Mammalian Orders and Families

Order Monotremata

Subclass Prototheria

• echidnas and duck-bill platypus (5 species)

• Australian Region

• oviparous (lay shell covered eggs)

• cloaca (common tract to digestion, excretion, and reproduction)

• no teeth in adults

• no external pinnae

• epipubic bone present

• venomous spine on hind foot in male (spurs)

• mammary glands without nipples

Order Didelphimorphia

Subclass Theria - Infraclass Marsupialia

• opossums (127 species)

• Neotropical and Nearctic Regions

• most generalized marsupials

• 50 teeth (primitive number for marsupials and mammals)

• opposable and clawless hallux (thumb)

• marsupium is present to absent

• tail often long and prehensile (5th appendage)

Order Paucituberculata

Subclass Theria - Infraclass Marsupialia

• shrew or rat opossums (7 species)

• resemble shrews with elongate heads and reduced eyes

• feet unspecialized

• tail long but not prehensile

• no marsupium

Order Microbiotheria

Subclass Theria - Infraclass Marsupialia

• 3 species

• Neotropical Region (isolated in forested areas of Andes mountains

• tail accumulates fat for hibernation (moderately prehensile)

• 50 teeth

• marsupium present

Order Dasyuromorphia

Subclass Theria - Infraclass Marsupialia

• marsupial mice and cats, Tasmanian wolf, Tasmanian devil, and numbat (88 species)

• Australian Region

• 42-46 teeth

• plantigrade in most; digitigrade in cursorial forms

• tail long and furred, not prehensile

• marsupium often absent

Order Peramelemorphia

Subclass Theria - Infraclass Marsupialia

• bandicoots and bilbies (30 species)

• snout elongate and pointed

• 46-48 teeth

• hind limbs longer than fore limbs

• tail often long but not prehensile

• rearward opening marsupium

• Australian region

Order Notoryctemorphia

Subclass Theria - Infraclass Marsupialia

• marsupial mole (2 species)

• Australian Region (Australia only)

• fossorial

• eyes are covered by skin and nonfunctional (vestigal)

• reduced pinnae

• enlarged claws

• marsupium partly divided into 2 areas

Order Diprodontia

Subclass Theria - Infraclass Marsupialia

• kangaroos, wallabies, wombats, koala, etc. (158 species)

• Australian Region

• wide array of shapes, sizes, and food habits due to the number of forms

Order Afrosoricida

Subclass Theria - Infraclass Placentalia

• tenrecs and golden moles (55 species)

• Ethiopian Region

• small weak eyes and reduced pinnae in most

• teeth heterodont, often with large incisors

• no auditory bullae

• testes never scrotal

• baculum in some

• 2 genera have venomous saliva

• echolocation in some species

Order Eulipotyphla

Subclass Theria - Infraclass Placentalia

• moles, shrews, and solenodons (557 species)

• small weak eyes and reduced pinnae in most

• teeth heterodont, often with large incisors

• no auditory bullae

• testes never scrotal

• baculum in some

• 2 genera have venomous saliva

• echolocation present in some species

• Worldwide except Australia and southern Neotropical regions

Order Macroscelidea

Subclass Theria - Infraclass Placentalia

• elephant shrews (20 species)

• Ethiopian region

• terrestrial forms

• large eyes and ears

• very long snout that is somewhat moveable

• relatively long limbs (specialized for rapid movement relative to insectivora)

• complete auditory bullae and zygomatic arch

• diurnal

Order Scandentia

Subclass Theria - Infraclass Placentalia

• tree shrews (23 species)

• Oriental Region (India to Philippines)

• arboreal forms resembling small, long-nosed squirrels

• large eyes

• 5 digits with strongly recurved claws

• long tail, usually furred

• complete auditory bullae and zygomatic arch

• mostly diurnal

Order Dermoptera

Subclass Theria - Infraclass Placentalia

• flying lemurs or colugos (2 species)

