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It is not the strongest of the
species that survive, nor the
most intelligent, but the one
most responsive to change.
- Charles Darwin
Chapter 22 Mammals
• What is a mammal?
• There are 6 things to consider when asked
if an animal is a mammal.
• Character One
• The first characteristic that guarantees that an animal is a mammal
is that it (if it is female) can produce milk to feed its young. This milk
is produced by modified sweat glands called 'mammary' glands. It is
from these glands that the whole group takes its name, 'Mammals.
What is a mammal?
• Character Two
• The second test is the possession of hair, something humans often
have problems with but which they should respect more. No other
animal has hair in the same form as mammals, and all mammals
have some hair at least at the beginning of their lives - baby whales
and dolphins are born with a moustache.
• Character Three
•
The lower jaw in mammals is a single bone on either side. In all
other vertebrates there are more than one bone on each side of the
jaw.
• Character Four
•
The mammal middle ear, and only the mammal middle
ear, contains 3 bones. The Stapes or (Stirrup), Incus or
(Anvil) and the Malleus or (Hammer). Once these bones
were part of the lower jaw, but during the early evolution
of mammals they changed jobs and became a part of
our hearing apparatus instead.
What is a mammal?
• Character Five
In mammals the main artery leaving the heart curves to
the left becoming the aortic arch. In birds it curves to the
right and in all other vertebrates there are more than one
main artery leaving the heart.
•
• Character Six
• Finally mammals
have
amammal?
diaphragm. A sheet of
What
is
a
muscle and tendon that separates the body
cavity into two sections. Heart and lungs
before/above, liver, kidneys, stomach, intestines,
etc, behind/below. No other animal has a
diaphragm.
• There are about 4260 named species of
mammal in the world. I say about, because it is
hard to get a list of species that all the experts
agree on. So until you become an expert
taxonomist and can solve the problems of what
are or are not species, 4260 will do for 2000 AD,
but more will be discovered.
Introduction
• Mammals are the dominant life form on this
planet at the moment, at least from a human
perspective.
• There are about 4260 species of mammals
known on this planet at the moment, though
taxonomists are still arguing.
• Mammals are not the largest animal group on
the planet, three other groups of vertebrates outnumber them at the moment, Reptiles 6787
species, Birds 9703 species and Fishes with
approximately 28000 species.
General Info
• Mammals are friendly or fierce, cuddly, cute
and/or awesome depending on which ones you
look at. They fascinate and horrify us. We eat
them, ride them, keep them as pets, makes
clothes out of them, hunt other mammals with
them and use them as substitutes for ourselves
in scientific, particularly medical, research. We
use them to carry our burdens, support our
foolish habits (gambling) and expect them to
entertain us. To most people animals are
mammals.
Did you Know??
• Nearly a quarter of all mammals can fly. Yes, it's true,
with a huge 985 species bats make up 23.1% of all
known mammals by species.
• The meek shall inherit the earth, or at least Australia
which is a reasonable portion of it. With about 147 million
head of sheep, there are about 8 to 9 sheep for every
person in Australia.
• A prehistoric mammal, the extinct Irish Elk, Megaloceros
giganteus, had the largest antlers ever. A specimen
found in an Irish peat bog had antlers 4.3 m or 14 ft
across which weighed 45kg or 100 lbs.
• The Giant Anteater, Myrmecophaga tridactyla, eats over
10,000,000 ants or termites a year.
• No two Giraffes have the same pattern of spots and no
two Zebras have the same pattern of stripes.
Did you Know??
• Whales and dolphins sleep one side of their brains at a
time - while one side is asleep the other keeps watch for
danger.
• Sperm whales can stay submerged for up to two hours
descending over a mile below the surface.
• The Andes Fishing Mouse was first recorded for science
when scientists from the British Mammal Society
watching a television programme on the 'Wildlife of the
Andes' saw a specimen in the programme and realised
that no records of it existed.
• House mice, Mus musculus, have on several occasions
been so numerous that they had a population density of
over 200,000 per hectare,that's 2 mice for every square
metre of land if they were all spaced out evenly.
Did you Know??
• Rodents, at least the few species that are pests, cost us about £43
million tonnes of damaged and destroyed food every year.
• There is a vine in Madagascar that is pollinated exclusively by
lemurs.
• Chimpanzees can go bald as they age.
• A female kangaroo can produce 2 different kinds of milk at the same
time when she is suckling youngsters of different ages.
• Anteaters are the only mammals to have no teeth.
• Hippopotamuses produce a special reddish oil from modified sweat
glands that acts like a sun-cream to stop them getting sunburned.
• Shrews evolved 54 million years ago, today some species have
such fast metabolisms that they need to eat up to 1.3 times their
own weight in food everyday.
Skeleton of a Mammal
Start of Day 2
External Structure and Locomotion
page 347
• The first structure we need to examine is
the skin of a mammal.
• Functions: to protect from mechanical
injury, invasion by microorganisms, the
suns ultraviolet rays, regulates body
temperature, sensory perception,
excretion, and water regulation.
External Structure and Locomotion
page 347
• The second structure is Hair.
• Facts: hair is composed
mostly of dead cells, it is
periodically molted
• Functions: as insulation,
camouflage, the sense of
touch.
External Structure and Locomotion
page 347
• The third is claws.
• Functions: used for movement, offensive
and defensive behavior
• (can be nails more like humans or hooves)
Specialized Glands
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1. sebaceous glands
2. sudoriferous glands
3. Scent or musk glands
4. mammary glands
Specialized Glands
• sebaceous glands
• Work with the hair follicles.
