Modern Mammals

Characteristics of the mammals:



Lactation: Feed young on milk
Hair
Skeletal features:
•
•
•
•


Heterodont dentition
Single jaw bone (dentary).
Two occipital condyles
Middle ear with three bones: incus, malleus, stapes
Endothermy
Muscular diaphragm
Lactation

Lactation: females of all mammals feed their
young on milk produced by mammary glands.

Mammary glands are completely absent from
male marsupials, but are present in male
therians (monotremes and placental mammals)
and potentially functional.

There are cases of human males producing milk
and there is a species of fruit bat in which males
produce milk.
Lactation
 Although
all mammals produce milk only
marsupials and placentals have nipples.
 In
monotremes the milk seeps from pores
in the skin and the young suck the milk
from the mother’s fur.
Hair
 Hair
has a variety of functions.
 Obviously,
insulation is its primary
purpose. Fur is made up of closely placed
hairs and the insulating value of the fur is
a function of its length.
 Longer hair allows more air to be trapped
and this reduces heat loss.
Snow leopard
http://metastwnsh.files.wordpress.com/2008/11/calculation-snow-leopard1.jpg
Hair

Hairs can be erected by erector pili muscles that
attach halfway along the hair shaft.

This raising of the fur increases the amount of
air trapped and thus the insulation level. Hair
may also be raised as a threat or defensive
display.

Although humans lack fur we retain the erector
pili muscles as vestigial structure and these
produce goosebumps.
Hair
 Hair
is composed of keratin, a fibrous
protein, and keratin is also used to make
nails, hooves and claws.
 Hair
coloration is determined by
melanocytes in the hair follicle that add
different types and amounts of pigment to
the hair as it develops.
Hair
 Exposed
hair is non-living and bleaches
with age.
 The
replacement of the fur occurs in the
process of molting in which old hairs are
lost and replaced by new ones. Most
mammals molt their hair seasonally once
or twice.
Molting mountain goat
http://ecolibrary.cs.brandeis.edu/images/
thumb50/thumb50_Mountain_goat_molting_DP4102.jpg
Hair
 In
addition to acting as insulation hair also
plays an important role in camouflage.
 The color pattern is the result of the mixing
of a variety of different colored hairs.
 Hair is also used for communication and
threat displays often include puffing up the
fur.
Vibrissae
 Vibrissae
(e.g. a cat’s or a seal’s whiskers)
are special hairs that have a sensory
function.
 Vibrissae
occur on the muzzle and around
the eyes and they are connected to touch
receptors in the skin.
Cat’s vibrissae
http://upload.wikimedia.org/wikipedia/commons/3/39/Cats_whiskers.jpg
Claws, nails, horns and hooves

Keratin is used to make not only hair but nails,
claws, hooves and horns.

Claws, nails and hooves are all the result of an
initial accumulation of keratin to protect the
bones making up the toe (phalanges) that was
later modified in ungulates into hooves, which
entirely cover the entire 3rd phalanx (the terminal
bone of the toe) and into retractable claws in
cats
http://osnhc.com/images/BASICHOOFANATOMY.jpg
Horns
 Horns
are also formed at least partially
from keratin. Rhinoceros horns are made
entirely of layers of keratin fibers.
 In
contrast, the horns of cows and
antelopes are made up of a keratin sheath
over a bony core.
White Rhinoceros
http://www.mth.msu.edu/~peller/Africa_large/rhinoceros.jpg
Skeletal features: heterodont
dentition
 Heterodont
dentition: Mammals possess
differentiated teeth (teeth that have
different forms), which carry out different
tasks: incisors, canines premolars and
molars.
 Most
mammals possess two sets of teeth.
 The first set (milk teeth) has incisors,
canines and premolars only.
Skeletal features: heterodont
dentition

The adult dentition consists of the second set of
the original teeth plus a set of molars.

Mammals are the only animals that chew their
food and the teeth are essential to this process,
which initiates the digestive process beginning
the mechanical breakdown of the food and
introducing the first digestive enzymes into the
food bolus.
Skeletal features: single jaw bone
 In
the original synapsid condition the jaw
was made up of an anterior tooth-bearing
dentary with a series of bones (the postdentary bones) forming the posterior half.
 In
this condition the articular bone of the
lower jaw articulated with the quadrate
bone of the skull.
Skeletal features: single jaw bone
 In
later synapsids the cynodonts a process
of the dentary grew back and eventually
made contact with the squamosal bone of
the skull. earliest mammals.
 This
contact eventually formed a new jaw
joint the dentary-squamosal joint.
Skeletal features: single jaw bone
 In
the earliest mammals there were two
jaw joints, but the original joint was
eventually lost, and the jaw came to
consist of a single bone the dentary and
the post-dentary bones came to form part
of the middle ear.
Evolution of dentary-squamosal joint
http://beta.revealedsingularity.net/content/articles/mammal_ear/images/jaw_artic.png
Skeletal features: three ear bones

In modern mammals there are three ear bones
the incus, malleus and stapes that transmit
vibrations from the tympanum to the oval
window of the cochlea.

These are derived from the post-dentary bones
of the synapsid jaw. The use of these bones in
hearing is not as strange as it seems at first
because Allin (1975) suggested that these three
bones always performed this function in
synapsids.
Endothermy

Along with the birds mammals are the only
groups of endothermic animals.

