Food & Feeding - ZOOL 408
Are sabretooth jaws optimal for biting into large prey why or why not?
- No they are not because the jaw is not optimal for biting the vulnerable structures of large prey - They evolved for the fast and effective killing of prey
Do pandas have a thumb? What other species displays this? How did it evolve?
- No, they have a "false thumb" made of carpal bone (radial sesamoid) - This is convergent between the red and giant pandas - Probably evolved from manipulating bamboo for giant pandas and for arboreal locomotion in red pandas
Differences in pinniped dentition?
- Otariids (sea lion) --> conical teeth - Phocids (crabeater seal) --> trident-like triangular teeth
Adaptations for some terrestrial insectivores?
- Production of venomous saliva - Paralyzes prey and allows for storage (reliable energy)
Provide an example of how diet affects ecosystem dynamics and structure
- Serengeti Plains, system driven by rainfall, grass growth follows rain, migration follows - Zebra first --> pick up on high volume - Wildebeest second --> foregut fermenter - Thompson's gazelle third --> more selective feeder with a smaller digestive system (also foregut fermenter)
How does a whales heart rate change with diving?
- Surface --> tachycardia - Descent, lunge, filter, ascend --> bradycardia
Which nerve provides motor function and sensation to the larynx?
- Vagus nerve (recurrent laryngeal nerve - a branch from the vagus nerve)
Do herbivores and carnivores have a cecum?
- Yes - Herbivores have a large one with abundant bacteria, which aid in the enzymatic breakdown of plant materials - Carnivores have one that is reduced and partially or wholly replaced by the appendix
Is the giant panda a carnivore?
- Yes, it technically is in the Carnivora order - However, it eats mainly vegetation (bamboo)
Bagging
- a way of catching elephant seals
What are walrus tusks used for?
- aggressive encounters - establishing dominance hierarchies - feeding - locomotion - brekaing through ice
GI tract in herbivores
- alimentary canal is longer - stomach is simple (non-ruminant) or has many internal folds and chambers (ruminant)
Characteristics of giant anteater tongue?
- anchored to the base of the sternum - covered by submaxillary secretion - posteriorly directed barbs to trap ants
Draculin
- anticoagulant in vampire bat venom
Which microorganisms are involved in digestion?
- bacteria - protozoa - yeasts - fungi
How do mustelids kill prey?
- bite to the base of the skull - sever jugular vein
Carnassials
- bladelike, shearing cheek teeth found in most carnivores - last upper premolar and first lower molar (P4/M1) - highly developed in felids and canids
Sanguinivorous
- blood eating mammals (vampire bats) - 3 species with New World distribution
Bone crushing specializations in some species?
- bone crushing teeth (P4/P4 wolf, P3/P3 hyaena) - vaulted forehead (evolved to dissipate compressive forces during bone cracking)
Individual acoustic signatures
- breathing sounds used by vampire bats to identify prey - same way we identify humans by vocalizations
Dentition in herbivores
- broad or absent canines - molars broad for crushing, grinding and shredding of vegetation - diastema often present
Characteristics of gnawing mammals
- cannot produce cellulase --> require microorganisms - hindgut fermenters - stomach has 1-3 regions and is simpler - skulls have large incisors - often diastema present - internal or external cheek pouches in some species
Which fecal pellets are eaten?
- cecal pellets -- > moist, mucous coated and black - normal feces are hard and dry (not eaten)
Which monkey group has cheek pouches?
- cercopithecine monkeys (old world) - African
Kallikrenin
- cleaves clotting factors (fibrinogen) to prevent clotting of the blood of prey
What kind of stomach do cetaceans have?
- compartmentalized stomach --> indicative of ungulate origins possibly - 3 chambers, don't regurgitate food - enzymes released in second stomach not first
Optimal foraging theory
- consuming the most energy while expending the least amount of energy
How are the cortical and anatomical proportions related in the nose of a mole?
