Sam asked Dorp, “How does the plant put water in its cells without the water gooshing back out when they get full?” 

“Well Sam, plants have a special way to intake and retain water. This process of plants taking on water through the roots is called osmosis. Once in the root, the water moves up the stem of the plant via capillary action. Then the tiny pores on the leaves open up and the leaves begin to lose water. This is called transpiration, when water evaporates from the leaf of the plant. There is a lot more to learn about this, but I would have to use words like xylem, hydraulic conductivity, apoplastic barriers, and the like. For right now, just understand that roots drink water through osmosis and the leaves lose water through transpiration, OK?” 

“Hmmm,” Sam pondered, “So transpiration is when plants sweat, huh? I guess we are about to be sweated out of this dandelion. Oh. Look at the rabbit. What do you call 10 rabbits hopping backwards together?” 

“I don’t know, Sam.” 

“A receding hare-line. Ha!” 

Dorp ignored the joke, “After a fashion, plants sweat. So far, you’ve heard four terms of water movement: precipitation, percolation, osmosis, and transpiration. We dropped to the earth via precipitation, trickled down into the ground through percolation. We were absorbed into the roots by osmosis, and we move out of the plant via transpiration. Plant material, called cellulose, has a certain water level it tries to maintain, whether the plant is alive or dead. Even a dead plant will absorb water when it rains. Its cells try to stay damp, like your mom’s kitchen sponge. When it absorbs all the water it can, it’s called the saturation point.” 

“So, plants have cellulose, hmmm? My mom says she has too much cellulose on her thighs." 

Dorp corrected Sam: “I think she meant cellulite, not cellulose.” 

“Mr. Dorp, she sat on my lap once, and there is nothing light about it. 

Oh. And now we move to the end of the leaf and are transpired, eh?” 

“Yes, if that horse doesn’t eat us first.” 

Sam looked up and saw the horse grazing, moving closer and closer, like an eating machine moving side to side. He had seen horses before, but not from this angle. “Mr. Dorp! I don’t want to get chewed up.” 

“You are water,” Dorp explained, “Water doesn’t get chewed.” 

Sam was not comforted by this news: “But I don’t want to be eaten! I don’t want to go inside of a horse.” 

“You are now water. You have no control. This is what we do.” 

Sam couldn’t understand how Dorp could be so calm all the time. He was like a combination of President Coolidge and his Uncle Steve. Suddenly, it got dark. Sam heard a crunching sound. He felt himself being lifted into the air as the horse raised his head to swallow the dandelion. Sam felt himself getting even wetter. He complained to Dorp that the water felt slimy. 

Dorp spoke: “You are feeling the horse’s saliva. Horses produce up to 10 gallons of saliva a day, and it is 99.5% water.” 

“Horses make 10 gallons of spit a day?” 

“No Sam, unlike camels, horses don’t spit. Since horses eat vegetation, they need saliva to moisturize the ingesta as it is called. They mostly eat grass, hay and grains. Digestion begins in their foregut.” 

“What is a foregut?” Sam asked. 

Sam was already getting tired of this learning on what was supposed to be summer vacation. Maybe the school librarian would give him extra credit on the summer reading program. 

“Horses have a two-part digestive tract. The foregut is the forward half of the horse’s digestive tract. This is the stomach and the small intestine. The front half does the easy stuff and the simple foods are absorbed in the front small intestine, and the tough stuff passes through the cecum, to the hindgut, which is the large colon, then the other small colon. You humans don’t have one of those.” 

“Really? Two digestive tracts in one animal? Sometimes I think little Abby has two digestive tracts the way she goes through diapers. So is that why horses are so long? “ 

“Perhaps so, Sam. Grazing animals like horses need a lot more water than other animals to digest their food. 

Older horses have it the worst in the winter. When they are eating the drier hay in winter, their drinking water will also be colder, and older horses have sensitive teeth that don’t like cold water. They may dehydrate, and not be able to digest the hay, and they can get very sick. Older horses need warm water in cold weather. Anyway, get ready for a slow ride.” 