Endothermy allows mammals to occupy some
very harsh environments, high mountains, the
arctic, oceans that other amniotes vertebrates
do not, but it requires the animals to expend a lot
of energy to maintain an elevated body
temperature.
Endothermy
 Fur
plays a major role in insulation (and
birds are similarly insulated with feathers),
but it water it is a less effective insulator
and there mammals have turned to
blubber as an alternative.
Brown fat

Mammals also possess a specialized type of adipose
tissue: brown fat that is specially adapted to generate
heat.

Brown fat breaks down lipids and glucose to produce
heat and can generate as much as 10X as much heat as
an equivalent mass of muscle.

Brown fat is most abundant in newborn mammals (that
lack fur) and in hibernating mammals that use it to
rewarm the body quickly at the end of hibernation.
Cardiovascular system

Because of their high metabolic rates, mammals must be
able to deliver oxygen to the tissues as efficiently as
possible.

As in birds, a four chambered heart has evolved. This
ensures that the oxygenated and deoxygenated blood
are kept completely separate and maximizes oxygen
delivery to the tissues.

Again as in birds, the pulmonary and systemic circuits
are two separate loops.
Muscular diaphragm

Mammals have large, lobed lungs and these have a
sponge-like appearance because of the branching
bronchioles, which end in in blind-chambers called
alveoli.

Mammalian lungs are tidal (unlike bird lungs) and so less
efficient, but are more efficient than reptilian lungs
because they possess a diaphragm.

The expansion of the rib cage which is sealed at the
bottom by the diaphragm creates a partial vacuum that
draws air into the lungs.
Sensory systems

Mammals have exceptionally large brains and, as a
group, most depend more heavily on olfaction and
hearing rather than vision.

The dependence on olfaction and hearing is a
consequence of the fact that for much of their
evolutionary history mammals were largely nocturnal and
many species remain so today.

A notable exception to this pattern is the primates with
their diurnal habits. They primarily depend on vision.
Vision
 For
nocturnal animals visual sensitivity
(being able to form images in low light) is
more important than visual acuity (being
able to form detailed images).
 Most
mammals have retinas filled mainly
with rod cells, which are very sensitive to
light, but relatively poor at acute vision.
Vision

A high quality image can be formed only in the all-cone
fovea, and these cells also allow color vision.

Most mammals have either monochromatic or
dichromatic vision (they possess only one or two types of
cones respectively).

The mammal’s ancestors had trichromatic vision (fish
and reptiles have trichromatic vision; turtles have
tetrachromatic) but it it was lost in the ancestor of
modern placental mammals presumably because of their
nocturnal habits. Marsupials appear to have trichromatic
vision.
Vision

Among placentals some primates have
trichromatic color vision. However, it was
evolved from dichromatic ancestors and it
apparently happened twice independently in the
primates in both the New World monkeys and
the Old World monkeys and apes.

Trichromatic vision must provide a big
advantage for these animals, most likely it
enables them to spot ripe fruit and identify the
newest and most tender leaves.
Modern mammals

The modern mammals are derived from the synapsid
lineage and three lineages diverged in the Mesozoic.

The three groups can be separated on the basis of
differences in reproduction:

These are the:
 Monotremes: egg laying; platypus, echidna.
 Marsupials: young poorly developed at birth, reared in a
pouch, kangaroo, possum, wombat, koala.

Placental: young well developed at birth. During development
sustained by a placenta; horse, whale, mouse, bat, mole.
Figure 28.02
20.2
Diversification of modern mammals
 After
the Cretaceous extinction 65 mya
wiped out the dinosaurs, mammals
radiated to occupy niches previously
occupied by the dinosaurs.
 The
succeeding era the Cenozoic (65 mya
to today) is also known as the Age of
Mammals.
Diversification of modern mammals
 When
the Cenozoic began all mammals
were small and relatively unspecialized.
 The
marsupials of the time apparently
were omnivorous and arboreal (like
modern opossums), whereas the
placentals were mostly shrew-like
terrestrial insectivores.
Continental positions

In the early Cenozoic the continents were in different
positions than they are today and several were more
isolated from each other than they are today.

Africa separated from South America, Antarctica and
Australia in the Cretaceous, but South America,
Antarctica and Australia were still connected to each
other in the early Cenozoic.

Asia and North America were connected and eastern
North America and Europe also were often connected in
the early Cenozoic.
Continental Positions

Obviously since the early Cenozoic continental position
have changed.

India collided with Asia, Africa with southern Europe and
South America and North America have been linked by
the Isthmus of Panama. In each case, the joining of land
masses allowed faunas that had evolved in isolation to
mingle.

Mammalian diversity was thus shaped by a combination
of diversification in isolation followed by later merging of
faunas.
Continental Positions
 Major
diversification of the mammals
occurred at the beginning of the Cenozoic.
 Because early bursts of diversification that
gave rise to multiple modern groups
occurred on different isolated continental
land masses the higher level classification
of modern mammals reflects the influence
of the early Cenozoic distribution of land
masses.
Biogeography of marsupials

Marsupials evolved when South America, Australia and
Antarctica were still connected.

When these continents separated, those on Antarctica
were wiped out eventually by the cold climate as the
continent drifted south. However, the marsupials on
Australia and South America diversified.

