Food For Carnivorous and Herbivorous Vertebrates is primary For Life and Life Processes
Nutrients are more concentrated in the carnivores' diet and therefore the herbivores digestion is a longer process. However, the end consequent is the same. They both want nutrients for life and life processes.
Carnivores eat flesh, herbivores eat plant life. Both are heterotrophs, which accumulate their nutrients from organic substances and use enzymes in the breakdown of the substances to contribute chemicals that can be absorbed by the animals' cells.
The vertebrates want food for metabolism (growth, repair, movement, cell metabolism, Dna replication, vision, flight).
Food provides nutrients: carbohydrates, proteins, lipids, vitamins, minerals and water. The first three nutrients are needed in large amounts (macronutrients), vitamins and minerals are required in small amounts (micronutrients). Water is required in large quantities to aid metabolism, which occurs in an aqueous environment.
Carnivores use generally predatory methods to feed, eg, chasing, ambushing, trapping, netting, using lures and using camouflage. Predators have evolved stealth, speed, power and large jaws.
Polar bears, Ursus maritimus, use their white coat to blend into the snow of the Artic to catch unsuspecting seals. They can move quickly on ice/snow to capture the slow seals, but are no match in water against the seals' swimming pace. The Humpback whale, Megaptera novaeangliae, sifts small invertebrates and fish straight through their comb-like plates (baleen). Crocodiles and Alligators clamp their victims, drowning them, biting pieces off when required. The Humpback Angler Fish, Melanocetus johnsonii, has an appendage in the middle of its eyes that moves like a lure, to attract prey. Birds of prey, (hawks, eagles and owls) hover above their prey and swoop down to capture them unsuspectingly. Some birds of prey prefer carrion. Non-venomous constrictor snakes such as anacondas, boas and pythons crush their prey in their strong muscular coils. Venomous snakes inject a poison into their prey to anaesthetise it, before ingestion.
Herbivorous vertebrates do not rely on predation. Some fish, tortoises and lizards eat plant material and pond weed. Some herbivores supplement their diet with animal protein such as slugs, snails and worms, changing their category to an omnivore (as are most humans, apart from vegans). Some birds eat berries, seeds and buds, other larger birds eat leaves. Cattle, sheep, goats and rabbits graze on grassland.
Processing of the food starts in the mouth. Carnivores have more incisor and canine teeth than herbivores for tearing, cutting and capturing their prey. Herbivores have more molar teeth to help in the large amounts of tearing, milling and crushing complicated with base plant material. Birds have no teeth, their food is ground to fine material in their gizzards, which consist of grit or small stones ingested by the bird to break down the plant material aided by strong muscular movements of the gizzard.
Digestion of animal tissue is quicker than plant tissue and is more effective in providing the principal nutrients to the animal. Herbivores have more overall digestive systems than carnivores and digestion takes a lot longer to complete, for example, herbivores can take whatever from 30 hours to 100 hours to discharge food (horse and cow respectively of similar mass). A carnivore can take any hours.
Food is processed by Ingestion, Digestion, Absorption and Elimination.
The alimentary canal is one long tube from mouth to anus.
Carnivores' food is processed into smaller pieces by the teeth and mixed with saliva from the salivary glands, which moisten the food for easier converyance and contains enzymes which start to break down carbohydrates. The food (bolus) is conveyable down the oesophagus by peristalsis. The bolus enters the stomach and mixes with supplementary enzymes, from the stomach, pancreas and liver, which break down carbohydrates supplementary to smaller sugar molecules; proteins are broken down into smaller peptide chains. Hydrochloric acid is produced by the stomach to breakdown proteins and kills any undesirable micro-organisms. This mixture (chyme) enters the small intestine, where lipids are broken down into fatty acids and glycerol, proteins are broken down into amino acids, disaccharides are broken down into glucose. Absorption generally occurs in the small intestine. The glucose and amino acids are conveyable straight through the villi and micro-villi of the small intestine's epithelium into blood capillaries. Fatty acids and glycerol are conveyable straight through the villi and micro-villi to the lacteals, which converyance them, via the lymph system, to the blood vessels. The digested material enters the colon. The material is quite fluid, water is absorbed straight through the epithelial wall of the colon. Symbiotic, microbial activity takes place anaerobically in the colon. The bacteria faultless the digestion of any salvageable material. Some bacteria synthesise vitamins which, with any existing minerals, are absorbed by the colon into the blood system. Gas (hydrogen, carbon dioxide and methane) are produced by the bacteria, which is emitted as wind. The waste is eliminated as faeces, which is composed of fibre, dead and alive bacteria, epithelial cells from the gastrointestinal tract, fatty acids and mucus from the colon lining.
Carnivores use hindgut fermentation (fermentation of food material in colon) Herbivores use hindgut fermentation, such as rabbits and zebras, or foregut fermentation such as ruminants and kangaroos. Fish have no hindguts, but mammals, birds and terrestrial reptiles do.
The most numerous and diverse herbivorous vertebrates are ruminants which use foregut fermentation.
Some animals eg, rabbits, eat their own faeces (copography). Copography allows non-digested cellulose to re-enter the small intestine for absorption. A horse's digestive principles allows the cellulose to re-enter the small intestine by a reflux request for retrial of the digestive system. The Svalbard reindeer (Rangifer tarandus platyrhyneus) supplements its diet by eating the faeces of the barnacle goose (Branta leucopsis).
Conclusion:
Carnivorous and herbivorous vertebrates use varying methods to accumulate their food and use distinct digestive processes. However, both use the same four principles of nutrition, namely, ingestion, digestion, absorption and elimination. In the main, carnivores hunt for their food and herbivores forage.