- cortical processing area for touch information from the star is visible in 11 separate stripes, each representing a single nasal appendage - cortical structure is massively weighted to this organ
Ventral grooves
- creases that run vertically down the underside of a whale's jaw all the way to its stomach - ex. blue whale, humpback whale
Monogastric system (hindgut fermentation)
- digestion begins with mastication and enzymatic activty from salivary enzymes (same as other one) - digestion continues in the stomach - no regurgitation - from the small intestine, the finer particles move into the cecum - fermentation by microorganisms occurs in the cecum and large intestine
What aids the star-nosed mole in finding food?
- each nostril surrounded by 11 rays of different length (22) - extremely mobile proboscis - explores water and air - have specialized muscles to move the nose disc around quickly and efficiently
What was baleen an early analogue for?
- early analogue of plastic - was used in corsets
Dugong diet and dentition
- eat aquatic vegetation much softer than their "sister" family
Manatee diet and dentition
- eat tougher water hyacinth, mangrove leaves
Coprophagy
- eating feces - produce two kinds of fecal pellets - digestion of cellulose in hindgut fermenters occurs in cecum - no regurgitation and rapid food passage - minimal digestion of plant fibre
Nectivore adaptations
- elongated snouts - weak teeth - reduced number of teeth - poorly developed jaw - long tongue that is slender and has a brush like tip (can extend to 150% of body length)
What is microwear?
- etching in the enamel of teeth - based on how big your prey is you get different scratching patterns
Omnivores
- everything eating - versatile dentition - opossums, pigs, bears, racoons, skunks, etc.
Lunge feeding
- facilitated by extensible ventral groove blubber (throat grooves) - muscle action controls the flux of water into the mouth - collects massive amounts of krill and water into mouth - ex. fin whale
Frugivore
- feed mainly on fruit - ex. some bat species (pteropodids, phyllostomids), phalangerids, tupaiids, primates
Folivore
- feed mainly on leaves - difficult to digest and nutritionally poor - lots of leaves have toxic compounds (phenolics and terpines) - ex. koalas
Granivore
- feed mainly on seeds - also often eat fruits and nuts - can have a strong influence on plant recruitment
Nectivore (which groups?)
- feed on nectar - six bat genera, marsupial honey possums
Myrmecophagous
- feeding primarily on colonial insects such as ants and termites - represented by many families (ex. armadillos, pangolins, aardvark)
Rugae
- folds of the interior lining of the stomach
Variables in foraging
- foods (quantity vs quality, nutrient requirements, large vs small prey, handling time) - how to locate food (search strategy) - vigilance (time spent on kids) - sex, age, reproductive status - evolutionary constraints
Is hindgut or foregut more efficient?
- foregut because microorganism digestion starts sooner - hindgut fermenters must detoxify alkaloids in liver (require blood stream transport), cannot digest cellulose as efficiently
Foregut vs hindgut fermentation
- foregut fermenters have slower passage of food - hindgut fermentation is efficient if high protein - hindgut fermenters must eat large volumes of food
Ruminant herbivore
- four-chambered stomach, large rumen - long intestines (both small and large) - ex. artiodactyls (giraffids, antilocaprids, cervids, bovids)
Baleen
- fringed plates of keratinized material that hang from the upper jaw - found in mysticete whales - grows throughout life
Mycophages
- fungus eating - fungi contain 70-90% water, protein, vitamins and minerals - scurids, murids, marsupials, primates
Guild
- group of species having similar ecological resource requirements and foraging strategies - ultimately have similar roles in the community
Food hoarding (caching)
- handling of food for the purpose of conserving it for future use - avoids food shortages - reduces predation risk - pretty much anything can be cached - marsupial pygmy opossums, shrews, moles, monkeys, foxes, wolves, weasels, mink, hyenas, tigers, rodents, pika
Pseudoruminants
- have "3 stomachs" rather than 4 - do not "chew the cud" - ex. Camelids, hippopotamidae (because omasum is tubular and almost indistinct)
How diet relates to metabolic activity in three-toed sloths
- have a bad diet --> low mass of digesta in gut - travel only 24m/day (average) - low basal metabolic rates - have low body temperature
What can telemetry tell us about aquatic mammals?