Australia remained isolated and marsupials diversified
there in the absence of placental mammals. South
America eventually joined to North America and
placental and marsupial mammals came into contact
there.
Biogeography of placental
mammals
 Two
major lineages of placental mammals
the Afrotheria and Laurasiatheria
originated on separate land masses in the
early Cenozoic.
 The Afrotheria
originated in Africa; the
Laurasiatheria in Laurasia (North America,
Asia, Europe).
Cladistic Classification of the Mammalia after Lecointre and Le Guyader (2006)
Monotremata
Marsupialia
Mammalia
Xenarthra
Theria
Tubulidentata
Afrosoricida
Eutheria
Macroscelidea
Hyracoidea
Proboscidea
Afrotheria
Sirenia
Dermoptera
Scandentia
Primates
Lagomorpha
Glires
Laurasiatheria
Rodentia
Afrotheria
 Members






are :
Tubulidentata: aardvark
Afrosoricida: otter shrews, tenrecs, golden
moles
Macroscelidea: elephant shrews
Hyracoidea: hyraxes
Proboscidea: elephants
Sirenia: dugongs and manatees
Eulipotyphyles
Chiroptera
Laurasiatheria
Perissodacytla
Carnivora
Pholidota
Tylopoda
Suina
Cetartiodactyla
Ruminantia
Hippopotamidae
Cetacea
Laurasiatheria
 Members





are:
Eulipotyphles: shrews, moles, hedgehogs
Chiroptera: bats
Perissodactyla: Rhinos, horses, tapirs
Carnivora: cats, dogs, seals, bears, weasels
Cetartiodactyla: camels, pigs, deer, antelope,
hippos, whales
Biogeography of placental
mammals
 Obviously
many members of both the
Afrotheria and Lausasiatheria have
dispersed widely across the globe since
their origin.
 For
example, elephants and mammoths
spread throughout Europe, Asia and North
America after Africa joined Europe.
Biogeography of placental
mammals

In other cases, groups that had diversified on their
continent of origin were outcompeted when other groups
arrived.

For example hyraxes, which today exist only as fairly
small rodent-like animals occupied ecological roles
similar to those of pigs and antelopes before Africa
joined Eurasia.

Similarly, before South America joined North America the
large carnivores were the now extinct borhyaenoid
marsupials. Both groups were outcompeted by
competitors from the north.
Borhyaena:
http://scienceblogs.com/tetrapodzoology/Borhyaena%20from%20Argot%202003.jpg
Rock Hyrax
http://www.marietta.edu/~biol/biomes/images/desert/rock_hyrax_7042.jpg
Classification of Modern mammals

There are only about 4800 living species of mammals so
the group is not very species diverse, but it does include
the largest living terrestrial (elephants) and aquatic
animals (whales) and there is a great deal of
morphological diversity.

The mammals can be divided into three major lineages
on the basis of differences in reproduction:



Monotremes
Marsupials
Placental mammals
Figure 28.02
20.2
Classification of modern mammals
 The
marsupial and placental mammals are
united into a group the Theria because
they share a multiple traits that
monotremes lack.





Give birth to live young
Nipples
Cochlea with at least 2.5 turns
External ear
Lack of an interclavicle bone
Cladistic Classification of the Mammalia after Lecointre and Le Guyader (2006)
Monotremata
Marsupialia
Mammalia
Xenarthra
Theria
Tubulidentata
Afrosoricida
Eutheria
Macroscelidea
Hyracoidea
Proboscidea
Afrotheria
Sirenia
Dermoptera
Scandentia
Primates
Lagomorpha
Glires
Laurasiatheria
Rodentia
Monotremes

The monotremes are a small order of four species: the
duck-billed platypus and three species of spiny anteater
or echidna found in Australia and New Guinea. They
diverged from the lineage leading to the other mammals
in the Jurassic period about 180 mya.

Monotremes have several “reptilian” traits

Monotreme means “single hole” in Greek and refers to
the fact that the anus, urinary tract and reproductive tract
all empty into a single opening the cloaca, as is the case
in lizards and birds.
Monotremes

In addition, the monotremes lay eggs with a
tough leathery shell and possess an interclavicle
bone, one found in reptiles, but not in other
mammals.

However, they clearly are mammals possessing
a single dentary, three ear bones, hair, and milk
although they lack nipples and the milk seeps
from pores over a relatively wide area.
Platypus

When specimens of the platypus first arrived in Europe
they were thought to be a hoax with their strange
combination of fur and a duck-like bill.

The platypus’ bill is a highly sensitive organ that detects
faint electrical fields.

When hunting underwater the platypus sweeps the bill
from side to side and the input is processed in the brain,
a very large proportion of which is devoted to analyzing
information from the bill. The electrical input enables the
platypus to zero in on buried prey in the sediment.
Platypus
http://www.itsnature.org/wp-content/gallery/platypus-and-echidna/platypus.jpeg
Echidnas
 Echidnas
are terrestrial, covered in spines
and eat ants and termites. They have a
tubular bill.
 A fossil platypus, Obduradon, is known
that is older than the most recent common
ancestor of echidnas and platypuses,
which means echidnas evolved from a
platypus ancestor.
Echidna
Marsupials
 There
are seven orders of marsupials with
about 275 species that include such
animals as possums, kangaroos,
wombats, koalas and Tasmanian devils.
 All
marsupials have an abdominal pouch
in which the young are raised having been
born very underdeveloped, moving to the
pouch and latching onto a nipple.
Figure 28.24
20.18
Marsupials
 The
greatest diversity of marsupials
occurs in Australia where the largest
grazers and carnivores occur, but a wide
variety of opossums occur in Central and
South America.
 The living marsupials are split into two
groups: the Ameridelphia of the New
World and the Australidephia of (mainly)
Australia.
Ameridelphids

There are two orders of Ameridelphids.

Didelphimorphia: About 77 species including the North
American Opossum. The South American opossums are
small to medium sized, omnivorous and mainly arboreal.
Includes the otter-like Yapok, which catches fish.