Order Chiroptera

Subclass Theria - Infraclass Placentalia

• bats

• Worldwide distribution

• only flying mammal

• mostly small

• wing composed of hand with membrane

Suborder Megachiroptera

• 186 species

• large eyes and well-developed vision

Suborder Microchiroptera

• 945 species

• eyes usually small

• ears highly variable, most with tragus

• echolocation is primary means of orientation and prey capture

Family Talpidae

moles

• front feet broadened for digging

• head and forelimbs modified for burrowing

• ears usually lack external pinnae; small eyes

• fur is thick, soft, and velvety

Family Soricidae

shrews

• upper middle incisors elongated for capture of invertebrate prey

• snout long and thin for prey capture

• ears have small external pinnae

• very small eyes

• generally live in litter, under logs, or other burrows, not fossorial

• Pigmented teeth

Family Phyllostomidae

leaf-nose bats

• wide array of food habits—insectivorous, carnivorous, nectivorous, and frugivorous

• forelimbs for flight

• teeth modified to fit food habits

• echolocation, but variable

Family Mormoopidae

leaf-chinned bats

• insectivorous

• echolocate

• colonial

Family Desmodontidae

vampire bat

• sanguinivorous

• able to walk

Family Vespertilionidae

10 genera, 30 species in N.A.

• Worldwide (most widespread family in the world)

• common in Utah and most of N.A.

• considerable variation in life histories—some colonial, some solitary; some migratory, some not; some mate in spring, others in fall; some live in nursing colonies, others are solitary

• insectivorous

• echolocate

Family Molossidae

2 genera, 6 species

free-tailed bats

• insectivorous

• echolocate

• large colonies (10^5 or 10^6 in caves of southwest U.S.

• guano deposits

Order Primates

lemurs, monkeys, apes, and humans (519 species)

• usually arboreal, some terrestrial

• plantigrade locomotion

• usually with nails, some with claws

• large braincase in some

• sight well developed; smell reduced

• tropical and subtropical in both new and old world, humans are cosmopolitan

Family Hominidae

Humans

Order Carnivora

• 4-5 digits

• terrestrial, arboreal, amphibious, and aquatic

• wide variety of forms

• teeth heterodont or homodont

• baculum present

• worldwide distribution

Family Felidae

cats (most carnivorous of carnivores)

• rostrum shortened to the extreme of carnivora

• claws retractile

• Not as cursorial as canids, stalk and short run

• Carnassials will developed

Family Canidae

wolves, dogs, foxes, jackals, etc.

• long rostrum with large nasal chamber

• well-developed sense of smell

• claws are not retractile

• most cursorial of the carnivores

• Primarily carnivorous, but opportunist which leads to omnivorous diet

Family Ursidae

bears (1 genus, 3 species)

• carnassial pair is less-developed

• plantigrade and ambulatory

• primarily carnivorous but omnivorous

• winter inactivity, but not true hibernation

Family Mustelidae

marten, ermine, fisher, weasel, mink, wolverine, badgers, otters

• usually small and short-legged

• mostly carnivorous

• carnassials well-developed, except in otters

• anal scent glands well-developed

• terrestrial to nearly aquatic

Family Mephitidae

skunks

• usually small and short-legged

• mostly omnivorous

• carnassials well-developed

• anal scent glands well-developed

• terrestrial

Family Procyonidae

raccoon, ringtail, coati

3 genera, 3 species

• much more of an omnivore than a carnivore

• shearing of carnassial pair almost lost

• much greater climbing ability than other carnivora families

• long tail for balance

Family Otariidae

eared seals and sea lions

4 genera, 4 species

• small external ear

• better adapted for land use than other pinnepeds, hind flippers can be brought under body and used for terrestrial locomotion

Family Phocidae

earless seals

6 genera, 10 species

• no external ear

• hind flippers useless on land

Family Odobenidae

Walrus (1 species in the world)

• large tusks from canines useful in gathering mollusks from sea floor

Order Hyracoidea

hyraxes or dassies (6 species)

• 2 long, continuously growing upper incisors

• 4 chisel-like lower incisors

• 4 digits on forelimbs (1 nonfunctional), 3 digits on hindlimbs

• hooves with soft elastic pads on each functional digit

• Ethiopian region

Order Proboscidea

elephant (3 species)