- heart rate - dive patterns - time depth recordings
Pit organ
- in the nose of common vampire bats - are sensitive to infrared radiation that is emitted by blood-rich skin surfaces of prey
Constraints on bears consuming wild fruits for fall energy accumulation?
- intake rate - physiological capacity of the GI tract - metabolic efficiency of gain in body mass
Realized niche
- interactions with other species results in a narrower niche
Diet of Odobenids?
- largely clams but will eat other invertebrates - sometimes seals - can eat up to 6000 clams per feeding session
What is the benefit to killing your prey faster?
- less competition and more time to feed
Why is sloth metabolic rate so low?
- low muscle mass in folivores - leaves have low available caloric density - toxic substances in leaves --> low BMR may reduce absorption of these
Gumivores
- main food source comes from the exudate of trees - includes sap, resins, or gum - marmosets, strepsirrhini primates (lemurs, galagos, pottos), gliders - often not only obtaining nutrients from this
Insectivory
- mammals that consume insects arthropods, or worms - likely the primitive condition of eutherian mammals based on dentition
Thylacosmilus atrox
- marsupial sabre-tooth from South America - had a special jaw component dedicated to tooth protection
Which muscle is well developed in herbivores and why?
- masseter muscle - for grinding food
Elephant seal dive duration and depth
- max 80-90 minutes - max 1567-1581 m
Sanguinivorous adaptations
- modified rostrum with larger incisors and canines - small cheek teeth - tongue with grooves at border (like straws) - stomach is long, tubular and highly distensible - small intestine is thin - kidneys modified
What is a source of mortality in elephants?
- molar wear - it is a sign of inefficient food processing
Characteristics of Odobenids?
- monotypic - sexually dimorphic - blubber can be 15 cm thick - tusks in males and females are enlarged canines - tusks lack enamel - similar to otariids
Who do three-toed tree sloths have a mutualistic relationship with?
- moths eat from the feces of sloths and then live on their backs and deposit nutrients for algae growth in their fur - the sloths can eat the algae (highly digestible and lipid rich)
Hutchinsonian niche
- n-dimensional hypervolume where the dimensions are environmental conditions and resources - define the requirements of an individual or species to practice its way of life and for its population to exist - ex. temperature, diet, moisture
Mesial drift
- natural movement of teeth over time toward midline of the oral cavity - seen in elephants, silvery mole rat, manatees, wallabies - convergent dentition
Characteristics of Colobus monkeys?
- no cheek pouches - sacculated stomachs (pouches in stomach for housing bacteria) - large salivary glands - most are folivores - primarily arboreal
Do carnivores only eat meat?
- no they do not, some can be herbivorous, some can be omnivorous, etc.
Do ruminant artiodactyls have upper incisors?
- no, they have a callous pad on the upper gum - less wear on teeth
Diet of the sloth bear? Adaptations to diet?
- omnivorous - termites, bees, honey, fruit, leaves - have a long tongue, and missing upper incisors which makes eating insects easier
Common vampire bat
- only mammal that feed exclusively on blood - only feeds on a single animal on any 1 night - meal lasts 10-60 minutes - excrete most water quickly
How do canids hunt?
- opportunistic hunters - rely on social intelligence, social organization, and behavioural adaptations - solitary and pack living
Where does the recurrent laryngeal nerve originate, and what is it a branch of?
- originates from the spinal cord in the neck - branch of the vagus nerve
Aphotic zone
- permanently dark layer of the oceans below the photic zone - sunlight does not penetrate at all
Herbivorous
- plant eating mammals that consume green plants - are at the base of the consumer food web
Diet related differences in skull morphology of bears?
- polar bears have a much lower bite force and display greater stressors on their skull under the same amount of force (weaker and less work efficient, cannot deal with large loads) - polar bears eat mainly fats which don't require a strong bite
Folivore adaptations?