Paucituberculata: Five species of rat opossums. This
was a much more diverse group in the past and included
the carnivorous, doglike Borhyaenoids
Yapok
http://www.bbc.co.uk/nature/wildfacts/factfiles/picpops/images/yapok02.jpg
Rat opossum
http://www.mammalogy.org/mil_images/images/mid/625.jpg
Australidelphia
 These
all occur in Australia with the
exception of one species that occurs in
South America, the mouselike monito-delmonte.
 The monito-del-monte is the sole living
member of the Microbiotheriidae, a family
that was believed to have been extinct for
more than 20 million years. It occurs in
montane forests in Chile and Argentina.
Monito-del-monte
http://www.smh.com.au/ffximage/2008/03/27/470_marsupial,0.jpg
Australidelphia
 The
monito-del-monte is considered to be
a relict member of the ancestral stock of
marsupials that migrated to Australia in the
early Cenozoic.
Australidelphia
 The
other orders of the Australidelphia are
the:




Dasyuromorphia: Tasmanian devil, numbat,
marsupial mice. Three families, 60 species.
Notoryctemorphia: marsupial mole. 1 species.
Peramelina: bandicoots and bilbies. Two
families, 21 species.
Diprotodontia: possums, flying phalangers,
koalas, wombat, kangaroos, wallabies, honey
possum. Nine families, 110 species.
Dasyuromorphia

The dasyurids are carnivorous. The marsupial mice
(more shrew-like than mouse-like) are insectivorous.

The Tasmanian devil is larger (8-12kg), doglike and
mainly a scavenger. It is found only on Tasmania having
become extinct on mainland Australia after the
introduction of dingoes. They have powerful jaws and
teeth and consume all parts of the carcass, bones and
hide.

In recent years numbers have declined as result of Devil
facial tumor disease. It is a transmissable cancer that is
spread through bites
Marsupial mouse
http://narooma.yourguide.com.au/
multimedia/images/full/178450.jpg
Tasmanian devil
http://yadogg.com/wp-content/uploads/2007/08/tasmanian-devil.jpg
Thylacine
 The
Tasmanian wolf (thylacine) is extinct.
It was a large wolf-like marsupial with a
distinctive striped back and a spectacularly
wide gape.
Thylacine
http://www.thedudeclub.com/wp-content/uploads/2008/05/thylacine.jpg
http://www.oddee.com/_media/imgs/articles/a98_Thylacine.jpg
Notoryctemorphia

Includes only one species: the marsupial mole.

The marsupial mole is very similar in appearance to the
true moles (Eulipotyphles) and the golden moles
(Afrosoricida). Marsupial moles have spades modified
out of two claws and like the other “moles” dig tunnels
and feed on worms and insects.

All three groups are blind, have no visible ears and short
or absent tails and are a great example of convergent
evolution.
Marsupial mole
http://farm3.static.flickr.com/2315/
1518610598_3efd7ceed8.jpg?v=0
http://www.nma.gov.au/shared/libraries/images/
temporary_exhibitions/extremes/extremes_large/australia/
marsupial_mole_tanami_desert_australia/files/6385/
nma.img-___TE02396-000-vi-vs1.jpg
Peramelina

This group consists of the bandicoots and
bilbies. Some of them have long ears, which
makes them look a bit Iike rabbits but they are
insectivores.

Peramelids have the 2nd and 3rd toes of the hind
foot reduced in size and enclosed in a layer of
skin to form what looks like a single toe. This
syndactylous toe is used for grooming. It is also
found in the diprotodontians.
Bandicoot
http://www.chocolateginger.com/bandicoot.jpg
Diprotodontia
 This
is the largest group of marsupials.
They are called diprotodontians because
all of them possess lower incisors that
have been modified into forward
projecting, somewhat rodent-like teeth.
Diprotodontia
 There
are three major groupings within the
diprotodontians:



Six families of smaller arboreal species
including possums, cuscuses and several
gliding phalangers including the sugar glider.
Vombatiformes: which includes the terrestrial
wombats and arboreal koalas.
Macropodoids: which includes the small
omnivorous rat kangaroos and the bigger,
herbivorous true kangaroos and wallabies.
http://www.convictcreations.com/
animals/images/sugargliger.jpg
Sugar gliderhttp://www.cartage.org.lb/en/themes/sciences/zoology/ClassMammalia/
Mammals/OrderDiprotodontia/SugarGlider/sugarglider.jpg
Brush-tailed phalanger
http://www.naturephoto-cz.com/photos/
others/brush-tailed-phalanger-62285.jpg
Spotted Cuscus http://members.optusnet.com.au/%7Ealreadman/cuscus1%20hjb.jpg
Koalas: http://www.southernmamas.com/wp-content/uploads/2008/01/koala_baby.jpg
Southern hairy-nose wombat
https://secure7.ozhosting.com/cws/
graphics/popups/wildlife_
mammals_Southern_hairy_nose
_wombat2.jpg
Wombat http://www.quantum-conservation.org/EEP/WOMBAT.jpg
Rock Wallaby
Eutherian mammals
 The
Eutherian or placental mammals
support their developing young using a
chorioallantoic placenta which brings the
blood supplies of mother and offspring into
close contact so that food and gases can
be effectively exchanged.
Cladistic Classification of the Mammalia after Lecointre and Le Guyader (2006)
Monotremata
Marsupialia
Mammalia
Xenarthra
Theria
Tubulidentata
Afrosoricida
Eutheria
Macroscelidea
Hyracoidea
Proboscidea
Afrotheria
Sirenia
Dermoptera
Scandentia
Primates
Lagomorpha
Glires
Laurasiatheria
Rodentia
Eulipotyphyles
Chiroptera
Laurasiatheria
Perissodacytla
Carnivora
Pholidota
Tylopoda
Suina
Cetartiodactyla
Ruminantia
Hippopotamidae
Cetacea
Xenarthra

Thirty species of armadillos, sloths and
anteaters. They are widespread in South and
central America and one species the ninebanded armadillo occurs in the southern United
States.

