Hippo (Hippopotamus amphibius)
Introduction:
The hippo is a large semi-aquatic mammal that is found wallowing in the rivers and lakes across sub-Saharan Africa. Hippos's ears, eyes and nostrils are on top of the head, which means that when the Hippopotamus's body is immersed in the water, they are still able to see, hear and breath whilst keeping cool in the hot sun. They love water so much, and that is why the Greeks gave them the name of "river horse". The lifestyle of hippos is nocturnal and they tend live in a herd containing 20 to 100 individuals. During daytime, this mammal prefers to sleep in shallow water, grouped closely together. Mating and childbirth occur in these water. [1]
Hippos usually weigh between 2,200lbs - 9,900lbs, and their body varies from 6.5 ft to 16.5 ft, held by short and stocky legs. Common skin colors are grey, brown and black, but pink hippos are found as well. The Hippopotamus can move fast up to 30 mph on land. [2]
The Hippopotamus has a gestation period of 240 days and their long life span is around 40 - 50 years. Calves are fully weaned by the time they are 18 months old but tend to remain with their mother until they are fully grown, often not leaving her until they are 7 or 8 years old. [2]
The Hippo is an Herbivore
Different types of grasses are the main source of food for the Hippopotamus that are found growing on plains relatively close to water. [1]
The hippo is a large semi-aquatic mammal that is found wallowing in the rivers and lakes across sub-Saharan Africa. Hippos's ears, eyes and nostrils are on top of the head, which means that when the Hippopotamus's body is immersed in the water, they are still able to see, hear and breath whilst keeping cool in the hot sun. They love water so much, and that is why the Greeks gave them the name of "river horse". The lifestyle of hippos is nocturnal and they tend live in a herd containing 20 to 100 individuals. During daytime, this mammal prefers to sleep in shallow water, grouped closely together. Mating and childbirth occur in these water. [1]
Hippos usually weigh between 2,200lbs - 9,900lbs, and their body varies from 6.5 ft to 16.5 ft, held by short and stocky legs. Common skin colors are grey, brown and black, but pink hippos are found as well. The Hippopotamus can move fast up to 30 mph on land. [2]
The Hippopotamus has a gestation period of 240 days and their long life span is around 40 - 50 years. Calves are fully weaned by the time they are 18 months old but tend to remain with their mother until they are fully grown, often not leaving her until they are 7 or 8 years old. [2]
The Hippo is an Herbivore
Different types of grasses are the main source of food for the Hippopotamus that are found growing on plains relatively close to water. [1]
Ruminant Digestion
Ruminants have a unique digestive system that allows them to better abtain and use energy from plant-based foods than other herbivores. In a reminant digestion,
60-75% of ingesta (known as cud) is fermenated by microbes in a specialized stomach before exposed to gastric juices. The stomach has a complex structure with four compartments, named the rumen, reticulum, omasum, and abomasum.
Anatomy and Physiology
Anatomy of the ruminant digestive system includes the mouse, esophagus, four -compartment stomach, pancreas, gall bladder, small insteine, and large intestine.
[3] Hippos do not have a caecum.
Mouth - Where food is chewed and mixed with saliva; there's no enzymes in saliva
Esophagus - No sphincter valve, therefore opens into reticulum and rumen; muscle contractions move in both directions
Reticulum - Located next to the heart; has a honeycomb appearance that helps collect smaller digesta particles and moves them into the omasum while the larger particles remain in the rumen for further digestion; no enzymes secreted
Rumen - The largest stomach compartment lined with papillae for nutrient absorption and divided by muscular pillars into sacs; act as a fermentation vat by providing an anaerobic environment
Omasum - A spherical shape connected to reticulum; known as "manyplies" because it contains folds or leaves or tissue; those folds reduce the particle size and increase the surface area, which further increase the water absoption; no enzymes secreted from walls
Abomasum - "True stomach" that is most similar to a stomach in a non-ruminant; secrets HCl to kill bacterias and balance the pH; secrets pepsin that break down large protein molecules, and receives digestive enzymes like pancreatic lipase; secrets mucous to protect the cell wall from acid damage
Small intestine - Where carbohydrates, proteins and fat are emulsified by enzymes and absorbed
Large intestine - Absorbs water passing through it and excrete the remaining material as feces
Ruminants have a unique digestive system that allows them to better abtain and use energy from plant-based foods than other herbivores. In a reminant digestion,
60-75% of ingesta (known as cud) is fermenated by microbes in a specialized stomach before exposed to gastric juices. The stomach has a complex structure with four compartments, named the rumen, reticulum, omasum, and abomasum.