- powerful jaw - small stomach - greatly enlarged cecum (lots of microbial fermentation) - toxic compounds inactivated in liver - some don't drink free water so they rely on water from vegetation
Graminivore
- primary diet consists of grasses
Masting
- production of an overabundance of seed to ensure species survival
Holling's Type II functional response
- rate of prey consumption by a predator rises as prey density increases - eventually levels off at a plateau (or asymptote) at which the rate of consumption remains constant regardless of increases in prey density
Which members of Carnivora are folivores?
- red panda - giant panda
Common adaptations in myrmecophages? (7)
- reduction or absence of teeth - teeth often peg-like - long, extensible tongues - elongated snouts - strong front feet - large claws - enlarged salivary glands
Marginal value theorem
- related to giving up density - theorem that predicts when animals will stay or leave
What do carnivorous bats feed on?
- rodents - birds - frogs - lizards - fish - bats
What are the two main groups of herbivores and how do they differ?
1. Browsers and grazers - browsers feed primarily on stems, twigs, buds and leaves - grazers feed primarily on grasses and forbs (emerging vegetation still attached to the ground) - horses, moose 2. Gnawers - rodents and lagomorphs
What are the two bite hypotheses for Smilodon?
1. Canine Shear-Bite - stay low to ground and bite in 2. Can-opener Model - get down and bite and then stand up using body mass to puncture
What are the 7 orders that are insectivorous?
1. Monotremata (echidnas, platypus) 2. Insectivora (hedgehogs, shrews, moles) 3. Chiroptera (bats) 4.Xenarthra (anteaters, armadillos) 5. Pholidota (pangolins) 6. Tubulidentata (aardvarks) 7. Carnivora (aardwolves)
What are four ways echolocating bats can be divided into guilds?
1. Preferred habitat 2. Foraging behaviour 3. Distinct adaptations in wing morphology 4. Structure of echolocation signals
What are the four parts of a ruminant stomach?
1. Rumen 2. Reticulum 3. Omasum 4. Abomasum --> true or glandular stomach (similar to monograstrics)
Clouded leopard size
60-110 cm 11-25 kg Quite large canines
What species eats coffee berries and excretes coffee beans?
Asian palm civet
What is a cecum?
Blind pouch at the juncture of the large intestine
Which species has the largest gape of any extant carnivore? Why?
Clouded leopards - If you have huge canines, you need to be able to open up your mouth enough to use them
How does microwear tell us about extinct and extant species?
It allows us to extrapolate things like size and diet of extinct species by placing it on a graph with known extant species according to the microwear
Do insectivores have a cecum?
No
Is size of baleen related to body size?
No it is not, and the size and shape are quite variable
At what latitudes are bats insectivorous?
North of 38N South of 40S
N-dimensional hypervolume
The hypothetical space that a species occupies according to a set of 'n' variables, or niche dimensions
Do social hunters have a weaker or stronger bite force than solitary hunters?
They have a weaker bite force at the canines
Euphotic zone
Upper layer of a body of water through which sunlight can penetrate and support photosynthesis
How does niche differentiation of sympatric congeneric bat species occur?
Use different frequencies for echolocation which alters their ability to reduce clutter and distance determination (results in different prey)
Do all mysticetes live in salt water?
Yes, they all live in salt water
What are three ways to build a paleo-reconstruction
1. Body mass-prey size relationship 2. Morphology and bite patterns 3. Tooth wear patterns (microwear and breakage)
Thylacoleonidae
- "marsupial lion" - bite force quotient is about the same as an African lion twice its size - indicates it filled a large-prey hunting niche
Carnivorous
- "meat eating" mammals - includes order Carnivora (canids, mustelids, felids, ursids) - marsupial dasyurids (marsupial mice, native cats, Tasmanian devil)
Paraxonic
- 3rd and 4th digits bear weight - seen in Artiodactyla
Diet and adaptations of the dusky leaf monkey
- 58% leaves and 42% fruit - high capacity stomach - microbial action in stomach for detoxification - prolonged retention in stomach and haustrated colon - foregut/hindgut fermentation combo
Diet and feeding of proboscis monkey
- 66% leaves and 26% fruits (mainly unripe) - foregut fermentation
Dasyuridae
- 69 species - largest is 9 kg - scavenger and predator (reptiles, amphibians, birds, small mammals) - strongest bite force relative to size
Example of cryptic speciation?
