Insectivora

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Created by:

trisme11  on March 13, 2010

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mammalogy

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Insectivora Order

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Insectivora

Previous Order of Insectivora
6 Families
tenrecs
golden moles
hedgehogs and gymnures
solenodons
shrews
moles and desmans
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Previous Order of Insectivora 6 Families
tenrecs
golden moles
hedgehogs and gymnures
solenodons
shrews
moles and desmans
Order Insectivora now split into 3 orders Molecular phylogenies actually suggest this grouping is polyphyletic
Afrosoricida
Erinaceomorpha
Soricomorpha
Afrosoricida golden moles, tenrecs
Erinaceomorpha hedgehogs and gymnures
Soricomorpha solendons, shrews, moles, desmans
Three other Orders that were previously in Order Insectivora Macroscelidae- elephant shrew
Scandentia- tree shrew
Dermoptera- colugos
What do the groups in Order Insectivora share• generally small
• pentadactyl with plantigrade locomotion
• rostrum tends to be long
• pelage often consists only of guard hairs (modified in
some forms as spines)
• external pinnae are small or absent
• small braincase with smooth cerebral hemispheres
• auditory bullae are absent - instead there is a ringshaped
tympanic bone.
• testes usually abdominal, or if in scrotum, then
anterior to penis (as in marsupials).
• cloaca is present in some.
• jugal is reduced or absent.
• pubic symphysis is reduced.
Teeth in Order Insectivora
Some retain tribosphenic molars
teeth are close-rooted,
molars are either W-shaped (dilambdodont - A)
or V-shaped (zalambdodont - B). Many species retain
the primitive dental formula - 3/3, 1/1, 4/4, 3/3 (44 teeth)
W-shaped teeth
dilambdodont A shrew and moles
V-shaped teeth
zalambdodont B golden moles and solenodons
Super Order: Afrotheria
Afrosoricida (golden moles and tenrecs)
Macroscelidea (elephant shrews)
Tubulidentata (aardvark)
Sirenia (manatees, dugongs)
Hyracoidea (hyrax)
Proboscidea (elephants)
Family Tenrecidae Order: Afrosoricida
tenrecs and otter shrews

- all 27 species of tenrecs are restricted to the island of Madagascar
- otter shrews are found in west-centralAfrica
- some suggest the otter shrews should be in a separate family
Gymnures
hairy hedgehogs or moon rats inhabit moist jungle terrain in various locales of Southeast Asia

Full grown specimens closely resemble large rats, or the opossum, with which it shares similar habits and ecological niches.
Gymnure Body The gymnure's body plan is believed to resemble that of the earliest
mammals, with a large toothy head about 1/3rd the length of the total body, a naked furless tail for balance and thermoregulatory purposes, and a plantigrade stance.
Gymnures Senses outstanding sense of smell, and tactile response in the snout region.
Gymnure Eating Habits• gymnures are primarily carnivorous. They are nocturnal or
crepuscular: they come out to forage at twilight or in the night
to search the forest floor, using smell to find the animals that
they eat.
• gymnures eat various arthropods, mice, small reptiles and
amphibians, with occasional fruit and fungi.
Family: Erinaceidae (hedgehogs, gymnures)
Order: Erinaceomorpha
• hedgehogs have barbless spines, while gymnures have no spines
• found in Africa, Europe and Asia
• hedgehogs are nocturnal and mainly terrestrial, with some
semiarboreal.
• they are omnivorous - vertebrates, eggs, fruit, carrion, in addition to inverts • spines in hedgehogs are soft at birth, and have not broken
the skin. They harden a few weeks after birth.
• in a defensive posture, the animal rolls up in a ball, using a
band of muscle lateral to the ventrum
Anointing When the animal encounters a new scent, it will lick and bite the source, then form a scented froth in its mouth and paste it on its spines with its tongue It is believed that anointing camouflages the hedgehog with
Only insectivore to use hibernation?
Erinaceus europaeus others may aestivate on a daily basis to save
Family: Solenodontidae (solenodons)
2 species -1 restricted to Cuba, the other to Haiti and the Dominican Republic.

