BEAVERS ARE LARGE AQUATIC MAMMALS
BEAVERS ARE BELIEVED TO BE RODENTS
BEAVERS HAVE ALL THE CRITERIA TO BE RODENTS
2 MATCHING PAIRS OF INCISORS AT FRONT OF JAWS
GAP ON SIDES OF INCISORS
OVER SIZED MUSCLES IN MOUTH TO AID IN GNAWING
THERE ARE 2,000 KNOWN SPECIES OF RODENTS IN THE WORLD
AT LEASE 40 % OF ALL KNOWN MAMMALS ARE RODENTS
ONE OF SMALLEST RODENTS
EURASIAN HARVEST MOUSE
.14 OF ONE OUNCE
( .50 is 1/2 .. half of the ounce -- .25 is 1/4 .. quarter of the ounce -- .14 is a little more than 1/8 .. eighth of the ounce )
SOUTH AMERICAN CAPYBARA
MORE THAN 100 POUNDS
BEAVERS ARE THE 2ND LARGEST RODENT IN THE WORLD
BEAVERS ARE THE LARGEST RODENT IN NORTH AMERICA
THERE ARE 2 SPECIES OF BEAVER IN THE WORLD
1 IN NORTH AMERICA
1 IN EUROPE
beavers can be all sorts of colors
brown .. dark brown .. red .. golden .. black .. white .. silver .. albino
most beavers are usually brown in color
both male are female have same body coloration
25 - 30 inches long not including tail
45 - 90 pounds
can weigh up to 100 pounds
shaped like a seal
body shape helps the beaver to move fast in the water !
thick thick thick
looks black when wet
2 kinds of fur
short soft underfur
lighter in color - grey
inner coat hairs have tiny scales on shafts .. scales cling to each other .. create air pockets
traps air and keeps it close to skin for warmth .. even in icy water
keeps them comfortable in water
long heavy outer guard hairs on top of underfur
guard hairs define the color of the beaver
shed outer coat every year
rounded head shape
reduces drag in water ( drag is the force of resistance against the beaver as it moves through the water )
great vision .. super great at close distances
3 eyelids on each eye
2 outer lids close when blinking and sleeping
1 inner lid slides across over eye .. from inside corner outward to outer corner of eye ..
transparent .. called nictitating membrane .. protects eyes underwater and when cutting wood
NATURE'S OWN SAFETY GOGGLES !!!
super excellent hearing
detect sounds in air and water
have skin flap valve in each ear .. closes underwater .. keeps water out .. lets sound in
area around velvety
super excellent sense of smell
nose has internal skin flap valves .. keeps water out of nose when underwater
beaver's 4 inch incisor teeth are located in front of lips .. only about 1" is visible above the gum line
lips very furry
lips have flap that closes behind incisors .. their lips are divided in the middle ..
this is how beavers can hold wood in their mouths underwater
and not get water into mouths at same time
large powerful jaws
beavers have special adaptation to eat and breathe at same time
separate passage from nose to lungs
separate passage from mouth to esophagus
so they can chew and swallow at same time as breathing
both actions are completely separate
all of this is to keep water out of lungs
use super amazing and strong teeth as tools
front incisors grow throughout life
used to cut and gnaw trees
in just a couple of minutes a beaver can gnaw through a tree trunk with a 6 inch diameter !
super sharp front teeth also used as weapons of self defense
grinding teeth on sides of mouth to chew
these cheek molar teeth do not grow in the same way
as the incisor front teeth do ..
cementum is added to surface of the enamel of the cheek teeth continually and that strengthens those teeth
adult beavers have 20 teeth
10 teeth in each jaw
orange layer on front teeth is super hard enamel - iron in their teeth gives orange color and super strength
FRONT PAW HANDS
front paws are very dexterous
3 inches long
3 inches wide
look like small human hands
first finger acts like opposable thumb to grip
claws 1 inch long
sometimes when swim
make tight fists with front paws and hold arms and paws close to chest against chest
BACK PAW FEET
7 inches long
5 inches wide
very long toes
5 toes on each foot
claw nails shorter than on front paws
4 single claws on each foot
1 split claw on each foot - 2nd toe in from inside of each foot - like the 2nd toe on human foot next to big toe
split claw has slit in middle
used as comb to clean fur
strong durable claws
back feet used for excavation
back feet used like flippers when swim
2 glands called castor glands
secrete strong smelling liquid called castoreum
located near base of tail
both male and female have these glands
secrete castoreum through skin ..