They are either toothless (anteaters) or have
simple peg-like teeth. All have strong claws that
they use for digging, ripping open termite
mounds or to hang suspended in trees (sloths)
Pink fairy armadillo
http://gallery.nen.gov.uk/
gallery_images/0709/0000/0267/
pink_fairy_armadillo_mid.jpg
Giant Anteater
http://www.junglewalk.com/
animal-pictures/622/
Giant-anteater-4059.jpg
Afrotheria

The group includes a set of species that
originated in Africa some of which later
dispersed more widely.

Members are :






Tubulidentata: aardvark
Afrosoricida: otter shrews, tenrecs, golden moles
Macroscelidea: elephant shrews
Hyracoidea: hyraxes
Proboscidea: elephants
Sirenia: dugongs and manatees
Tubulidentata

The Tubulidentata has only one species the
aardvark, which occurs in Africa.
 It is nocturnal, pig-size, and feeds on termites
and ants. It rips its way into termite mounds
using its powerful claws.
 Its teeth are unusual (hence the name
Tubulidentata). They lack enamel and instead of
a single pulp cavity, each tooth has several
upright parallel tubes of vasodentin (a modified
dentin) each of which has its own pulp canal.
Aardvark:
http://animals.nationalgeographic.com/staticfiles/NGS/
Shared/StaticFiles/animals/images/primary/aardvark.jpg
Afrosoricida

Historically the members of the Afrosoricida
were part of a polyphyletic group called the
“Insectivora.”

This was a hodge-podge of small mammals that
ate insects and as well as the Afrosoricids
included among others the elephant shrews,
tree shrews, and true shrews all of which are
now included in different groups.
Afrosoricida

Otter shrews, tenrecs, golden moles.
 All originated in Africa and all are small animals with
dense fur, small eyes and short powerful legs.
 Tenrecs occur only on Madagascar and they have spines
scattered through the fur or just spines.
 Otter shrews look like small otters with elongated bodies.
They have a valve of tissue that seals off the nostrils
when diving.
 Golden moles resemble marsupial moles and talpid
moles and the front paws have two strong claws used for
digging.
Giant Otter shrew
http://cas.bellarmine.edu/tietjen/RootWeb/Insectivora.jpg
Streaked tenrec
http://media-2.web.britannica.com/eb-media/75/22175-004-92ADC9E4.jpg
Hedgehog tenrec
http://animaldiversity.ummz.umich.edu/
site/resources/mzm2/46.mr2.jpg/medium.jpg
Cape Golden mole
http://www.biodiversityexplorer.org/mammals/afrosoricida/images/eos03241_663x498.jpg
Macroscelidea

Elephant shrews or sengis are found only in
Africa and there are 16 species. They eat
invertebrates fruits and seeds.

They are small weighing from 2 ounces to a
pound. They have long legs, which make them
swift runners and have long, mobile elephantlike noses. In their home range they maintain a
network of paths along which they run quickly to
escape predators.
Black and rufous Elephant shrews:
http://www.peabody.yale.edu/exhibits/treeoflife/images
/black_and_rufous_elephant_shrews.jpg
Hyracoidea

Hyraxes are small, tailless and stocky and weigh
2.5-3.5 kg. They look a bit like groundhogs.
 Found in Africa and the Middle East, hyraxes are
surprisingly good climbers and some are
arboreal. Others are found on rock
outcroppings.
 They have elastic pads on their feet, which they
moisten with sweat to help them grip when
climbing.
 Like rodents, hyraxes have continuously growing
incisors and lack canines. There is gap between
incisors and premolars (called a diastema).
Rock Hyrax: http://www.ucmp.berkeley.edu/mammal/mesaxonia/hyrax.jpg
Proboscidea

Elephants. The largest terrestrial mammals they
weigh up to 6 tons.
 There are two living species the African and
Asian elephants, although African forest and
savannah elephants are genetically distinct and
there are at least 4 subspecies of Asian
elephant.
 They lack lower canines and the third upper
incisors have been modified into tusks and the
nose and upper lip into the characteristic trunk.
Proboscidea

Elephants are dominant herbivores and occur in
a wide variety of habitats from savannah to
mountain forest (up to 5,000 m).
 They live in matriarchal family groups and
maintain close family bonds throughout their
lives.
 Elephants range widely in search of food. They
require 100-200kg of vegetation daily and can
be very destructive of vegetation and frequently
come into conflict with humans when they raid
crops.
African Elephant
http://myanimalblog.files.wordpress.com/
2008/02/elephant.jpg
Asian Elephant
http://www.naturephoto-cz.com/photos/sevcik/asian-elephant--elephas-maximus-1.jpg
Sirenia

The sirenians consist of five species of dugongs
and manatees, which are large aquatic grazing
mammals that typically occur in large family
groups.