Solenodons are venomous, nocturnal, burrowing, insectivorous
mammals. • submaxillary glands produce toxic saliva, which flows into the bite via grooved 2nd incisor.
Diet of Solenodons The diet of solenodons consists largely of insects,
earthworms, and other invertebrates, but they also eat vertebrate, carrion, and perhaps even some living vertebrate prey such as small reptiles or amphibians.
Solenodons Echolocation • may be capable of echolocation - they produce high frequency clicking sounds.
Solenodons Appearanceextremely elongated cartilaginous snouts, long, naked, scaly tails, small eyes, and coarse, dark brown to black
hair.

The snout is flexible, and in the Haitian solenodon, actually has a ball-and-socket joint at the base to increase its mobility.
This allows the animal to investigate narrow crevices where potential prey may be hiding.
Family: Talpidae (moles, shrew-moles, desmans)
Order: Soricomorpha

• distributed throughout Europe, Palearctic, Asia, Japan, and
North America
Order: Soricomorpha
Family: Talpidae (moles, shrew-moles, desmans)
• ranges from shrews who are fossorial to desmans which are
semi-aquatic
• the shrew-moles, the smallest of the family are fossorial, but
also forage on the surface and can climb small shrubs
American Shrew Mole Neurotrichus gibbsii
the smallest North American mole
• its found in the Pacific Northwest and British Columbia
Shrew Moles' Dietconsists primarily of earthworms and other small
invertebrates found in the soil. The mole may also occasionally
catch small mice at the entrance to its burrow.
Because their saliva contains a toxin that can paralyze earthworms,
moles are able to store their still living prey for later consumption.
Mole Underground Larders researchers have discovered such larders with over a thousand earthworms in them.
Before eating earthworms, moles pull them between their squeezed
paws to force the collected earth and dirt out of the worm's gut.
Mole (fossorial with appropriate morphology) • extreme modification of the pectoral girdle and appendages -
including rotation of the fore-feet.
• pinnae reduced or absent
• keeled sternum
• fusiform
• small eyes
Star nosed moles
easily identified by the eleven pairs of pink fleshy appendages ringing their snout which are used as a touch organ with more than 25,000 minute sensory receptors, known as Eimer's organs.
Desmans
are small semi-aquatic mammals that inhabit Russia,
Ukraine and Kazakhstan.

It constructs burrows into the banks of ponds and slow moving
streams, but prefers small, overgrown ponds with abundance of
insects and amphibians.

Like other moles, it is functionally blind and obtains much of its
sensory input from the touch sensitive Eimer's organs at the end of
its long, bi-lobed snout. The hind feet are webbed and the tail
laterally flattened - specializations for its aquatic habitat.
Desman fur used to be highly sought after by the fur trade
Family: Soricidae (shrews) Order: Soricomorpha
• 26 genera and 376 species
• organized into 2 subfamilies:
• Soricinae are the red-toothed' shrews(Tribes: Soricini, Blarinini, Neomyini)
• Crocidurinae are the 'white-toothed' shrews
• average 10-15 g
Smallest Shrews
Suncus etruscus (2 g) and Sorex hoyi
Largest Shrews Suncus murinus (100 g)
Shrew with webbed feet Nectogale elegans and Sorex palustris.
Which shrew species is mentioned in the Jungle Book?
Asian House Shrew (Suncus murinus) aka Chuchander
Shrew Body Characteristics • most have short legs and are plantigrade.
• small eyes, pointed rostrum, short dark pelage
• a typical shrew skull has no auditory bullae or jugal and
therefore an incomplete zygomatic arch
Shrew Teeth • the first upper incisor is hooked and has a posterior cusp (arrow),the first lower incisor is long and procumbent (box), the uppermolars are dilambdodont
Shrew Teeth Throughout LifeThe teeth of shrews wear down throughout life, a problem made more extreme by the fact that they lose their milk teeth before birth, and therefore have only one set of teeth throughout their lifetime.

