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approx how many described species are there for the class mammalia



what are the most species rich mammalian orders? where most mammalian diversity comes from

40% = Rodentia = mice/rats/allies
25-30% = Chiroptera = "handwing" -> bats


list 5 reasons to study mammals

1. mammals hunted for food, sport -> economic value
2. Sociality
3. Models for disease studies, drug development (pharmacological), Zoonoses (diseases that can be transmitted from animals to humans- plague, lyme disease etc.)
4. Conservation -> flagship species(Panda), translocation/reintroduction
5. Basic natural history/scientific research


define a mammal synapomorphy and list the 3

shared characteristics/traits among all members of a clade of organisms inherited from a common ancestor (sometimes these traits can be modified):
-physical traits/physiological characters shared between all mammals (extant or extinct)
1. hair (at some point in time)
2. all mammals feed their young with milk
3. incus, mallus and stapes (inner ear bones)


altricial vs precocial

born helpless/more dependent vs more developed and independent of mom


describe hair and the composition of hair and when it evolved

evolved approx 300mya (synapsids)
-hair does not fossilize
-no homologous structure in nature -> unique!
-Formed by alpha-keratin: fibrous protein, tightly coiled which also forms nails/claws
-protein filament that arises from follicles embedded in the dermis


why does hair moulting occur?

-weather/season related-> phenology, can get worn down due to moisture/heat/mechanical wear/sunlight


list the functions of hair

defence, insulation, sensory organs, camouflage and communication


how does hair serve the purpose of insulation, what are the types of hair?

* Under hairs: wool, fur, velli
Guard hairs: longer, stiffer hairs to protect underhairs
-Piloerection = hair stands up (may convey emotion or trap heat)
-Protects from UV damage


describe the hair of a polar bear

a polar bear has black skin and transparent hair that seems to be white because it lets in light energy and enters hair shaft where it is defused and scatters which refracts and appears white. highly adaptive for camouflage
-hair can get worn down and dirty and straggly looking and may indicate and older bear or perhaps that it is the end of summer so they havent moulted their hair yet
(they live off fat stores until they hunt and moult again)


how does hair serve the purpose of defence ? Explain what porcupines do as their defence

spines = modified guard hairs
-physical - eg. against predators
-quils are barbed (of porcupine) and comes to very sharpe point that can easily enter predators skin. barbs flare out once embedded into the skin which makes quill removal difficult. most predators once quilled can no longer eat and starve to death
-the quills have antimicrobial properties (but not always) in their sebum to prevent death of porcupine if it self quills itself or family.
-they are hunted by Mantes Pennanti (fishers) that swipe at the face of a porcupine to make them bleed to death
-cougars take porcupines head on and dont care about getting quilled
-can show aggression by rattling their quills


how can hair serve the purpose of sensory organs?

- vibrissae = whiskers
-tips have proprioceptors (sea lions)
-cat whiskers can vibrate and sense whats around them and dictate the size of tight spaces
-highly innervated -> lots of blood supply/ nerve endings
-vibrissae also on chin and forelegs to position prey to deliver death blow


how can hair serve the purpose of camouflage ? ex tigers?

tigers have stripes to break up the outline of their body so its not a distinctive structure to visually oriented organisms


how can hair serve the purpose of communication?

-aposematic -> skunks warn off predators before spraying
-identification -> zebras create optical allusions
baby zebras can imprint moms pattern once its born and cant be adopted if losses mom


why have some mammals evolved to be (relatively) hairless? what problems could they have?

-Naked mole rats -> live underground where they is no UV rays
-Elephant -> so large they dont need insulation from hair, they want to lose heat (also rhinos and hippos)
Problems: UV damage, mechanical abrasion, insects/ectoparasites (lice, flies)
-cetaceans -> want to stay hydrodynamic (no hair helps) but could suffer from hypothermia so they increase their blubber to maintain heat
-humans have most of their hair on possible areas of friction like pubic area (create scent) and their head


what are the incus and malleus derived from?

jaw bone (quadrate and articular)


how do bats protect themselves from self deafening from echolocation

echolocation is high pitched frequencies that have enough energy for sound wave/vibration to bounce back but such high frequencies could cause damage so bats can separate their inner ear bones


what are mammary glands?