“How could we be put to work in a horse?” Sam wondered out loud. 

Dorp answered, “In much the same way as in your human body. We are being eaten; no doubt about that. When we reach the intestines, we will either stay with the raw food mass, to act as a conditioner and lubricant, or we could be absorbed by the intestine and help hydrate the body. We may wind up as saliva and actually go through the foregut of the horse twice. 

I was once saliva in the same gazelle three times before being turned into ear wax. We might become blood; we might be water in muscle or organ cells. Eventually then, we would be recycled out of body through the end of the digestive tract or the urinary tract. We could also leave the body as sweat or tears or be exhaled as vapor out of the lungs.” 

“There are a lot of jobs for water in a horse, “Sam said thoughtfully. “I would prefer to leave as breath vapor. 

That sounds a lot less icky. 

“Wishful thinking, Sam. Water molecules have no choice of where we go or what job we do.” 

Sam could tell they were deep inside the horse. Time in the stomach went slow but he and Dorp talked a lot. 

“I wish I could see what is going on now.” Sam said, being squished and rolled around in the horse’s stomach.

“Very well; you now have night-vision.” 

Sam looked around and thought that the inside of a horse’s stomach does not look particularly cool. It was cluttered and drippy and oozy and moving all the time. It looked kind of like his room, except his room wasn’t this wet and his walls didn’t move. He was glad he didn’t have a sense of taste or smell right then. 

Sam asked, “Why don’t I get hungry? I should be hungry by now.” 

“You are water, Dorp replied. “You have no nutritional needs, so you have no stomach; therefore, you cannot feel hunger.” 

Sam sighed. “What a happy life water has. Wait; I have a joke. Why do cowboys ride their horses?” 

“I don’t know, Sam. Why do cowboys ride their horses?” 

“Because horses are too heavy to carry.” 

“Sam, we’re moving through the digestive track, past the small intestine. We now have a 50/50 chance of becoming manure.” 

“Oh great! That’s exactly how I wanted to spend my summer; being a pile of horse poop! This is not my idea of high adventure, you know?” 

“Really, Sam? Since you’ve left home, you’ve of become a molecule of water, slid down the side of an airplane traveling over 500 miles per hour; fallen over five miles without a parachute. You’ve been sucked up into a dandelion; then eaten by a horse and have seen more about horse digestion than the average veterinarian; and already you’re bored?” 

Sam defended himself, “I didn’t say I was bored. I just can’t make any decisions for myself anymore. I didn’t realize how many choices I could make when I was a boy. I thought everyone else controlled my life. Wow, water has no say in anything.” 

“You’re right, Sam. You don’t have control on a roller coaster either, but you decide to enjoy the ride. We’re passing through the large colon now. We have been absorbed into a bit of indigestible hay stalk, so I suspect we are going to pass through the horse without being absorbed.” 

“Did you know all along we were going to be pooped out and you didn’t tell me? Really?” 

“Sam, first of all, I didn’t know exactly where we were going to go, though I did tell you that a horse produces 10 gallon of saliva a day and doesn’t spit. Figure that one out, Galileo. Besides, you don’t seem to do too well when you know what is going to happen before hand, so I’ve decided to let you be surprised. You’ve survived everything but stagnation. 

You’ll be fine. Just relax and enjoy the trip.” 

“Sure... Enjoy being horse poop. Oh, I can see the first week of seventh grade. The English teacher will have us write a report on how we spent our summer vacations. My report will say that I spent the better part of the summer in a pile of decomposing horse manure in a pasture in western Nevada. 

To which, Miss Miflin will glibly say to me, ‘You know Sam, I think it’s time you met Mr. West; the new school principal.’” 

“Sam, Dorp sighed, “You will spend your summer with your family, and as their boy. You will not have to spend your summer vacation in a pile of manure.” 

“Thank you, Mr. Dorp. Oh no! I think I see the light at the end of the tunnel, as dad would say.” 