Anatomy and Physiology
Anatomy of the ruminant digestive system includes the mouse, esophagus, four -compartment stomach, pancreas, gall bladder, small insteine, and large intestine.
[3] Hippos do not have a caecum.
Mouth - Where food is chewed and mixed with saliva; there's no enzymes in saliva
Esophagus - No sphincter valve, therefore opens into reticulum and rumen; muscle contractions move in both directions
Reticulum - Located next to the heart; has a honeycomb appearance that helps collect smaller digesta particles and moves them into the omasum while the larger particles remain in the rumen for further digestion; no enzymes secreted
Rumen - The largest stomach compartment lined with papillae for nutrient absorption and divided by muscular pillars into sacs; act as a fermentation vat by providing an anaerobic environment
Omasum - A spherical shape connected to reticulum; known as "manyplies" because it contains folds or leaves or tissue; those folds reduce the particle size and increase the surface area, which further increase the water absoption; no enzymes secreted from walls
Abomasum - "True stomach" that is most similar to a stomach in a non-ruminant; secrets HCl to kill bacterias and balance the pH; secrets pepsin that break down large protein molecules, and receives digestive enzymes like pancreatic lipase; secrets mucous to protect the cell wall from acid damage
Small intestine - Where carbohydrates, proteins and fat are emulsified by enzymes and absorbed
Large intestine - Absorbs water passing through it and excrete the remaining material as feces
The Hippo Has a Ruminant-like Digestion
The purpose of chewing the cud is to break food into small particles that are easier to be digested and absorbed in the gut. Since the plant matter most ruminants eat is hard to digest, ruminants have to regurgitate these leaves and grasses again and again. Hippos do not ruminate but enjoy the advantages of rumination. They do not use their teeth to chew their meals; they tear and soften the grasses instead. The three-chambered stomach suggests hippos have a reminant-like digestion, which makes hippo a "pseudo-ruminant".The hippo's stomach consists of the parietal blind sac, forestomach (the connecting chamber), and glandular stomach (the main stomach). [4] Food is ground up into a soup in the forestomach. HCl, pepsin and other enzymes are secreted in the glandular stomach for digestion.
The purpose of chewing the cud is to break food into small particles that are easier to be digested and absorbed in the gut. Since the plant matter most ruminants eat is hard to digest, ruminants have to regurgitate these leaves and grasses again and again. Hippos do not ruminate but enjoy the advantages of rumination. They do not use their teeth to chew their meals; they tear and soften the grasses instead. The three-chambered stomach suggests hippos have a reminant-like digestion, which makes hippo a "pseudo-ruminant".The hippo's stomach consists of the parietal blind sac, forestomach (the connecting chamber), and glandular stomach (the main stomach). [4] Food is ground up into a soup in the forestomach. HCl, pepsin and other enzymes are secreted in the glandular stomach for digestion.
Challenges
The major threat of hippos is illegal and unregulated hunting for meat and ivory. In addition, hippo habitats have greatly diminished over past 200 years because of the increasingly human activity and polluted fresh water. [5] These two factors directly cause the dramatic decrease in the number of hippos. Therefore, more completed conservation actions should be taken. For example, a more rigorous law is required to enhance the citizen's awareness of protecting hippo and their habitats. Of course, there should be much harsher punishments if someone is caught hunting hippos illegally.
The major threat of hippos is illegal and unregulated hunting for meat and ivory. In addition, hippo habitats have greatly diminished over past 200 years because of the increasingly human activity and polluted fresh water. [5] These two factors directly cause the dramatic decrease in the number of hippos. Therefore, more completed conservation actions should be taken. For example, a more rigorous law is required to enhance the citizen's awareness of protecting hippo and their habitats. Of course, there should be much harsher punishments if someone is caught hunting hippos illegally.
References
[1]http://animaldiversity.ummz.umich.edu/accounts/Hippopotamus_amphibius/
[2]http://a-z-animals.com/animals/hippo/
[3]http://faculty.fortlewis.edu/LASHELL_B/Nutr2-Rumdigestion.pdf
[4]Robertson M, Persson F, Vicente B, Fogler H.S. "Modeling the Digestive System of a Hippopotamus" University of Michigan
[5]http://www.iucnredlist.org/details/10103/0