= cistern and teat that produce milk
alveolus structure


describe the composition of milk and how it is for seals vs black rhino

milk has fats/sugars/proteins
lactose and oligosaccharides (varies between sp)
fat and protein composition varies as well
-Seals have high fat content to ensure pup grows fast and is weaned very fast (a few days)
-black rhinos have the most watery milk (>1% fat) and a long weaning period (up to 2 years)
-if grazing herbivores, not much fat past on to offspring


what could be the evolutionary origin of milk?

to keep eggs moist? thin shells would mean drying out


Often (2013) proposed a theory postulating the evolutionary origin of milk. outline that theory

it had to have nutritional benefit to the hatchling (had to have some mutation to make it more nutritious)
-smaller body size = smaller eggs/offspring = less developed so you have to look after them by feeding milk and it would be better if baby gets more nutrients from it


sebaceous glands?

unique to mammals but not all mammals have them
-sebum= oily/waxy matter that conditions/coats hair (want hair in good condition, not matted) but too much sebum isnt good either (causes acne)


primary and secondary function of sweat glands

primary: thermoregulation
secondary: excretion of cellular waste
* not all mammals have sweat glands (dogs pant and release water from their tongue)


Scent glands (how do deer use them)

unique to mammals
-can leave an olfactory signal/scent through secretions of scent glands (can attract mate this way)
ex. Deer have lots of exocrine and lacrimal glands (scent glands all over their body) and can release pheramones and can show that they are in heat and can have particular scents for identification for their offspring


what is a dentary? and why did it become a single bone

= mandible
-has become a single bone in class mammalia -why? Didn't need the articulation so they fused together and now one bone = more force/leverage
-the smaller articular and quadrate bones are now used for hearing


secondary pallate

allows you to breathe and chew simultaneously (don't want the two to mix)
-allows you to constantly be getting a supply of oxygen which is needed for cellular respiration and to maintain metabolism


skeletal features? What does the fusion of bones mean?

long bones have epiphyses which is the end part of the bone
-bone fusion means that we have determinant growth


describe the other mammalian synapomorphy, the muscular diaphragm

muscular visceral organizer (separates the lungs from the abdomen) and its role in producing high intra-abdominal pressure.
-The human is the only mammal which keeps the diaphragm parallel to the ground even during locomotion
-During each respiratory cycle, this muscle changes shape to increase the size of the chest cavity to allow air to enter the lungs.
-equips mammals with a high capacity for oxygen consumption and may have been key to the evolution of high metabolic rates and warm blood.


describe the other mammalian synapomorphy, the enucleated erythrocytes

Erythrocytes are the red blood cells
-Enucleation – the process by which the nucleus is extruded by budding off from the erythroblast – is unique to mammals. has critical physiological and evolutionary significance in that it allows an elevation of hemoglobin levels in the blood (carry more oxygen) and also gives red cells their flexible biconcave shape.
-purpose God gave them was to supply the oxygen our cells need, not express genes, or really any purpose requiring a nucleus
-Higher oxygen levels means animals can grow larger and still maintain the supply of oxygen to their muscles.


name the three false synapomorphies for mammals

endothermy (high metabolism)
Vivipary -giving birth to live young
intelligence -slippery slope (octopus is the smartest invertebrate)


what kind of dentition do mammals have

*heterodont (have more than just one type of tooth, canines, incisors, molars)- differentiation between form and function between lineages
-teeth are not unique to mammals but become morphologically diversified in terms of shape and function which was key to adaptive radiation in mammals
=highly complex and efficient (feeding)
-generally two sets of teeth


what does it mean to have two sets of teeth

-deciduous ="milk"/lacteal teeth (molars usually absent)
-> dont need teeth to nurse
-adult = permanent teeth
-some mammals are monophyodont having only one set of teeth that never stop growing while others are polyphyodont (sharks constantly lose their teeth and replace them)


describe between the two evolutionary origin theories of teeth:
Concrescence theory vs Differentiation theory

Concrescence (Kutenthal and Rose): proposes that multicusped teeth in mammals evolved by joined development (integration) of several primordia of simple teeth inherited from mammalian ancestors; tooth concrescence has been accompanied by a shortening of jaws. Natural selection favours certain forms over others. need to have variation of teeth between individuals and variation must be heritable (if trait is heritable and has advantage, then will persist/spread)

Differentiation (Cope and Osborn) :
the complex multicusped teeth in mammals evolved by differentiation from one simple-shaped tooth of mammalian ancestors
cones/conules (small) -> Cusps (bigger)


what are the ancient differences between metatherian and Eutherian teeth

2-3 premolars, 4 pairs of molars
Eutherian: reversed
4 premolars, 3 pairs of molars


concomidant (naturally accompanying) changes of dentition

housed in upper and lower jaw
-different cusps coming up (animal gravitating towards specific food source)
changes in teeth -> changes in jaw structure -> changes in mastication -> changes in food storage and digestion/nutrient processing -> changes in many other things such as metabolism
-teeth are heavy which means there will be changes to jaw structure and musculature