use castoreum as grooming agent for fur ..
beavers bring tail forward under body and sit on tail
then collect oil in front paws and spread through fur
oil keeps fur waterproof
groom their fur everyday
used like rudder when swimming
continues to grow entire lifetime .. in length and width .. not a lot .. but it really does grow !!!
body fur covers about 1/4 of tail
rest of tail has few sparse hairs
tail has leathery dark skin
tail has scale shaped PATTERN of ridges
BEAVER TAIL DOES NOT HAVE SCALES ! ! !
tail helps control body temperature ..
if beaver too hot .. heat will radiate out of tail to cool beaver
if temperature outside too cold .. tail will hold heat in
network of blood vessels in tail is how body temperature is regulated
when blood vessels dilate .. heat goes out
when blood vessels constrict .. heat stays in
uses tail as prop for support when beaver ..
stands up to eat bark from tree
when cut tree
when walking upright
use tail as communication tool
BEAVER TAIL IS USED FOR CONSTRUCTION ! ! ! but not as a trowel .. is used as a support device
caudal vertebrae that run down middle of tail are extension of spine
fat stored in tail .. so tail can become whole lot thicker
when food is scarce the tail fat is used as source of nutrients that the body draws upon
super fantastic swimmers
only whales and seals are better swimmers
beavers swim 6 miles per hour
beavers have a valve called the cloaca that keeps water out of ano-urinogenital openings
( these are the openings for the elimination of digestive wastes and for reproduction )
beaver can travel 1/2 mile before surfacing for air
when the outside temperature is cold ..
before beavers go into the water they raise their body temperature by about 1- 2 degrees Fahrenheit
this keeps them warm in very cold water
when dive into water heart rate slows .. so use less oxygen
when breathe .. at least 75% of air in lungs is exchanged for new and fresh air
humans exchange 10 - 15 % of air in lungs
BEAVERS ARE SUCH AMAZING ANIMALS !
just their physical characteristics alone are incredible !!!
but the things that they DO are even more amazing !!!!
the length of a straight line
through the center of an object
from one side edge to the other side edge
THE NORTH AMERICAN BEAVER LIVES UP TO 20 YEARS !
WHERE IN THE WORLD
BEAVERS LIVE ALL OVER NORTH AMERICA
NORTH AMERICA TO ARCTIC EDGE
SOUTH TO NORTHERN MEXICO
EXTREME NORTH OF MIDDLE CANADA
MOST OF NEVADA
MOST OF ARIZONA
SOUTHERN PENINSULA PART OF FLORIDA
COASTAL PANHANDLE PART OF FLORIDA
MISSISSIPPI DELTA REGION (their range ends 50 - 100 miles from the shore)
BEAVERS ARE SO INTELLIGENT THAT THEY KNOW TO AVOID THE HURRICANE ZONE !!!
NO BEAVER WOULD BUILD IN THE HURRICANE ZONE ..
THEY ARE SO AMAZING !!!!
elevations from sea level to 10,000 feet
prefer slow moving
need water source to be within nearby woodlands
prefer abundance of aspen trees
can use small creeks .. all the way up to large rivers .. including the MISSISSIPPI RIVER
the territory of a CLAN of beavers is between 10 - 75 acres
BEAVERS MAY TRAVEL 1/2 MILE AWAY FOR FOOD OR BUILDING MATERIALS IF THEY NEED TO
THE AREA IN WHICH BEAVERS WILL GET FOOD SUPPLIES AND BUILDING SUPPLIES
IS WITHIN A FEW HUNDRED YARDS ( usually within 300 yards ) OF THEIR LODGE
BEAVERS ACTUALLY CONSTRUCT THEIR HABITAT !!!
THERE ARE SEVERAL SPECIFIC STEPS OR STAGES THAT BEAVERS HAVE TO ACCOMPLISH TO COMPLETE
CONSTRUCTION OF THEIR HABITAT
1. SCOUT FOR NEW HOME BUILDING SITE
2. GATHER CONSTRUCTION BUILDING MATERIALS
3. CONSTRUCT DAM / CREATE POND
4. CONSTRUCT BANK DEN
5. CREATE TRAILS
6. CREATE CANALS / CHANNELS AND LOCKS
7. CREATE TUNNELS
8. CONSTRUCT LODGE
first they scout out just the right place .. slow water .. plenty of good trees that they like right around the water
if lake .. do not need dam ..
usually only dam if .. river .. stream .. lake outlet ..