- Clouded leopards from Borneo and Sumatra vs those in Southeast Asian mainland
Which aquatic animals are carnivores?
- Mysticete cetaceans - Odontocete cetaceans - Seals (phocids) - Sea lions (otariids)
Rumination steps (foregut fermentation)
- rumen --> largest chamber where food is moistened, kneaded and mixed with microorganisms - material moves to reticulum (a blind sac) where a "cud" is formed - the cud is regurgitated and re-chewed by the animal - fermentation releases fatty acids that are absorbed - food is swallowed again and enters the omasum where further kneading occurs - food moves to abomasum (true stomach) and is mixed with digestive enzymes - material passes to small intestine and is absorbed
Eimer's organs
- sensitive tactile organs on the snouts of moles and desmans - allow for rapid sensory discrimination of objects
Non-ruminant herbivore
- simple stomach, large cecum - ex. lagomorphs, perissodactyls (horses, tapirs, rhinos), elephants, hyraxes, rodents
Larder hoarding
- single storage area - ex. red squirrels
Skim feeding
- skim the surface - often observed in species without throat grooves (ex. northern right whale)
Bradycardia
- slowing of the heart rate - reduces oxygen needs
Holling's disc equation
- specific amount of handling time associated with prey item that is invariant to the density of the prey - prey items are easier to find as their density increases, handling time per prey item is the same - max # of prey items eaten is determined by ratio of available searching and handling time
Scatter hoarding
- spread cache around territory - ex. arctic fox
Which muscle is well developed in most carnivores and why?
- temporalis muscle - for seizing and holding prey
Dysphotic zone
- the deeper, less biologically productive portion of the photic zone - sunlight decreases rapidly with depth - no photosynthesis
Giving up density
- the food density in a patch at which the animal will choose to leave to another patch
Fundamental niche
- the space and resources a species occupies when free from interference
Sensory ecology
- the study of how organisms acquire, process, and respond to information from their environment - important in determining the structure of animal communities
Are hyraxes ruminants or non-ruminants?
- they are not ruminants - have a large cecum and a smaller paired cecum - they are subungulates, not rodents like originally thought
How do bats catch insects?
- they can trap by mouth, wing tip, or uropatagium
Why would animals stay at a patch longer rather than switching?
- this patch is more profitable - the distance between patches increases - when the environment as a whole is less profitable
Why don't prey escape through bubble net walls?
- trumpeting calls may be intense within the bubbles due to insonification conditions but inside of net is silent
Bubble net feeding
- unique method of cooperative feeding - used by some cetaceans (ex. humpback whales) - one member produces a curtain of ascending bubbles of exhaled air that cause prey to clump for easier capture
Calcitonin
- vasodilator --> causes excessive bleeding
Felid adaptations for hunting?
- well developed sense of smell and hearing - eyes are larger than most carnivores and face forward (binocular vision...good depth perception) - most are solitary
Sarcophilus (tasmanian devils) skull adaptations
- well-developed canines - heavy molars (especially posteriorly) - well developed shearing surfaces
Callosities
- whale lice and barnacles - found in slow moving species - Ex. never seen in dolphins
What aids in cooling, strength, and reinforcement in elephant skulls?
Pneumatic cavities
Musth
Reproductive period of male elephants, characterized by increased aggressiveness and activity due to heightened hormone levels
Haustrated colon
Saccular colon (small pouches in colon) - provides extra area for digestion
Cryptic speciation
biological process that results in a group of species (which, by definition, cannot interbreed) that contain individuals that are morphologically identical to each other but belong to different species