Describe the Teeth Structure and the 4 main parts

crown = anything above gumline (exposed tooth)
root = below gumline (embedded socket of jaw)
1. Enamel- highly mineralized, thin but very hard surface. primary function is the protection for underlying tooth). =hardest substance of mammalian skeletal structure and cant be replaced
2. Dentine- softer (fewer minerals), provides support for the tooth structure
3. Cementum- thin layer that covers the roots, can be replaced
4. dental pulp cavity- blood vessels, nerves and connective tissue (vascular part of tooth)


what is attrition in teeth context

wearing down of teeth


thecodont dentition

"rule" in mammals
= mammal teeth are embedded in boney sockets/alveoli of jaw)
vs acrodont(no sockets for teeth) and pleurodont (teeth are fused by their sides)


what are the types of teeth

incisors, canines and cheekteeth (molars and premolars)
-not all mammals have theses types present and some mammals have very few teeth; some have none *depends on diet


explain how ant-eaters and whales function without teeth

whales have keratin and use tongue to filter feed
ant eaters are myrmecophagous(eat ants) and process food by using bumpy/tough soft connective tissue in their mouths/throat to grind them up


describe incisors and give mammalian examples

cutting, grabbing (primary function but not all mammals use them in that way)
-have one root
-ex. tusk = incisor of an elephant exposes thick/hard dentine that keeps growing and they use them for combat/protection, digging water holes and strip off and knock down trees to eat
-ivory = specialized dentine
ex. rodents use incisors for biting hard substances and the lower incisor chips away at the soft dentine on the upper incisor to keep it sharpe (self sharpening). they also have a large gap in the bucal cavity/mouth between teeth (diastema)
ex. Norwal tusk = modified incisor
->only two upper teeth that are functional but usually only one tusk comes through. males use them for competition during mating season


describe canines and give mammalian examples

stabbing, punchering (killing teeth)
-one root
-highly innervative to sense where they are placing their teeth on prey so they dont get away or get hurt by prey
->sabbortooth condition no longer seen in extant cats (veryyy long canines)
ex. walruses have two modified canines (made from ivory/specialized dentine) used to get back onto the sea ice by anchoring themselves and using leverage. also use them for protection from each other/predators and to chip at ice to make breathing holes (also lots of nerve endings on vibrisae to find food)
ex. Musk deer have modified canines for males to fight each other to gain mating rights


describe cheekteeth and give mammalian examples

= premolars and molars
premolars = bicuspid, molars = tricuspid(+)
-for mastication/chewing and grinding/crushing
-raised tiny structures or ridges on occlusal surface
-have different patterns and morphologies


What is the only order where you need to differentiate between premolars and molars and how do you do it?

-> they have carnassials
-> they are the first molars in the lower jaw and the last premolars in the upper. (P4/M1)


tribosphenic molar

has 3 cusps (protocone, paracone and metacone) and appears in almost all lineages of mammals



cones that are elevated
-> raised tiny structures or ridges on occlusal surface
->have different patterns and morphologies


name the different types of cusp patterns

bunodont, secodont, selenodont, lophodont, zalambdodont, dilambdodont, quadrate,


bunodont cusp pattern?

a few shearing edges but also flat places and low cusps
-dentition that is adapted to eating both plants and animals (omnivores)
ex. domestic pigs, humans, bears


secodont cusp pattern?

carnassials (P4/M1) = shearing and cutting flesh
-used by carnivores to cut through meat/bones


selenodont cusp pattern?

-they dont have large peaks in the cusps
-have elevated ridges of cementum that contacts plant matter and aids to grind them up (cementum can regenerate)
-low crowns, and crescent-shaped cusps when viewed from above
-dentine/enamel exposed
ex. sheep, deer


lophodont cusp pattern?

ridges cover almost entire surface of molar (they have multiple ridge lines)
- large ridges/lophs = loxandonty
-ridge of enamel connected to each other to grind up tough vegetation (tree branches/wood/hard seeds)
ex. elephant, rates/mice


zalambdodont cusp pattern?

lamda shaped cusp line


dilambdodont cusp pattern?