BEAVERS BUILD DAMS SO THEY CAN CREATE
THEIR BEAVER POND HABITAT
THEIR LODGE HOME IN THE MIDDLE OF THEIR CREATED BEAVER POND
how build ..
usually select site for dam that is downhill from food sources and building material sources
build at shallow point of water source - in center of area to dam - build outward on each side towards banks
mud stones piled up on water bottom .. in middle of water ..
add poles - poles are pushed down into the water bottom
poles go in with tips leaning in same direction that water is flowing
pack with more mud and stones ..
bring from water bottom with paws holding the mud and stones close to chest
also adding brush and twigs ..
top of dam above water
can be 1,000 feet long ! ! !
sometimes more than one beaver family works on dam
materials used ..
usually begin with willows
use lots of alders
(bark has been peeled off of all construction pieces)
(weighing up to 40 pounds)
beavers wil add all sorts of found items ..
cans . bottles . balls . tires . cups . corn stalks .
DAM FACTS ..
2 beavers can build small dam in 24 hours
large dam in 3 - 4 nights
water rises behind dam 3 - 7 feet
a tiny current of water goes over the central outlet of the dam
there are spaces underwater where fish can go through
typical dam 75 feet long
5 feet wide
2 - 10 feet tall
use hundreds of saplings to construct
flat on top
all sorts of animals use like bridge
one of biggest dams in world is on the BOW RIVER in SASKATCHEWAN CANADA
5,000 feet long .. almost 1 mile ! ! ! wow !!!!!
largest dam in the United States is on the JEFFERSON RIVER in MONTANA
2,300 feet long ! ! !
this dam is so strong that a human on horseback could ride across it !!!
dams used and repaired for many years .. some are HUNDREDS of years old !!!
FEMALE BEAVER IS THE DOMINANT BEAVER OF THE CLAN
she directs the construction
the females of the clan do most of the actual construction
BEAVER DAMS ARE SO COMPLEX - NO HUMAN ENGINEER COULD DUPLICATE ! !
dams are not watertight ... underwater there are openings ..
a steady flow of water continues to travel through
beavers do not interfere with fish spawning runs ..
even large salmon and trout get through the openings and travel upstream to spawn
if damage to dam .. beavers immediately respond and repair damage
will even come out during day to fix !
beavers build larger constructions than any animals in North America ..
beavers tether all sorts of sticks and branches close to dam to be used as repair materials
so they can make immediate repairs !
beavers do not like gushing water .. they will try to stop it up !!!
new dams easy to notice ..
old dams NOT .. well camouflaged because all sorts of plants grow on them ..
birds drop seeds and they sprout and grow ..
cut construction branches take root and sprout and grow !
most dam work is done in fall .. to get SUPER ready for winter !
built in bank of river stream creek
build at same time build dam so they can get to safety until lodge is finished
then use the dens as secondary lodges for safety
dig out den .. dig an entrance / exit below surface of water
sometimes pile sticks twigs branches mud on top for safety - also camouflages their air vents
inside bank den .. same size as lodge inside
can use only a bank den if river is large and fast moving
also called hut or hut lodge
make trails from water edge up into forest
nip and trim the plants shrubs to keep trails clean
about 15 - 20 inches wide
may be 100 yards
go to feeding areas - where they cut down small trees and bring the trees to the water to eat
CANALS / CHANNEL and LOCKS / MINI DAMS
beavers build all sorts of structures to
control water flow
control water level
channels act as drainage ditch if water level of pond gets too high
move logs down to pond
channel system moves logs easily to where they are needed
12 - 18 inches deep
18 - 24 inches wide
may be 700 feet or more long
make safety tunnels so they can stay in water as much as possible while moving from place to place
make tunnels from tree supply areas to pond
created as result of building dam
created on the upstream side of the dam
pond is really ..
safe water travel route to food
safe water travel route to building materials
saves time for beavers too !!
faster in water than on land !!
as beavers use mud for the dam and lodge construction they dig out the bottom of the pond area
this makes the pond area deeper !
pond must be at least 3 feet deep for lodge building to begin
usually ponds are about 4 - 6 feet deep
POND FACTS ..
winter .. pond freezes .. sometimes ice layer 2 feet thick .. no predators can get to lodge ..
water level of area around pond rises after pond is created ..
so .. the entire area is more resistant to FIRE ! WOW !!!!
takes about 6 months to build at leisurely pace
can complete in 30 days if rushed by oncoming winter
4 - 8 feet diameter
3 - 4 feet height
floor 4 - 6 inches above water
2 underwater entrances / exits ..