They have no hind limbs and the forelimbs have
been modified into swimming paddles. They are
slow-moving and don’t dive actively and sink by
regulating the amount of air in their lungs.
Sirenia

Manatees and dugongs differ in the shape of
their tails (it’s bifurcated in dugongs).

All living species are found in rivers, and coastal
waters in warm seas and are endangered as a
result of habitat destruction, pollution and conflict
with humans. One species, Steller’s sea cow,
was hunted into extinction in 1768, only 27 years
after it was discovered.
Dugong
http://www.unep.org/dewa/images/
dugong-coverpic-for-web.jpg
Manatee
http://www.goddardscuba.com/
Schedule/2008/manatee.jpg
Dermoptera





There are two species of
colugos (or flying lemurs) one
found in the Philippines and
the other in Java and Borneo.
They have an extensive gliding
membrane that stretches
between the limbs and from
the hind limbs to the tail.
They can glide up to 150m at a
time and feed on fruits, leaves
and flowers.
http://www.eurekalert.org/
images/kidsnews/janecka3LR.jpg
Colugo
http://www.americazoo.com/goto/index
/mammals/dermoptera.htm
Scandentia

Tree Shrews (19 species) are small arboreal mammals
that are quite squirrel like in appearance.

They are diurnal animals that live in the trees and
underbrush in forests in southeast Asia.

They have primate-like brain and skull anatomy as well as
almost opposable toes. However, the dentition is
insectivorous.

Various taxonomists have over the years grouped the tree
shrews with insectivores, rodents, lagomorphs, primates
and even marsupials. The current placement as sister
group to the primates is based on gene sequence data.
Tree shrew: http://www.ryanphotographic.com/images/JPEGS/Tree%20shrew.jpg
Primates

Tarsiers, lorises, bush babies, lemurs, New
World and Old World monkeys, gibbons, apes,
humans.
 Primates have opposable thumbs and
opposable big toes, which allows both hands
and feet to grip branches.
 Orbits are forward facing for binocular vision.
The brain is well developed in many groups and
they are often highly social.
Lorisiformes
Strepsirrhini
Primates
Lemuriformes
Tarsiformes
Platyrrhini
Cercopithecoidea
Hylobatoidae
Hominoidea
Pongidae
Hominoidae
Gorillinae
Hominidae
Homininae
Homini
Panini
Classification of the Primates after Lecointre and Le Goyader (2006)
Lorisiformes

The lorises and lemurs are members of the strepsirrhini
and they share a characteristic dental comb of four
incisors and two forward-projecting canines . This is
used to strip vegetable material (e.g. tree gum) when
feeding and in grooming.

Lorisiformes (10 species of lorises and bush babies) are
small, large-eyed (200-300 g) nocturnal, arboreal
primates with round heads.

They occur in Africa, India and southeast Asia and are
omnivorous eating insects, fruits and tree gum.
Lorisiformes
 Lorises
(including the potto) are
chameleon-like and slow moving. They
can’t jump and depend on camouflage and
immobility for protection.
 The
six species of bush baby (or galago)
are much more agile and active and run
and jump to hunt and to escape predators.
Slow Loris
http://www.sfgate.com/n/pictures/2006/06/14/loris.jpg
Potto
http://www.dumondconservancy.
org/dc2005/images/web/primate
%20pics/Prosimians/Loridae/
Potto%201.jpg
Bush baby
http://www.hlasek.com/foto/otolemur_crassicaudatus_
db9035.jpg
Lemuriformes

There are 22 species of lemur and they occur only on
Madagascar where they evolved in isolation from
competition with monkeys.

They range is size from the mouse-lemurs (5 inches long
excluding the tail and 55 g) to the indri (up to 70cm and
10kg). They include the familiar ring-tailed lemur and the
bizarre aye-aye.

Lemurs are arboreal, but do not brachiate. Instead they
jump vertically from branch to branch.
Mouse lemur
http://animals.nationalgeographic.com/staticfiles/NGS/
Shared/StaticFiles/animals/images/primary/mouse-lemur.jpg
Ring-tailed Lemur
http://www.erikvp.com/Images09/ring-tailed-lemur.jpg
Indri: http://www.bushhouse-madagascar.com/
images/indri_indri_madagascar01.jpg
Lemuriformes: aye-aye

The aye-aye is a solitary nocturnal species that
eats fruit and insect larvae, which it digs out of
wood using powerful forward projecting incisors.

It has large ears, which it uses to detect insect
larvae and a greatly elongated, very thin, third
finger, which it uses to winkle the larvae out of
their holes.
Aye-aye:
http://animals.nationalgeographic.com/
staticfiles/NGS/Shared/StaticFiles/animals/
images/primary/ayeaye.jpg
Aye-aye hand
http://alphabeticaprime.files.wordpress.com/2008/02/aye-aye_hand.jpg
Lemuriformes

All lemurs are threatened by habitat destruction
as Madagascar’s human population has boomed
and large areas of natural habitat have been
converted into farmland or cut for lumber.

Fourteen species of lemur have become extinct
since humans arrived on Madagascar about
2000 years ago including some that were as big
as orang-utans.
Tarsiiformes




Three species of tarsier
and all are small and
arboreal with greatly
enlarged orbits.
They have long hindlimbs
and are excellent
jumpers.
They are nocturnal and
fed on insects and small
vertebrates.
Found on islands in
southeast Asia.
Tarsier:
http://blog.makezine.com/_wpcontent_uploads_2007_08_tarsier.jpg
Platyrrhini

The Platyrrhini are 51 species of New World
monkeys and include two main groups: the
callithricids: marmosets and tamarins and the
cebids: capuchins, squirrel monkeys and howler
monkeys.