“That is a cleverly turned phrase, Sam. Shakespeare would say, ‘what light through yonder window breaks.’ 

Next stop: the pasture.” 

I won’t detail this step of Sam’s journey, but you can guess. They left the digestive track and piled up on the ground. 

Very often, where there is dung, there will be yellow dung flies. That evening, yellow dung flies descended on the pile to mate and the females laid eggs on the upper surface of the pile. The warmer the dung, the faster the eggs hatch. The eggs hatched a couple of days later and the larvae burrowed into the moist dung for food and warmth. It was a half inch into one curd of the dung that larvae ate a bit of dung that contained our Dorp. 

Sam asked, “What just ate us?” 

“The larvae of a Yellow Dung Fly,” Dorp answered. “They live in the dung for about two weeks, where they will pupate three times before becoming adults, and will then crawl out of the dung to live out a six-week life span.” 

 What does ‘pupate’ mean, Mr. Dorp?” 

“While human children grow gradually; moment-by-moment and cell-by-cell, winged insects grow by pupation. This means they grow a certain amount in easily seen stages. Perhaps the most famous act of pupation is when a caterpillar spins a cocoon around itself, then emerges as a butterfly. Less attractive creatures, like dung flies do the same.” 

Sam reflected for a moment then said, “That’s kind of a neat life; like being born in a room full of pizza. Pupating three times in two weeks and coming out as an adult. I wish I could grow up that fast. Maybe they just grow fast to get out of the poop. Y’think?” 

Time went by, and their host larvae grew and pupated as it was supposed to. Finally, came the day for the final pupation into an adult dung fly. Dorp and Sam were in a cell just behind the left front leg. The young yellow dung fly, a female, crawled out of the pile of dung to begin her adult life. She shook her wings off, ready to fly. Suddenly a field mouse came up and ate her. Dorp and Sam went into the stomach of the mouse. 

“Whoa!” Sam yelled. “What happened? I didn’t know mice ate insects."

“Yes, Sam, a lot of creatures in the food web eat insects. You just learned something new about the food web, eh?” 

“I guess so. What’s next? Are we going to be eaten by a fox, an owl, or what?” 

“Very few mice die of old age,” said Dorp. “An attack by either of those predators is possible, along with snakes and cats. Housecats kill an estimated 2 billion small birds and animals per year, including wild songs birds. But field mice reproduce quickly and provide a lot of food for the food web. Field mice are the main ingredient on many predators’ menu. I’m hoping it will be eaten by an owl so you can see what it is like to be in an egg.” 

Dorp and Sam made their way through the mouse’s digestive tract and found themselves as moisture in the mouse’s fur. 

I said I know how Jonah felt, in the belly of that big whale
And just like my man Jonah, that belly has a tale.”

“I’ve seen the inside of more critters, than anyone I know
I said I’ve seen the inside of more critters, than most anyone I know
I wonder if this is my payback, for shinin' so many bones, yea.” 

“Most every day, I spend time inside
a critter big enough to eat me, even one that I could ride
I’m so tired of being eaten, It really gets under my hide.” 

"Gets under my hide, get it? – ‘under my hide?’” 

“I get it Sam. Clever song. You may be able to cut an album by the time you get home.” 

"An album?"  Sam asked.

As the owl digested its meal, the mouse underwent several changes. In the bird’s gizzard, the mouse’s fur and bones were separated from its digestible parts. Those digestible parts continued through the owl, while the leftovers stayed up above and were compacted into an elliptical object called an owl pellet, which the owl regurgitated a few hours after the meal. 

This is not the kind of vomiting that humans do when they have the flu. The owl’s upper digestive tract acts as a two-way street to intake food like mice, and then, to expel the indigestible parts of the creature. Sam and Dorp left the owl through the same orifice they entered. The owl pellet landed on the ground and when they evaporated out of the pellet, they were caught up by a breeze and moved toward the east across Nevada.

Photo: rickgorehorsemanship.com

dorpwet.com