• Produce/secrete an oily substance that
lubricates and waterproofs the skin and
hair.
• sudoriferous glands
• The small glands- These release watery
secretions used in evaporative cooling.
Specialized Glands
• The large glands- secrete a mixture of salt, urea,
and water which the microorganisms then
convert into a odorous product. (smell)
• Scent or Musk Glands• These are found around the face, feet or anus of
many mammals.
• These secrete pheromones which are involved
with defense, sex recognition, and territorial
behavior.
Specialized Glands
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Mammary glandsFunctional in the female
Present but not functional in the male
The milk that they secrete contains water,
carbohydrates, fat, protein, minerals, and
antibodies.
So bone structure and locomotion
leave what behind???
• Tracks
What is the significance of a track?
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Tracks can be used for many things:
1. identifying the animal
2. tracking an animal in a hunt
3. searching for a lost animal
4. mammals may follow the tracks of
others for both mating and predatory type
actions.
• 5. scientific research
How do tracks form?
• 1st: you must have the correct ground conditions
for a track to be created.
• The ground must be moist so that the
impression can be made.
• Second the animal must be heavy enough in
combination with ground conditions to make an
impression.
• Thirdly The following conditions after an
impression is made must be such so that
impression stays in tact and is not disturbed.
So, Let’s give track making a try??
• You will need a writing utensil
• In just a moment you will go into the lab and find the
station that has a piece of paper at it with your name on
it.
• Second you will check to see that you have a dissecting
pan, blank piece of paper, two containers of play dough,
and a track.
• Thirdly on my signal you will mash out the play dough
flat and try with your fingers to make the impression
matching the paper copy you found at your station.
• Fourthly on my signal you will again work on the track
but this time you can use other objects other than your
hand to make the track.
After tracking making….
• Following track making we will again play
our vocabulary flashcard game. You will
have 30 seconds at each station the
stationary person at the station will write
down your name and whether or not you
got the question correct. When time is
called you will move to the next station
and repeat. The person that gets the most
correct will win reward.
After vocabulary flashcards…
• Our last activity will be a matching game.
• Half the class will get a card with a picture
on it and the other half a card with a word
on it.
• You will have to wonder the room to find
the matches.
Forms of Learned Behaviors
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Associative learning
Classical conditioning
Operant conditioning
Observational learning or modeling
Insight learning
Associative Learning
• Where an animal learns to associate one
stimulus with another.
• 2 forms:
• 1. classical conditioning: example: rubbing
meat powder on dogs gums for several
days, and then doing that plus ringing a
bell. Both made the dog produce salvia
and become hungry.
Associative Learning Continued
• 2. operant conditioning: when an animal
learns how do something because there is
a treat or reward. Example: an animal
learns to press a lever and get food out of
a machine.
Observational Learning or
Modeling
• When an animal learns a
behavior from watching
other animals conducting
that behavior
• Example: an animal
learning to hunt in a pack
Insight learning
• This is the highest form of learning. This is
the ability to solve problems.
• Example: (from the video) The monkeys
stacking up boxes to reach a banana. Or
the squirrel going through the obstacle
course to reach food.
Nature vs Nuture
• Nature is the way that things happen within mother earth without
human intervention.
• Nuture- is where an animal cares for another.
• One type is Imprinting- this happens when young mammals are in
contact with another non-related species shortly after birth. They
model the non-related species in eating, behavior such as eating and
aggression. This is usually irreversible.
• Example would be the Goslings that imprinted with humans instead
of other geese.
Additional things in the behavior
note section
Behaviors
1. aggression- any sign of frustration
Examples: hair standing on end, showing of the
teeth, growling or making a defensive noise
2. territoriality- behavior in which an animal
attempts to mark his or her environment as
there own.
Examples; urinating on things, expelling feces,
expelling pheromones, leaving claw marks etc
on trees, mating
Nutrition and Digestive System
• Very similar to that of other
vertebrates
• Has specializations for
different feeding habits
• We have herbivores,
carnivores, omnivores
• A specialization of the
digestive tract for our
herbivores is an enlarged
cecum for the digestion of
cellulose.
Nutrition and Digestive System
• The cecum is a digestive or fermentation
pouch where microorganisms aid in
cellulose digestion
• Our ruminant mammals have four
chamber stomachs, to help in digestion.
Winter Sleep and Hibernation
• Mammals react in different ways to
environmental situations
• Winter sleep is a period of time when they
become less active but are still relatively alert
and easily aroused.
• Hibernation is a period of winter inactivity in
which the hypothalamus of the brain slows the
metabolic, heart, and respiratory rates. Prior to
hibernation animals acquire large quantities of
body fat. The body's temperature is at 2
degrees Celsius during this time.
Reproduction
• 1. starts with a specific time during the year
when ova are capable of being fertilized.
• 2. climatic conditions must be in favor of
successful development
• 3. Estrus happens next and can happen in
accord with number one. Estrus is a time when
the female is behaviorally and physiologically
receptive to the male. When the egg is available
and can be fertilized.
Gestation Periods for Different
Mammals
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Killer Whale- 15-18 months
Swine- warthog- 170-175 days
Cat- 63-65 days
Dog- 56-72 days
Cow- 283 days
Horse- 320 days
Rat- 21 days
Rabbit- 27-36 days
Elephant- 2 years