-2 lambda shapes on one tooth
-grind up insects
-lots of ridge lines and cusps to process food source
ex. bat, insectivorous mammals


quadrate cusp pattern?

-hypocone added to increase SA to grind plants
-can have extensive modification -> can add conlids to further increase SA
ex. tough vegetation (bamboo - red panda)


brachydont vs hypsodont

low(rodents) vs high (horses) crown tooth to buy more time before wear and tear of tooth

Hypsodont- pattern of dentition with high-crowned teeth and enamel extending past the gum line, providing extra material for wear and tear. Some examples of animals with hypsodont dentition are cows and horses; all animals that feed on gritty, fibrous material


describe the reproductive biology of monotremes

-1. ay eggs (platypus: 1-2, echidna: 1)
-meroblastic eggs= high yoke content
->young have a egg tooth to break out of egg
2. *Cloaca = oviducts open into common urogenital sinus (structure similar to reptiles)
*monotreme = single opening
-males: testes lie within body cavity (no external scrotum)
3. no nipples, milk secreted by glands in the skin and young do not suckle


what are the pros and cons to ovipary and vivipary ?

-less expensive for mom to lay egg
-moms not doing anything so more safe from predators
-once an egg is laid, parent cant pass on diseases like you can through a placenta

-have to make a safe environment for egg
-incubation-> mom has to stay with egg to keep it warm which restricts her movement and can't feed or mate


describe the reproductive biology of metatherians

marsupial egg ovulated, fertilized, then coated by shell membrane (similar to monotremes)
-has combination of yoke and uterine secretions = source of nutrition for embryo in early development (2/3 gestation)
-shell membrane is shed and egg sinks into depression in uterine wall for last 1/3 gestation
-doesn’t really implant to extent that it does in placentals
-has pouch for young


describe the marsupial pouch

-2 months to over 1 year (the larger the metatherian, the longer time spent in the pouch)
-not all pouches are the same
(backward facing, rudimentary, no pouch)


describe the reproductive biology of eutherians

-lowest yoke content
-embryos receive almost all nutrition through extensive connection with the placenta directly from diffusion of mothers blood supply (chorio-allantois, hemochordia)
-placenta is not a synapomorphy for mammals as some reptiles are ovoviviparous in which they lay eggs but hatch them inside and form a rudimentary placenta


placenta functions and costs

-deliver nutrients from mom to young
-deliver waste from young to mom
-separate mothers immune system from attacking embryo (placenta = "immune privilege"/tolerance)
-barrier for diseases
-produces hormones to keep pregnancy going
-have to direct energy/resources to development of placenta
-too big/complex to reabsorb so has to be ejected (some eat it for nutrients)
-mom could haemorrhage and fetus could die if placenta tears
-some diseases can still be transmitted via placenta (HPV)


metatheria vs eutheria gestation period?

gestation period is shorter or about equal to estrous cycle (2-5 weeks)
-birth occurs before next estrous cycle
-newborns are TINY (ie. <1g)
-typically much longer gestation period
-pregnancy stops estrous cycle (females don't come into heat during pregnancy because there is no point to get pregnant again when you have a young to take care of)


lactation vs gestation in metatherians and eutherians

metatherians are lactation specialists (invest more time in lactation) as their young spend much more time developing out of the uterus in the pouch to compensate for having such a short gestation period
-For the same body size, marsupials invest shorter times in
gestation, but longer times in lactation.
eutherians are gestation specialists as they invest longer times in gestation


describe marsupial process from mating to young having independence

1. mating occurs
2. after ~2 month gestation period, live birth occurs and parent mates again but eggs is in diapause
3. after ~240 days lactation (milk has high carbs and low protein/fat) with young attached to nipple, the joey leaves the pouch to learn
4. still nursing but milk shifts to high protein/fat and low carbs, less reliant on milk and more on plant matter.
5. weaning of 1st joey and birth of second joey occurs and mating happens again and 3rd egg enters diapause
*mom can force embryo to stay or go into diapause if environmental conditions not suitable for young


what is musth?

male elephants undergo musth or puberty that lasts approximately a month and happens 3 or 4 times a year (better chance of mating)
-raise in testosterone, sexual activity and aggression
-adaptive for their reproductive biology as females only are in estrous for a few days
-males release secretions from glands in their tempos called *temporin and rumble (infrasound, low frequency) which attracts the females
Other males avoid going near the area where they hear the "musth rumble)


what are the advantages and disadvantages of longer bouts of lactation vs longer bouts of gestation