• largest terrestrial mammal

• pillar-like limbs (graviportal)

• upper incisors are evergrowing tusks

• no canines or lower incisors

• air cells in skull to reduce weight and for muscle attachment

• Oriental and Ethiopian regions

Order Sirenia

dugong, manatees, sea cow (5 species)

• only aquatic mammal herbivore

• aquatic from coastal marine to riverine

• external nares high on skull

• forelimbs paddle-like, hindlimbs vestigial in muscle

• tail is an externally flattened fluke

• tropical coastal regions

Family Trichechidae

manatees (1 species)

• only completely aquatic forms that are herbivores

• live in coastal waters (Florida)

Order Perissodactyla

horses, asses, zebras, tapirs, rhinos, etc.

8 species

• terrestrial, adapted to unguligrade cursorial locomotion

• odd-toed ungulates

• weight is borne on middle digit which is largest

• cannot bend hindlimbs enough to get up hindfeet first when laying down

• skull elongate

• premolars and molars similar in size and shape

• diastema between front and cheek teeth

• simple stomach

• no horn or antlers; rhino horn

• Ethiopian, Oriental, Palearctic, Nearctic, Neotropical regions

Family Equidae

feral horses and burros (2 introduced species)

• cursorial

• herbivore

• teeth adapted to wear from grass as a food—high silica content

• hypsodont

Order Artiodactyla

pigs, hippos, camels, deer, giraffe, cattle, bison, pronghorn, dolphins, and whales (362 species)

• terrestrial, adapted to unguligrade cursorial locomotion

• even-toed ungulates

• weight is borne on the third and fourth digits

• can stand hindfeet first when laying on ground

• molars and premolars not as massive as in Perissodactyla

• simple to complex stomach

• Ethiopian, Oriental, Palearctic, Nearctic, and Neotropical regions

Family Suidae

feral hogs or wild boar (1 introduced species)

• omnivores

• no horns or antlers

• tusks from upper canines

Family Tayussuidae

javelinas or peccaries (1 species)

• smaller than suids

• omnivores but more herbivorous than suids

• no horns or antlers

• tusks from canines

Family Cervidae

Wapiti, deer, moose, caribou

• antlers that shed annually

• herbivores, browsers more than grazers

• may form large migratory herds during certain times of year

• economically important

Family Bovidae

bison, mountain goat, muskox, mountain sheep, cows

• permanent horns

• herbivorous, mostly grazers

• cursorial in part due to their evolution in grasslands

• teeth adapted to grazing habits

Family Antilocapridae

pronghorn (1 species)

• evolved in and endemic to North America

• horns branch and keratin sheath is shed annually

• the fastest of the cursorial mammals in North America

Suborder Whippimorpha

hippos, whales, dolphins, porpoises, and narwhal

• aquatic with fusiform bodies

• hindlimbs absent, but vestigial pelvic girdle present

• forelimbs paddle-shaped but limb elements not externally visible

• worldwide marine, some species riverine

Parvorder Mysticeti

baleen whales

• planktivorous (do not echolocate)

• 2 external narial openings on top of head

• baleen (cornified epethelium) in place of teeth

Parvorder Odontoceti

toothed whales

dolphins, orcas, etc.

• single narial opening on top of head

• teeth present, echolocate

Family Balaenopteridae

blue whale, humpback whale, minke whale

• the largest whales (up to 140,000 kg and 27m)

• baleen

• blue whale can eat 3,600 kg of krill per day

Family Delphinidae

dolphins and orcas

• teeth

• generally larger than porpoises

• wave-shaped dorsal fin

• usually have elongate rostrum or beak

• carnivorous

Family Phocoenidae

porpoises

• lack rostrum or beak

• triangular-shaped dorsal fin

• carnivorous

• smaller than dolphins (usually <2m)

Order Cingulata

armadillos (22 species)

• no incisors or canines

• cheek teeth rudimentary or absent

• no enamel on teeth

• extra articulation on lumbar vertebrae to strengthen lumbar region

• Neotropical and Nearctic regions

Family Dasypodidae

armadillos (1 species)