They live in tropical rain forests and other forests
and possess a prehensile tail which they can
use to grip branches when climbing.
Platyrrhini

Marmosets and
tamarins are small
150-700 g) colorful
monkeys that often
have mustaches or
manes of hair. Their
nails have been
modified into claws.
 They live in
monogamous family
groups.
Tufted eared marmoset
http://cache.virtualtourist.com/
3862569-Tufted_ear_marmosetEstado_da_Bahia.jpg
Platyrrhini

The cebids eat fruits,
leaves, seeds, insects
and small vertebrates
and social
organization ranges
from monogamous
pairs to large
polygamous groups.
One species, the
northern night
monkey, is nocturnal
Red Howler monkey
Spider monkey
http://www.aguilaharpia.org/photos3/Panama-Spider-Monkey-3.jpg
Cercopithecoidea

The Old World monkeys includes 82 Afro-Asiatic
species that include two main groups: the large
bodied, mostly terrestrial baboons and
macaques (cercopithinae) and the smaller, more
delicately built vervets, colobuses, and langurs
(colobinae).

Most species eat fruit and leaves, but baboons
frequently hunt hares and young gazelles. All
Old World monkeys possess a tail, but it is not
prehensile.
Black and white colobus
http://www.game-reserve.com/images/wildlife
/primates_other/guereza_colobus_monkey_02.jpg
Baboons http://www.animalwebguide.com/Baboon-2.jpg
Hylobatoidae


These are the nine
species of gibbons and
siamangs, which are
slender, tailess apes with
very long arms and a
highly flexible wrist, which
allows them to brachiate.
They move awkwardly on
the ground.
They live in family groups
in the tropical forests of
southeast Asia and feed
almost entirely on fruit.
Hoolock Gibbon:
http://www.pittsburghzoo.org/upload/Image/hoolock-gibbon.jpg
The “Great Apes”
 The
five species of “great apes” are the
orang-utan, gorilla, chimpanzee, bonobo
and human.
 All are large with a highly folded cerebral
cortex in the brain and all lack tails.
Pongidae

The orang utan is the sole member of the
Pongidae and they inhabit the tropical rain forest
of southeast Asia.
 Orangs are solitary the only great ape that
spend almost all of its time in the trees. They
are excellent brachiators.
 The diet consists largely of fruit and leaves
occasionally supplement with insects, eggs and
small vertebrates.
 They are greatly threatened by loss of rainforest
habitat in Borneo and Sumatra.
Orang Utan
http://naturescrusaders.files.wordpress.com/2009/04/orangutan-male.jpg
Gorillinae

Gorillas are the largest living primate and live in
small family groups led by a single dominant
male. They are terrestrial during the day but
sleep in trees at night.
 They are vegetarians and occur in the lowland
forests of west Africa and mountain forests in
Rwanda and eastern Congo.
 They are threatened by poaching and
deforestation.
Panini
 Two
species: the chimpanzee and bonobo.
 They live in bands of 10-30 individuals.
Most of the diet is vegetarian, but chimps
will hunt and kill baby antelopes, pigs and
small monkeys.
 Occur in central and western Africa.
http://phineasgage.files.wordpress.
com/2007/06/070617chimp.jpg
http://www.awf.org/files/3972_image2_western_gorilla_MWatson.jpg
Homini
 Humans:
largely hairless great ape.
 Posesses advanced reasoning and
communication capabilities and a high
degree of technological sophistication.
 Highly social. Widespread.
Glires: Lagomorpha

The lagomorphs consist of about 80 species of rabbits,
hares and pikas. Strictly vegetarian they have a well
developed cecum to facilitate digestion of vegetation.

Rabbits and hares have long legs and are fast runners.
They also have long ears (especially in species from hot
regions).

Pikas are primarily found in mountainous, alpine terrain.

They were once grouped with the rodents as they also
have prominent incisors used for gnawing. However,
they have two pairs of incisors in the front of the mouth
(the 2nd pair are vestigial and located behind the first).
Pika
http://media-2.web.britannica.com/eb-media/16/3516-004-67E3395A.jpg
Glires: Rodentia
 Rodentia:
Rodents. The largest group of
mammals with more than 2000 distributed
worldwide.
 Includes
more than 1,300 species of rats
and mice as well as squirrels, mole rats,
woodchucks, beavers, gerbils, lemmings,
capybaras, and agoutis.
Rodents


The key to their success is their chisel like upper
and lower incisors that grow continuously.
The front of the tooth has a thick layer of enamel
but the rear has a layer of dentine that is much
softer.
 The movement of the upper and lower incisors
against each other wears down the dentine and
leaves a very sharp chiseled edge that enables
the rodents to open even the hardest seeds. To
assist in their chewing the rodents also have
highly enlarged masseter muscles.
Beaver teeth
http://www.arkive.org/media/
20/206467D2-694F-4269-BFBC9925111529EE/Presentation.
Large/photo.jpg
http://www.usefilm.com/images/
4/8/6/8/4868/1246269-medium.jpg
Rodents