-more reliant on mom outside mother
-not protected from outside influences
-energetic costly
-if mom isn't getting enough nutrients or gets hurt, milk wont support young
- milk is a reliable food source
-nutrients tailored to needs/physiology of young
-developing young in a more stable environment
-young more developed and so less dependent on mom for survival (dont nurse as long)
-placenta protects from diseases
-placenta is not foolproof to diseases
-cant mate again for awhile
-if something happens to mom, young dies too


is this hypothesis true:
eutheria outcompete marsupials (partly) because their reproductive mode is superior

-no marsupial litter exceeds 1% of maternal body mass-(newborns <1 g)
-Mass of litters in eutherians variable, but can be as
high as 50% for some rodents and shrews
-some eutherians have relatively BIG offspring
-Investment by weaning more informative of offspring development - Length of gestation increases with
maternal body mass in placentals, but no relationship
in marsupials (flat line, all gestation lengths short)
-most mammals wean offspring at about 40% of adult size
-So, total investment in amount of tissue of young at
time of weaning is similar. BUT…
Lactation is less efficient way to transfer energy to
young, so total mass of young at weaning doesn’t
capture full cost of investment. (better to develop inside the womb than out)
*therefore, it is more expensive to be a metatherian but whether it is a better or worse reproductive strategy is subjective.


Time: conception to weaning
->for metatherians and eutherians

Takes marsupial longer than placental to raise young to
same size (weaning age). Females probably “pay”
more energetically for same mass of weaned offspring.


semelparous vs Iteroparous

only 1 reproductive bout in your lifetime (only mate and reproduce once)
-> more rare
-> ex. Antechinus (all die at the end of mating season because all energy put into offspring. they have high cortisol levels)
multiple reproductive bouts in lifetime
-> more common


describe between the three different types of iteroparity

monoestrous: 1 reproductive event per year (iteroparous but over multiple years)

polyestrous: many estrous cycles (ovulations) per year

seasonally polyestrous: multiple estrous cycles but limited to certain times of the year


what are examples of mammals who are either monoestrous, polyestrous or seasonally polyestrous?

monoestrous = Dogs, wolves, foxes and bears

Polyestrous = cattle, pigs, mice, rats

Seasonally polyestrous = horses, sheep, goats, deer, cats


what is the evolutionary cost of metatheria reproductive strategy?

marsupials are not totally altricial at birth:
-young must be able to crawl to pouch using their front legs (need an active NS)
-need to be able to breathe on their own (functional lungs)
-have to attach to nipple and suckle (need to have developed stomach, intestines, kidneys, mouth)
-> So more advanced in some aspects than placental embryo at that stage.
**Therefore, there is an evolutionary constraint on development of other forms (young can't be born any other way as they have specific reproductive requirements) - less diverse because of it
-More limited range of body sizes (not as huge?).
Perhaps developmental options more limited due to
reproductive mode.
-mammals are significantly more diverse in eutheria


which reproductive strategy is better? that of metatheria or eutheria

Lactation is most energetically costly period of reproduction, and less efficient means of energy transfer to young. Marsupials eventually raise offspring of similar relative body sizes as placentals, but costs them more time and energy.
Newborn marsupials need to be able to crawl to
pouch or teat, suckle, breathe, digest... More advanced than placental embryo at same stage. But no wings, hooves, or flippers!
Very little investment by marsupials in individual
offspring by time of birth, can adjust litter sizes according to environmental conditions, etc. Could be a positive in unpredictable environment.


approx how many species of carnivorarns? and what are the two suborders?

300 species
sub orders: caniformia (dog like) and feliformia (cat like)


what is the synapromorphy for feliformia

auditory bullae is double-chambered = two bones joined by a septum (cover ear ossicles)


what are 4 traits of the sub order feliformia?

1. shorter rostrum
2. fewer teeth
3. specialized carnassials -> generally more carnivorous
4. ambush predators (short bursts of speed)


what are the 7 families of feliformia?

* 1. felidae (very diverse)
* 2. hyaenidae (4 living representative species)
*3. Herpestiae (mongoose family)
4. viverridae- tree mongoose
5. nandinidae
6. prionodontidae
7. eupleridae


describe the family felidae (distribution, hunting style, diet, etc.)