• few to many teeth

• homodont

• horny epidermis over bony plates

• identical quadruplets

Order Pilosa

sloths and American anteaters (16 species)

• no incisors or canines

• cheek teeth rudimentary or absent

• no enamel on teeth

• extra articulation on lumbar vertebrate to strengthen lumbar region (anteaters)

• Neotropic region

Order Pholidota

pangolins or scaly anteaters

• terrestrial and fossorial

• horny scales on neck, back, and tail (rolls into “ball” for defense)

• strong limbs and large claws

• long, thin snout with protractile tongue

• no teeth in adults

• muscular stomach, swallows pebbles to grind food

• Oriental and Ethiopian regions

Order Tubulidentata

aardvark (1 species)

• terrestrial and fossorial

• strong limbs and large claws (digs into ant and termite mounds)

• long, thin snout with protractile tongue

• no incisors or canines

• 20 cheek teeth but all remain in gums

• teeth columnar with dentine surrounding pulp

• large burrow systems

• only eutherian order with a single species

• Ethiopian region

Order Rodentia

rats, mice, squirrels, beaver, porcupine, etc.

• most common order of mammals (31 families)

• terrestrial, amphibious, fossorial, arboreal, saltatorial, and glissant

• skull shaped for gnawing

• 2 upper and 2 lower chisel-like incisors (grow continuously)

• enamel only on front of incisors

• long diastema between incisors and cheek teeth (no canines)

• limb structure and tail length highly variable

• Worldwide

Family Aplodontidae

mountain beaver (1 species)

• most primitive living rodent

• size of a small rabbit

• terrestrial colonies in moist stream edges

• herbivorous, hay piles

Family Erethizontidae

porcupine (1 species)

• quills

• herbivore, apical meristem and cambium layers of conifers but do graze other plants

Family Cricetidae

mice, rats, voles, lemmings, muskrats

• mouse-like forms with long tails and generalized limbs

• teeth fit food habits

• exhibit herbivory, granivory, and insectivory

• terrestrial, amphibious, scansorial, arboreal, and fossorial

• population cycles of 3-4 years in lemmings and Northern voles

Family Myocastidae

nutria (1 introduced species)

• amphibious form introduced into the southeast area of the U.S.

• herbivorous on terrestrial vegetation

• pest

• crop, irrigation, and waterfowl habitat damage

• resembles a beaver in habits but smaller with long, round tail

Family Geomyidae

pocket gophers

• external, fur-lined cheek pouches

• fossorial with incisors that extend forward and lips that close behind teeth

• powerful claws and strong forelimbs

• herbivorous above and below ground

Family Heteromyidae

kangaroo rats and pocket mice

• adapted to arid/semi-arid habitats

• some can survive without water

• granivorous

• bipedal to quadrapedal

• bipedal forms are saltatorial (some ricochetal) with large hindfeet and long tail

• external, fur-lined cheek pouches

Family Dipodidae

jumping mice

• coniferous to deciduous forests, wet meadows

• very long tail and long feet

• herbivorous, granivorous, and insectivorous

Family Sciuridae

chipmunks, squirrels, marmots, and prairie dogs

• generalized body with long tail in most, but short in some fossorial types

• Diurnal

• some forms hibernate

• glissant in Glaucomys

Family Castoridae

Castor canadensis, largest N.A. rodent

• amphibious herbivore

• specialization for gnawing and carrying branches underwater

• broad, flat tails

Order Lagomorpha

pikas, rabbits, hares

• terrestrial with cursorial or saltitorial locomotion

• skull resembles that of rodents

• 4 upper and 2 lower incisors

• 2nd upper incisor peglike and directly behind 1st incisor

• incisors grow continuously

• long diastema between incisors and cheek teeth (no canines)

• hindlimbs longer than forelimbs

• tibia and fibula fused for strength

• very short tail

• worldwide except islands and Australian regions

Family Ochotonidae

pika (1 genus, 2 species)

• talus slopes in mountains of N.A.

• short, rounder ears, no tail, very small

• build hay piles for winter

Family Leporidae

hares and rabbits

• cursorial

• hindlegs longer than forelimbs

• relatively long ears

• herbivorous