1 to pull in timber and supplies
1 for beavers to go in and out
top of lodge is woven thatch
vent holes between branches in ceiling to let in fresh air
but constructed at angles in such a way .. no rain or snow gets in !! !
walls 10 inches thick
plaster with mud inside
freezes hard and solid
all smooth inside
looks like a tepee
usually 3 - 6 feet above water
beavers live inside these complex structures as their homes
sometimes in middle of pond
like island in middle of pond
most often build on north or northwest side of pond
building there allows for more sun .. and faster melting of ice in spring
build lodges so they will have a permanent home in which to ..
stay warm and dry
raise their families
materials used ..
logs .. large tree wood - 4 - 5 feet lengths
( willow and alder .. the best )
stones ( up to 40 pounds ) WOW !!!
add all sorts of things to lodges
cans . bottles . tires . balls . cups . corn stalks
how build ..
use peeled sticks ..
build platform to support internal chambers
put log poles into pond bottom - dig out holes for log poles to be inserted
lay more sticks into those - across
pack with .. mud .. leaves .. rocks ..
layer with more sticks twigs
repeat until platform top layer is above water
flatten top layer
this top layer will become floor inside lodge
lighter layer of brush sticks small logs piled on creates dome shape above water
beavers nip and cut and trim branches to create tunnel entrances / exits
then beavers excavate 2 tunnels through mud underwater up into lodge mound
chew out chamber inside mound
chamber becomes beaver's living areas
create second floor sleeping chamber .. with .. mud .. sticks .. leaves
walls of tunnels and chambers are plastered smooth with mud and leaves and twigs
do not plaster very top of chamber
this allows for ventilation
LODGE FACTS ..
carry mud rocks vegetation in front paws while walking upright with partial support from tails
may build summer lodge and winter lodge
lodge usually 20 feet along bottom of pond
usually 10 feet from pond bottom to top lodge dome
6 - 11 feet across above water
3 - 6 feet tall above water
external lodge wall very very thick and strong !
first level inside 3 - 5 inches above water -- for eating -- grooming
second level quite a bit higher -- for sleeping
so warm inside .. in winter .. that steam rises from ventilation holes - looks like they have a fireplace !
always repairing .. take super great care of lodge !
use bedding in sleeping chamber
finely shredded soft strips of wood
every day replace their used bedding with FRESH BEDDING !!!
more sanitary than many many many humans !!
beavers used to build HUGE multi-family lodges
with as many as 30 families in one colony
each family had a separate lodge apartment
all of these apartments were attached to each other !!
creating HUGE HUGE HUGE lodges !!!!
built these until European colonists came to North America
beavers changed then to smaller lodges for safety ...
less obvious to super dangerous dangerous dangerous humans ..
more easily camouflaged ..
TO CUT A TREE
beaver stands on hind legs .. uses tail for support .. places front paws on trunk ..
turns head sideways ..
bites trunk .. makes cut .. then .. bites trunk further down towards ground ..
bite marks are always two together .. about 7/8 wide or wider ..
distance between two bites depends on size of tree ..
big tree .. first two bite cuts are further apart
small tree .. first two bites are close to each other .. about 3 inches apart
bites a few more times to the two original bites to make deeper
pulls off wood between with teeth .. and repeats process ..
around base of tree collects pile of wood chips !
usually cuts and tears wood all around trunk until it falls ..
or may just cut and tear from one side until close to falling ..
push with head nose feet shoulder ... push .. usually falls towards water ! ! !
gravity takes over and CRACK !!!! CRASH !!!! and down it falls !!!
both tree and trunk stump that will remain are gnawed to a point ..
beaver usually jumps into water as tree falls ..
and then ..
makes sure no predator was attracted by noise ..
goes to work on fallen tree ..
gnaws off branches .. carries pushes pulls rolls cut logs into water
usually one beaver does this job alone ..
others working on other projects
You satisfy every living thing. "