-felidae = fields
-widespread geographic distribution; native to all continents except Australia and Antartica
-diverse habitats
-most diverse pelage/fur patterns
-obligate carnivore= diet consisting mainly of meat, because it does not possess the physiology to digest vegetable matter
-solitary/ambush hunters


define digitigrade and plantigrade

walk on tiptoes vs walk on souls of feet


describe the claws of felidae? what about the cheetah?

all have claws made of keratin but not the same as our finger nails
-claw is off the ground at rest position to prevent wear/tear but usually cant see claws in this position through their fur/hair
-they extend their tendon to contract their claws
-not all felidaes do their claws this way, cheetahs need more traction when they're running so they have long claws that dig into the ground. tail for balance, large lungs, foot pads, light thin body, large heart (everything geared for maximum acceleration- 140km/hr)
-claws mainly used for holding/immobilizing prey, inflicting injuries, climbing, protection


teeth of felidae?

enlarged canines used for killing, puncturing prey
- carnassials P3
- 3/3, 1/1, 3/2, 1/1 x2 = 30 teeth


eyes of felidae? how can they hunt at night

large orbits for primary visual modality = eyes
-tapetum lucidum = reflects light back to retina, enables retina to have another chance to process photons and form an image
-most are nocturnal hunters but not all; many hunt at dawn and dusk
- at twilight their shadows are elongated and they have more camouflage
-diurnal (ex. cheetahs) cant run fast in the dark so they hunt during the day


describe the family Hyaenidae

reduced diversity as many are now distinct
-dog like gate, relatively long fur, kill like dogs(eat prey alive,), jaws are dog like and they can eat bone)
-> thought they should be in caniformia but actually more similar to cats as shown by molecular genetics
-some are myrmemcophagy (eat ants/termites) = aardwolf
-spotted hyaenas are very good hunters (unlike shown on movies)
-pups commit fratacide (kill siblings)


describe the family Herpestidae

-short, compact legs to dig (ground dwelling prey)
-generally solitary hunters but have few rep. species that are more social
-have immunotoxins (for snake venom) that allows them to eat venomous snakes (venomous animals actively inject venom/poison)
genus: merecats ->highly evolved sociality (to the extreme)


what are the 9 families of caniformia?

1. canidae - dogs
2. ursidae - bears
3. ailuridae - red panda (use to be recognized in racoon family/procyonidae)
4. procyonidae- racoon
5. mustelidae -weasels,otters
6. mephitidae -skunks
7. pinnipedia: odobenidae(walrus), otariidae (eared seal) and phocidae(ture seal)


describe the family canidae

digitigrade - tiptoes
-carnivores, but many species are highly omnivorous
-highly social (packs)
-42 teeth = 3/3, 1/1, 4/4, 2/3
ex. red fox (diet similar to coyotes)


compare between the grey wolf and coyote (canidae)

grey wolf:
not around people
-eat mostly only meat
-long snout, wet/moist noise (primary means of identifying each other = smell)
-large pinnae (good hearing) -> howling communication
-smaller counterpart to wolfs
-highly adaptable and omnivorous (therefore do better around people)
->like to eat garbage and domestic pets
-dont have to live in packs to do well


describe the family ursidae (and the 4 bears)

american black bear:
-plantigrade, highly omnivorous, altricial young born at the beginning of hibernation
-most development outside of womb because not enough space in womb
-females grizzly bears mate every 1-2 years and male bears will kill her cubs because she isnt in heat if she has cubs
*better to come across a black bear than a grizzly as they are smaller and less likely to fight (they climb trees)
-grizzlys more carnivorous than black bear
-Polar bear: strict carnivore (eat seals)
-Panda bear: specialize on bamboo but dont extract much nutrients from what they eat, cubs take a long tome to develop (all pandas belong to china)


describe the family Mustelidae

-long tailed weasel, sea otter, wolverine (largest weasel)
-have to constantly eat food because they have a high SA to vol ratio
-they moult
-musk gland = synapomophy
-weasels strictly carnivorous


describe the family mephitidae

-extreme musk gland, more omnivorous diet


describe the procyonidae family

-most omnivorous in this family
-highly reduced carnassials


Pinnipedia families? odobenidae, otariidae and phocidae

odobenidae(walrus) - more developed pectoral muscles to prop themselves up, has tusks
otariidae (eared seal) - developed carnassials, dog like head structure (longer snout)
phocidae(ture seal) - lay on stomach, fat milk to pack on weight for blubber, largest carnivoran = southren elephant seal. longer skull with sharpe pointy/peglike teeth. holds wet slippery prey (fish), chews a bit and then swallows it whole (dont have chewing teeth or defined carnassials)