A Comparison of Mammalian Alimentary Systems
Obtaining and transporting nutrients is a vital function for all multicellular organisms and different
species have evolved some interesting ways of gaining, storing and digesting their nutrients.
Hindgut fermenters
Amongst herbivores, for example, almost
all have cellulose digesting bacteria
within their gut that live symbiotically,
assisting with the break down of
vegetation. Some are classified as
“hindgut fermenters”, which have
microbes and fermentation in their
hindgut, the caecum and proximal
colon. These animals are less effecient at
digesting their food and can sometimes
be observed practising coprophagy
(eating faeces).
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Horses
Koalas
Foregut fermenters
Other herbivores are “foregut
fermenters”, or ruminants, which have
pouches with microbes in the stomach.
These microbes consume glucose from
cellulose but produce fatty acids that the
animal can use for energy. Microbes can
also be digested further along the
digestive tract as they are also a source
of protein. Foregut fermentation, or
rumination, is a slower digestive process,
but has the advantage of providing more
nutrients and wasting less energy.
Foregut fermenters include:


Cattle
Kangaroos and Wallabies
Ruminants digest plant-based food by initially softening it
within the animal's first compartment of the stomach,
principally through bacterial actions, then regurgitating the
semi-digested mass, now known as cud, and chewing it
again. The process of rechewing the cud to further break
down plant matter and stimulate digestion is called
"ruminating".
Good information about different types of digestive systems from a UK Veterinary site,
Comparative Digestion. http://vetsci.co.uk/2010/05/14/comparative-digestion/#
Pig
Describe the diet of pigs. Are they herbivores, carnivores or omnivores? Are they foregut or hindgut
fermenters?
Sheep
Describe the diet of sheep and how they feed. Are they
herbivores, carnivores or omnivores? Are they foregut or
hindgut fermenters?
Koala
Describe the diet of Koalas and how they
feed. Are they herbivores, carnivores or
omnivores? Are they foregut or hindgut
fermenters?
Dog
Describe the diet of dogs and how they feed. Are they herbivores, carnivores or omnivores? What is the
major differences between a canine alimentary tract and a herbivore alimentary tract.
In what part of the alimentary tract does most of the digestion occur?
Vampire Bat
http://www.batsnorthwest.org/BNWFall07.pdf
Describe the diet of vampire bats and how they feed. What provides most of the volume of their food ?
What provides the majority of their nutrients . Where is this digested?
Humans
Label each part of the human alimentary tract indicating the function of each .