Overview
Digestion is defined as the process in which food is broken down by both mechanical and chemical digestion. It is a process necessary for both humans and animals, as it allows important nutrients to be broken down into molecules small enough to be diffused into cells. In the human digestion (and the digestion of many other animals), food passes through the mouth, esophagus and stomach. In each organ, the food is ground and mash and chemically digested by enzymes. In the small intestine, nutrients inside the food are often diffused into the villi, and are absorbed into the bloodstream. Via the circulatory system, these nutrients are dispersed throughout the body to be ultimately used as energy for the human body. The digestion of starch, a carbohydrate, is an example of the importance and necessity of digestion. When consumed, glucose is often in the form of starch, a long chain of glucose monomers. Being so sizable, the starch is unable to be diffused into cells, losing any nutritional value it might have for the human body. Amylase though and other forms of mechanical and chemical digestion break down the starch into glucose molecules. After having been broken down into smaller glucose molecules, the starch diffuses into the villi of the small intestine and passes into the bloodstream. It is then circulated throughout the body to be used for cellular respiration (Glucose + Oxygen --> Carbon Dioxide + Water + ATP). A process which occurs in the mitochondria of all cells and produces ATP, a key source of energy for the human body.
The Tree Pangolin Diet
Tree Pangolins are carnivores (insectivores) and secondary or tertiary consumers. While the majority of Tree Pangolins eat ground termites, ants and tree termites, Tree Pangolins have also been known to eat bee larvae and other invertebrates (flies, worms, earthworms, and crickets) [1]. On average, a grown Tree Pangolin will consume 140 to 200 grams of insects per day [2]. The Tree Pangolin’s singular diet though provides a complication for its captivators, who struggle to feed the Tree pangolin. The main reason that Tree Pangolin’s are uncommonly found in Zoo’s [3].
Ground Termites
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Ants
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Tree Termites
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Obtaining Food
To obtain food, the Tree Pangolin must first locate an ant or termite colony. They do so using mainly their sense of smell and hearing as Tree Pangolins, being nocturnal creatures, have very poor eyesight [4]. Then, using the large and curved claws found on their forefeet, Tree Pangolins excavate anthills and termite mounds and tear apart termite tree nests in order to expose their food source [5]. After unearthing their prey, the Tree Pangolin’s tongue, a ten to twenty-seven inch organ stored in the Pangolin’s chest cavity will flick out, catching termites and ants [6]. The length (around 40 cm) and width (6.0 cm) of the Tree Pangolins tongue make this task highly more effective and easier, as being both long and skinny, a Pangolin’s tongue can dart through the passageways built in termite and ant mounds [7]. Likewise, a gland located in the Pangolin’s chest lubricates the Tree Pangolin’s tongue with a sticky saliva, which allows the Tree Pangolin to capture a greater number of prey [8].
The Digestive Anatomy
As the Tree Pangolin has no teeth, the Pangolin’s stomach is especially adapted to increase the mechanical digestion of food. The Pangolin’s stomach, an organ very similar to the bird’s gizzard (the reason for the diagram of the bird’s digestive tract) contains pebbles, dirt and sand to help grind and mash food [9]. Likewise, extruding from the interior of the Pangolin’ stomach are keratinous spines, which further aid in the mechanical digestion of food [10]. To chemically digest food, bile acid is produced in the Pangolin’s liver to break down the fats found in the Pangolin’s diet [11]. Formic acid or methanol acid is another enzyme found in the Tree Pangolin’s stomach. Surprisingly, this acid comes from the ants found in the Tree Pangolin's diet, and is an acid imperative to the digestion system of the Pangolin [12]. Other then these differences though, the Pangolin’s stomach is similar to that of the human, as both are muscular organs, of which the interior is covered with a mucus coating.
This is an image of a birds digestive tract. Even though birds and Pangolins are in different classes, they share a very similar digestive system. In fact, the key part of the pangolin's digestion system, its stomach, serves an almost identical purpose to that of the bird's gizzard, to grind and mash food. |