Apart from the first pair of incisors, which are long and sharp, and the chewing molars at the back of the mouth, the teeth of shrews are small and peg-like, and may be reduced in number.
Red Tooth Shrew
• red-toothed shrews have a characteristic pigmented enamel

The enamel of the tips of their teeth is reddish due to iron
pigment. The iron deposits serve to harden the enamel and
are concentrated in those parts of the teeth most subject to
wear.
Shrew DietShrews are opportunistic predators taking whatever prey season, habitat or opportunity presents. Prey includes mice, moles, salamanders, frogs, birds, bird eggs, all types of insects, slugs, snails, isopods, spiders, millipedes and centipedes.

Shrews will also eat roots, berries, nuts,fruits, fungi and general
vegetable materials if prey is limited or if these materials are abundant.
Shrew Behavior• shrews are generally terrestrial, although some specialize in
climbing trees, living underground, in the subniveal layer, or even hunting in water.

They are very active animals, with voracious appetites and unusually high metabolic rates. Shrews eat 80-90 % of their own body weight in food daily.
Shrew Senses • they have small eyes and generally poor vision, but have excellent senses of hearing and smell.
Shrew sleep patterns They do not hibernate, but are capable of entering torpor. In winter, many species undergo morphological changes that drastically reduce the animal's body weight. Shrews can lose between 30% and 50% of their body weight, shrinking the size of bones, skull and internal
organs
Shrew VenomSome species of shrew (Blarina and Neomys) are venomous.
Shrew venom is conducted into the wound by grooves in the
teeth.

The saliva of the Northern short-tailed shrew contains a
protease, used to paralyze and subdue or kill its prey and this
is sufficient to kill mice.

The poisonous saliva is secreted from submaxillary glands,
through a duct which opens at the base of the lower incisors,
where the saliva flows along the groove formed by the two
incisors, and into the prey.
Echolocation in terrestrial animals The only terrestrial mammals known to echolocate are two genera of shrews (Sorex and Blarina) and the tenrecs of Madagascar
Shrews that echolocate vagrant shrew (Sorex vagrans),
common Shrew (Sorex araneus),
Northern short-tailed shrew (Blarina brevicauda).
Echolocation in ShrewsShrews emit series of ultrasonic squeaks.
Unlike those of most bats, these are low amplitude, and
frequency modulated.

They contain no 'echolocation clicks' with reverberations and
would seem to be used for simple, close range spatial
orientation.

In contrast to bats, shrews use echolocation only to investigate
their habitat rather than additionally to pinpoint food
Order: Macroscelidea (elephant shrews or sengis)
• long, flexible snout, large eyes and long ears.
• elephant-shrews inhabit habitats of central and southern
Africa.
• they even can be found in the Namib desert, one of the
driest regions of the earth.
Elephant Shrew TerritoriesElephant-shrews live in pairs and defend territories.
Females drive away other females while males try to ward off
other males.

Although they live in pairs, the partners don't care much for each other and their sole purpose of associating with the opposite sex is for reproduction.

Social behaviors are not very common and they even have
separate nests. They generally have one or two precocial young.

These animals meticulously maintain trails systems for foraging and protection.
Difference between elephant shrews and "insectivores"
• have auditory bullae
• have zygomatic arches
• olfactory lobes of the brain are small
• has a cecum
• rat- to mouse-sized (50-400 g)
• large eyes, large ears
• long, mobile snout
• they have high-crowned cheek teeth (hypsodont)
• molars are quadrate and dilambdodont.
• elephant-shrews eat mainly invertebrates, such as insects, spiders,
centipedes, millipedes, and earthworms
Shrews and the Weather
During hot weather these animals become nocturnal to avoid theheat and thereby reduce energy needs and water losses.

During cold periods, they undergo periods of torpor where they
allow their body temperature to 5°C and where metabolic rate
drops to 2% of normal.
Giant Elephant Shrew
2008: new "giant" elephant shrew (sengi) - 750g
• isolated mountains Kenya/Tanzania
• first new species of elephant shrew in 126 years
Order: Scandentia (tree-shrews)
two families:
• Tupaiidae, the treeshrews (3, 18)
• Ptilocercidae, the pen-tailed treeshrew (1, 1)
For a long time, treeshrews were considered part of the Order
Insectivora.

