Prehensile upper lip for browsing
Consumes bushes and shrubs in forest
Mastication
Physical reduction of feed Especially important in non-ruminant
herbivores
Herbivores must chew continuously (4050,000 times a day) to increase surface area
Prehension
Seizing and conveying feed to mouth
Mechanisms vary with behavior and diet Forelimbs
Comparative Digestive Physiology
Why Do Animals Digest?
Food not ingested in suitable state
Physical nature of food determined by:
gathering apparatus for uptake type of digestive system
The Importance of Prehension in Diet Formulation
White Rhino (“wijd” = wide)
Squared off upper lip used to “crop” grass
Grazes on savannah
Black Rhino
Mastication or chewing
To crush the food, increase surface area and allow enzymes to act on molecules
Carnivores only to reduce the size of the particle to a size small enough to swallow
Pigs use snout to root in ground and pointed lower lip to convey feed into mouth
Birds use beak and tongue Drinking varies as well
Most mammals use suction Dogs and cats use tongue to form ladle
Mouth
Functions
Grasp food Taste Masticate food Mix with saliva
Digestion in the Mouth
Prehension
Bringing the food to the mouth
Upper limbs, head, beak, claws, mouth, teeth and lips
Relative importance varies by species Horses
lips when eating from manger teeth when grazing
Cows and sheep have limited use of lips
Use long rough tongue to grasp forage
Synthesis - true protein, FA, starch, vitamins Excretion – elimination of waste products
Via bile (toxins, microbes etc) Via rectum (Ca, Mg, P)
Species-Dependent Nutritional Adaptations
Includes involvement of:
Teeth Jaws and jaw musculature Alimentary canal
Stomach - May be simple or become sacculated to compartmentalize functions for prolonged storage of feed and utilization of bacterial fermentation (langures and ruminants)
Primates, raccoon
Snout
Elephant, tapir
Tongue
Anteater, cow, sheep
Lips
Horse, sheep, rhinoceros
Prehension
Domestic mammals use lips, teeth and tongue
Primary Functions of the Digestive Tract
Transport food – peristaltic contractions Digestion
Mechanical breakdown Chemical breakdown
Absorption
Passive diffusion and active transport
May also become voluminous for storage of large amounts of feed (vampire bats)
Large intestine - varies substantially in length, compartmentalization, and complexity among species
Adaptations with teeth
Carnivores Herbivores Edentates (sloths, armadilloes, anteater)
Relative toothlessness
Morphological Adaptations for Herbห้องสมุดไป่ตู้vory