Various species of rats and mice have spread
across the globe as commensals with humans.
They are enormous pests of stored foods
especially grains and almost certainly there are
more rodents on earth than all other mammals
combined.
 They also are major vectors of disease such as
typhus and bubonic plague. In the past 1,000
years rodent spread diseases have probably
been responsible for more humans deaths than
all wars combined have caused.
Cladistic Classification of the Mammalia after Lecointre and Le Guyader (2006)
Monotremata
Marsupialia
Mammalia
Xenarthra
Theria
Tubulidentata
Afrosoricida
Eutheria
Macroscelidea
Hyracoidea
Proboscidea
Afrotheria
Sirenia
Dermoptera
Scandentia
Primates
Lagomorpha
Glires
Laurasiatheria
Rodentia
Eulipotyphyles
Chiroptera
Laurasiatheria
Perissodacytla
Carnivora
Pholidota
Tylopoda
Suina
Cetartiodactyla
Ruminantia
Hippopotamidae
Cetacea
Eulipotyphyles (“insectivores”)

This group of almost 300 species includes much of what
was historically included in the “insectivores,” desmens,
shrews, moles, hedgehogs, and solenodons.
 They are small to very small (the pygmy white-toothed
shrew at 2g is the world’s smallest mammal).
 Highly active with very high energy needs, mostly
terrestrial insect eaters and occur worldwide.
 Generally the senses of smell and hearing are most
important and they tend to be solitary and aggressive.
 Both moles and hedgehogs have ecological equivalents
in other groups, the result of convergent evolution.
Figure 28.16
20.28
Chiroptera

Bats. Nocturnal flying mammals with forelimbs
modified into wings. The flight membrane is
stretched between long fingers (the metacarpals
are enormously elongated).
 Many species use echolocation. About 925
species, second only in size to Rodentia.
 There are two major groups the large
megachiroptera (the fruit bats) which have longmuzzled fox-like faces and mainly eat fruit and
the microchiroptera which have flattened faces,
small eyes and large ears.
http://fireflyforest.net/images/firefly/2007/
February/Lesser-Long-nosed-Bat-1.jpg
Epauletted fruit bat
http://www.taos-telecommunity.org/epow/
EPOW-Archive/archive_2008/
EPOW-080317_files/
P1160663%20wahlbergs%20epauletted%20fruit%20bat_s.jpg
Perissodactyla

Odd-toed ungulates. Horses, zebras, asses, tapirs,
rhinoceroses. 18 species. They have a long muzzle with
strong prehensile lips.
 The main supporting axis of the hind limbs passes
through the third toe.
 Horses donkeys and zebras have a single toe, rhinos
and tapirs have three toes on the hind feet, but tapirs
have 4 on the forefeet (but the third toe is the strongest)
 All herbivorous with teeth adapted to chewing
vegetation. The caecum in the intestines (analagous to
the rumen in ruminants) is enlarged and anaerobic
fermentation of cellulose by bacteria takes place there.
Figure 28.41
20.32
Carnivora

Medium to large flesh-eaters. Cats, dogs,
weasels, badgers, mongooses, racoons, bears,
seals, sealions. 271 species.
 Teeth specialized for killing. Canines are long
and pointed and molars have numerous slicing
cusps for shearing meat.
 The last upper premolar and first lower molar
are modified into carnassial teeth that work like
scissors to cut meat away from bones.
http://www.cartage.org.lb/en/themes/sciences/zoology/
Animalclassification/OrderPrimates/carnassials.jpg
Pholidota

Pangolins. Seven
species of scale covered
anteaters with powerful
claws. They lack teeth
and have a tube-like
snout with a very long
tongue (up to 16” long).
 They are mainly nocturnal
and are found in Africa,
India and southeast Asia.
 To escape predators they
curl into a ball so tightly
that a man cannot unroll
them.
http://www.vulkaner.no/n/africa/
somalia/pangolin.jpg
Cetartiodactyla

Traditionally, the members of this group were
classified as two groups the Artiodactyla: eventoed ungulates pigs, deer, cattle, antelopes,
hippopotamuses and the Cetacea: whales and
dolphins.
 Recently, it has become clear that the cetaceans
are embedded within the Artiodactyla and evolved
from hoofed predators called mesonychids.
 Cetaceans are more closely related to hippos
than hippos are to the other members of the
Artiodactyla. As a result, the Cetartiodactyla has
been created.
“Traditional Articdactyls”

There are four groups in the Cetartiodactyla that
would have been included within the previous
Artiodactyla.





Tylopoda: Camels and vicunas. 6 species.
Suina: pigs, warthogs, peccaries. 19 species.
Ruminantia: Deer, bison, cattle, antelope. 191
species.
Hippopotomidae: Hippos 2 species.
Two or four toes sheathed in hoofs. Most are
ruminants and possess multi-chambered
stomachs.
Eulipotyphyles
Chiroptera
Laurasiatheria
Perissodacytla
Carnivora
Pholidota
Tylopoda
Suina
Cetartiodactyla
Ruminantia
Hippopotamidae
Cetacea
Figure 28.41
20.32
Cetacea
 Whales
and dolphins. Aquatic diving
mammals. Anterior limbs modified into
flippers, posterior limbs absent, possess
large rear fluke for propulsion, nostrils
modified into blowhole on top of head. 78
species.
Cetacea

The two basic divisions of the cetaceans are the toothed
whales (Odontoceti) and the baleen whales (Mysticeti).
 Toothed whales (e.g. sperm whale, killer whale,
dolphins) have homodont dentition. The teeth are used
to capture prey, but not for chewing.
 Baleen whales (e.g., blue whale, humpback whale, sei
whale) feed on smaller prey that they filter using their
baleen, which is made of keratinized extensions of the
epidermis. Baleen whales take in a mouthful of water
and press their tongue against the baleen to squeeze out
the water and then swallow the food trapped inside the
mouth.
Figure 28.42
Humpback whale