Treeshrews were then moved from Insectivora to the Primates,
because of certain internal similarities, and were classified as a
primitive prosimians (Strepsirhini - lemurs etc).
How do tree shrews resemble primates
• have a large braincase
• have a postorbital bar
• have scrotal testes
• similar structure of carotid and subclavian arteries
• tribosphenic molars
• unperforated palate
• lower incisors are procumbent and used for grooming
Family: Ptilocercidae
Order: Scandentia (tree-shrews)
The Malaysian pen-tailed treeshrew is one of a small group of wild mammals that chronically consume alcohol
Tree Shrews and Alcohol
A study of the treeshrew in Malaysia found that it spends several hours/day consuming the equivalent of 10 to 12 glasses of wine with an alcohol content of up to 3.8%. Drinking naturally-fermented nectar of the bertam palm.

Despite consuming relatively large amounts of alcohol, the pen-tailed treeshrew does not become intoxicated. Measurements of a biomarker of ethanol breakdown suggest that they may be metabolizing it by a pathway that is not used by humans.
Family Tupaiidae
Order: Scandentia (tree-shrews)
Tupaiid treeshrews are slender animals with long tails and soft,
grayish to reddish-brown fur.

The terrestrial species tend to be larger than the arboreal forms, and to have larger claws, which they use for digging up insect prey.
Tree Shrew Feeding Habits They are omnivorous, feeding on insects, small vertebrates, fruit, and seeds.
Tree Shrew Teeth
They have poorly developed canine teeth and
unspecialized tribosphenic molars. Their upper molars are
dilambdodont.
The lower incisors are procumbent and are used for
grooming. Treeshrews' skulls are broad due to the large
protruding, sideways facing orbital cavities
Tree Shrew Sight Treeshrews have good vision, which is binocular in the case of
the more arboreal species
Tree Shrew Living Arrangement These animals live in small family groups, which defend their
territory from intruders. They mark their territories using
various scent glands, or urine, depending on the particular
species.
Order: Dermoptera
(flying lemurs or colugos) • In the past, these have been classified with bats, primates, and insectivores.
• There is 1 family (Cynocephalidae), 2 genera (Cynocephalus
and Galeopterus) each with 1 species
Most distinct feature of Dermoptera Their most distinctive feature is the membrane of skin that extends between their limbs and gives them the ability to glide long distances between trees
Colugos Body They have a patagium

Even the spaces between the fingers and toes are webbed to increase the
total surface area.

They have a keeled sternum.
Colugos in Philippines
Cynocephalus volans occurs in
the Philippines
weigh up to 2 kg, and can glide at up to 25m/s which is very
fast for a glider
Colugos Eating Habits These are herbivores, eating mostly leaves, shoots, flowers and sap, and probably fruit as well. They have well-developed ceca (4x body length) and intestines (9x body length), capable of extracting
nutrients from leaves. They are very specialized arboreal folivores, with long gut retention times.
Why are Colugos Clumsy ClimbersLacking opposable thumbs and not being especially strong, they proceed upwards in a series of slow hops, gripping onto the bark of trees with their small, sharp claws. They are as comfortable hanging underneath a branch as sitting on top of it. In the air, however, they are very
capable, and can glide as far as 70 meters (230 feet) from one
tree to another with minimal loss of height
Colugos Teeth
• They have procumbent lower incisors.
• The incisor teeth of colugos are highly distinctive; they are
comb-like in shape (pectinate), with up to twenty tines on each
tooth. The second upper incisors have two roots, another unique feature among mammals
Culogos Gestation
The young are born after 60 days of gestation in a tiny and
undeveloped form, and spend their first six months or so of life
clinging to the mother's belly. To protect them and transport them she curls her tail up to fold the gliding membrane into a warm, secure quasi-pouch. Breeding is fairly slow as the young do not reach full size until they are two or three years old
Colugos In Malay, Sumatra etc
Galeopterus variegatus
occurs in Malaya, Sumatra, Java, Borneo, and nearby islands.
weigh up to 2 kg, and can glide at up to 25m/s which is very
fast for a glider.

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