools. This near-thumblessness is a feature of the entire genus Ateles, the name Ateles meaning "imperfect," referring to the hands lacking decent thumbs.

At my campsite in Frontera Corozal I first noticed the spider monkeys when a tremendous roaring irrupted nearby. I recognized the roaring as that of howler monkeys but when I looked around , I saw only spider monkeys. However, there wasn't a chance that I was confusing the calls, because spider monkeys simply don't roar. They're described as producing barks, whinnies, squeals, squeaks and screams, but no roars. During my stay among them I never heard any of their vocalizations, just the rustling of leave as they moved among tree branches above the tent.

Monkeys also communicate with body language, so I tried to look up what the "grin" in our photo might have meant. I found nothing about that, but I did learn that Geoffroy's Spider Monkeys curl their tails or arch their backs in order to threaten. If one shakes its head, either it's a threat or an invitation to play. If the species shakes tree branches or sways its arms about, that's a warning of danger to the group

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MORE ON BURRO & HORSE DIGESTION
Each day I continue to be struck by how the burros relish eating such large amounts of the weeds I pull up for them, weeds often with semiwoody or woody stems and roots.

Animals that eat a lot of such high cellulose food depend on bacteria living in their guts to ferment the cellulose. The fermentation breaks down the celluse into simpler compounds more easily digested and absorbed into the body.

The stomachs of many animals that eat high cellulose food have a bag-like extension on them called rumens. When hard-to-digest food is swallowed, it collects in the rumen and then later can be burped up and chewed again. Also, while incompletely chewed food resides in the rumen, fermentation takes place. Cattle are the best known "ruminants." Fermentation in the rumen is often referred to as foregut fermentation.

In contrast, the guts of burros, horses, as well as elephants, rhinoceroses and such small animals as rodents and rabbits lack rumens, but instead at the end of their guts their large intestines lead into a large "cecum," where fermentation takes place. The cecum isn't like a stuck-on bag, but rather a ballooning cylindrical extension of the large intestine. The cecum lies between the large intestine and the rectum. Fermentation in the cecum can be called hindgut fermentation.

At first glance, cow's foregut fermentation, with the cow's ability to re-chew its food at its convenience, and prepare food better before it enters the stomach, seems much more useful than a burro's hindgut operation. Is this a matter of ruminants such as cattle being more highly evolved than burros and horses?

Not necessarily. For one thing, the burro's hindgut fermentation, with no need to spend extra time re-chewing food, enables the burro to wander over large areas eating small amounts of low-quality forage all day long. Thus burros can survive in scrubby habitats where more sedentary ruminants, like cows with their foregut fermentation, need higher-quality food, such as that in grasslands and meadows, in order to get enough nutrition from the food in their relatively small feeding area. And scrubby environments are more commonly encountered than lush grasslands and meadows.

In fact, over the course of evolution animals of relatively large size have most benefited from hindgut fermentation simply because cecums tend to be bigger than rumens, and thus can hold more undigested food. The largest prehistoric herbivores, or "megaherbivores," such as elephants and indricotheres (types of rhinoceros), were hindgut fermenters. Sometimes the simple approach is also the most effective approach.

Not only certain kinds of mammals are hindgut fermenters with cecums, but also several insect types have them -- the best known being termites. Digestion of wood particles in certain termite species is accomplished inside microorganisms called gut flagellates, while on other species bacteria decompose the cellulose.

One reason the burros seem to like my pulled-up weeds more than anything else is that they definitely want a varied diet. If a wheelbarrow of freshly cut tree branches of a kind of tree they're known to like, such as those of the Bean-Family member Uaxim (Leucaena leucocephala, is dumped in their food bins, the burros will eat a little, then stop, even though I know they're still hungry. But if I arrive with a mixed selection of weeds, they'll run to eat them. Sometimes while they're eating the weeds, they'll swing around and take a few bites of Uaxim, proving that they have nothing against Uaxim, just that they want diversity.

Well, nutritionists tell us humans that a varied diet is best, and burros seem to know that intuitively.

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DISCONNECTING & THE BRAIN
At the rancho, with no electricity and no Internet, I've had to adjust to the fact that in my previous life, as I became more and more a citizen of cyberspace, increasingly I shifted part of my brain function into cyberspace. I'd grown accustomed to limiting my biological brain to remembering key words and concepts, but storing details associated with those words and concepts in cyberspace -- my BackyardNature.Net website.

For example, I'd learn about a plant or animals, write about it and upload a page about it to the website. As long as I remembered the organism's name -- its "access code" -- later if I'd forget, say, how a certain herb might be used medicinally, I could always look it up on my website. At the rancho I can't look things up. Therefore: By coming here have I've abandoned an important part of my brain, and in that way diminished myself?

The question makes sense to me because I believe that animal brains are no more than very sophisticated computers. It's just that our animal brains are organic, based on carbon atoms, while mechanical computers are inorganic, largely based on silicon, at least the computing parts.

Also, I believe that we "are" exactly what our brains tell us we are. If I get religion and start believing that I'm a special existence in a Universe that's just a stage in which I'm to be judged as to whether I handle things in a good or bad way, it's my brain telling me that this belief system has become part of what I am. And if I suffer brain damage that permanently wipes out all memory acquired before I got religion, I'll "be" what I was before my conversion, because my brain will be silent on the matter. Therefore, if I walk away from my silicon-based remote brain on the Internet, which if nothing else informs me that I am the author of all that information about plants and animals, aren't I losing something of myself?

As I've thought about this, I've surprised myself by deciding that the answer depends on how convinced I remain that cyberspace with its vast network of interconnecting nodes and multifarious information inputs is itself a kind of brain, and that in fact the Earth with all its evolving things (Gaia), and also the whole Universe with its majestically flowing currents of information and means of storing that information -- information stored in configurations of molecules, relationships between energy and matter, life forms remembering and passing on information, etc. -- also is a brain. If that's the case, the previous brains mentioned here are less brains themselves, than components similar to discreet sections of a human brain which join together magically to create awareness, insight, inspiration, etc. The higher level the organization, the more profound the mentality.

So, yes, by withdrawing from that part of my brain now suspended in cyberspace I am stepping back from part of myself.

Deciding that, now the matter becomes more nuanced. I'm still somewhat invested in cyberspace, as this Newsletter attests. Now the question becomes where the Middle Path is between no involvement with cyberspace, and too much.

One reason to suspect that the Middle Path may reside nearer to "no involvement" than "very much," is that Nature teaches that vulnerable environments periodically suffer catastrophic events. The human-made mass extinction of Earthly life forms occurring right now is at least the sixth major mass extinction in the history of Life on Earth. In this light, cyberspace, entirely dependent on today's ever-more-stressed and erratically evolving societies, seems like a dicey place for storing part of one's brain.

So, I'm not too worried about losing my silicon-based brain section, even as I don't feel too smug about having disconnected. As usual, after all that thinking, the only advice for living life I find I continue to have total confidence in is this:

That I should pay attention to what this very moment is all about, and live in this moment as vividly as possible.

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Best wishes to all Newsletter readers,

Jim

All previous Newsletters are archived at https://www.backyardnature.net/n/.