mam food and feeding

what features can be used to predict function

• shape of lower jaw

• location and shape of the mandibular fossa

• orientation + size of masticatory muscles

• dentition type

insectivores

• primitive/basal condition of eutherian mams

• wide diversity

• aerial aquatic and terrestrial

• many = incisors procumbent

• sharply cusped to no teeth

• min amount of fiber = affects digestive tract morphology

insectivore gut

no cecum, short + simple intestine

insectivore adaptations

long tongue, venomous saliva, large salivary glands

carnivory

• arboreal terrestrial marine

• sharp cutting teeth some with homodont dentition

• specialties= sanguinivorous (blood eating) piscivorous (fish eating)

carnivore gut

• short intestine and colon

• small cecum

  • most part simple

herbivory 

• browsers and grazers

  • hooved mams + aquatic grazers

• gnawing mams

  • rodents + lagomorphs

  • coprophagy (hindgut fermenter consumption of cecotropes)

*symbiotic associations + mods of digestive tract

herbivore gut

• large cecum

• large stomach

herbivore adaptations

• selenodont dentition (ruminantia)

• canines reduced or absent

• broad molars for crushing shredding grinding

• fermentation

fermentation in herbivores

• by symbiotic associations with microorganisms

• hindgut (after small intestine: perissodactyla) = non ruminating

• foregut (before small intestine: artiodactyla) = ruminating

cecum

• intraperitoneal pouch btwn small and large intestine

• enlarged in herbivores

• reduced/absent in carnivores

hindgut fermentation (perissodactyla non ruminants)

• not as high efficiency of nutrient extraction

• microorganisms in cecum, cant absorb

• toxins absorbed in blood liver must detoxify

• faster time for processing

• can work with low quality but abundant food

• 2x what’s ruminants eat

foregut fermentation (artiodactyla ruminant)

• very high efficiency of nutrient extraction (microorganisms break down material before in reaches small intestine)

• microorgs nutrients are absorbed

• microorgs can detoxify alkaloids in rumen

• slower time for processing

• benefits from high quality but limited food

• don’t eat as much volume 

types of herbivores

• folivory leaf eaters

• frugivory fruit eaters

• nectarivory nectar eaters

• gummivory gum eating

• mycophagy fungus eating

• granivory seed eating

omnivory

• everything eater

• versatile dentition

optimal foraging strategies

• decisions used by animals to obtain optimal cost benefit for foraging

• consider amount of energy to spend and amount of time to spend

marginal value theorem 

• details of when an animal will decide to leave a food patch

• energy spent moving between patches

• when is it more productive to move on

net of energy intake = energy from food - (search energy+pursuit energy+handling energy+eating energy)/search time+pursuit time+handling time+eating time

ex of food caching

• rodents

• pikas

• carnivores

• 1 marsupial

• 7 spp shrew

musculature for feeding

• temporalis

• masseter

• digastric

• pterygoid

carnivore example musculature

• large temporalis

• coronoid process large

• moderate masseter

• articulation of law nearly in line with tooth row

  • carnassial teeth large

herbivore example musculature

• small temporalis

• coronoid process absent

• masseter large

• articulation of jaw high above tooth row