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On this page we start out with the seals and sea-lions and a few other
interesting sea-animals to be found
in coastal waters of USA and Canada, including Alaska and the Aleutean
Islands.
Marine Mammals
Creator: Hines, Bob
Read about the
seals on Surtsey Island - the new volcanic island near Iceland
Northern
fur seal, Callorhinus ursinus
Northern
fur seal Bogoslof Island, Callorhinus ursinus
Photo:
Morkill Anne
|
The northern fur seal, Callorhinus ursinus, is an
eared seal found along the north Pacific Ocean, the Bering
Sea and the Sea
of Okhotsk. It is the largest member of the fur seal subfamily,
Arctocephalinae, and the only species in the genus Callorhinus.
The northern fur seal is found in the north Pacific
its southernmost reach is a line that runs roughly from
the southern tip of
Japan to the southern tip of the Baja California Peninsula,
the Sea of Okhotsk and the Bering Sea. There are estimated
to
be around 1.1 million northern fur seals across the range,
of which roughly half breed on the Pribilof Islands in the
east
Bering Sea. Another 200250,000 breed on the Commander
Islands in the west Bering Sea, some 100,000 breed on
Tyuleni Island off the coast of Sakhalin in the southwest
Sea of Okhotsk, and another 6070,000 in the central
Kuril Islands
in Russia. Smaller rookeries (around 5,000 animals) are
found on Bogoslof Island in the Aleutian Chain and San Miguel
Island in the Channel Island group off the coast of California.
Northern
fur seal - overview
©
BBC Natural History Unit
www.arkive.org
|
During the winter months, northern fur seals display a
net movement southward, with animals from Russian rookeries
regularly entering Japanese and Korean waters in the Sea
of Japan and Alaskan animals moving along the central and
eastern Pacific as far as Baja California.
The northern fur seal's range overlaps almost exactly with
that of Steller sea lions, with which they occasionally
cohabit reproductive rookeries, notably in the Kurils, the
Commander Islands and and Tyuleni Island. The only other
fur seal found
in the Northern Hemisphere is the Guadalupe fur seal which
overlaps slightly with the northern fur seal's range in
California.
|
Northern
fur seal, mature bull, Callorhinus ursinus
|
Northern fur seals have extreme sexual dimorphism,
with males being 3040% longer and more than 4.5 times
heavier than
adult females. The pelage is thick and luxuriant, with a dense
underfur that is a creamy color. The underfur is obscured
by
the longer guard hairs, although it is partially visible when
the animals are wet. Features of both fore and hindflippers
are
unique and diagnostic of the species. Fur is absent on the
top of the foreflippers and there is an abrupt "clean
line" across the
wrist where the fur ends. The hindflippers are proportionately
the longest in any otariid because of extremely long, cartilaginous
extensions on all of the toes.
Males can be as large as 2.1 m and 270 kg. Females can be
up to 1.5 m and 50 kg or more. Newborns weigh 5.46 kg,
and are 6065 cm long.
The teeth are haplodont, i.e. sharp, conical and mostly single-rooted,
as is common with carnivorous marine mammals
adapted to tearing fish flesh. As with most caniforms, the
upper canines are prominent. |
St.
Paul Island Fur seal rookery, Pribilofs, Alaska
Photo:
Angell, Bob
|
Fur seals are opportunistic feeders, primarily feeding on
pelagic fish and squid depending on local availability. Identified
fish
prey include hake, herring, lantern fish, capelin, pollock
and mackerel. Their feeding behavior is primarily solitary.
Northern fur seals are preyed upon primarily by sharks and
orcas. Occasionally, very young animals will be eaten by
Steller sea lions. Occasional predation on live pups by arctic
foxes has also been observed.
Due to very high densities of pups on reproductive rookeries
and the early age at which mothers begin their foraging trips,
mortality can be relatively high. Consequently, pup carcasses
are important in enriching the diet of many scavengers,
in particular gulls and arctic
foxes
|
Text
about the Northern Fur Seal: http://en.wikipedia.org/wiki/Northern_fur_seal
|
Gray
Seal, Halichoerus grypus
Large
group of gray seals, Halichoerus grypus, on beach at
Monomoy National Wildlife Refuge, Cape Cod, MA
Photo: Shannon, Keith
|
The grey seal, Halichoerus grypus, meaning
"hooked-nosed sea pig", is found on both shores of
the North Atlantic Ocean.
It is a large seal of the family Phocidae or "true seals".
It is the only species classified in the genus Halichoerus.
Its name is spelled gray seal in the US; it is also known as
Atlantic grey seal and the horsehead seal.
In Great Britain and Ireland, the grey seal breeds in several
colonies on and around the coasts. In the Western North
Atlantic, the grey seal is typically found in large numbers
in the coastal waters of Canada and south to about New Jersey
in the United States. In Canada, it is typically seen in areas
such as the Gulf of St. Lawrence, Newfoundland, the Maritimes,
and Quebec. The largest colony in the world is at Sable Island,
NS. In the United States it's found year round off the
coast of New England, in particular Maine and Massachusetts,
and slightly less frequently in the Middle Atlantic States.
Its natural range extends south to Virginia.
During the winter months grey seals can be seen hauled out on
the rocks, islands, and shoals not far from shore, and
occasionally coming ashore to rest. In the spring the recently
weaned pups and yearlings occasionally strand on beaches
after becoming "lost." |
Grey
seal hunting and feeding
Video:
Saint Thomas Productions, Audio: Master Tracks
www.arkive.org
|
It is a large seal, with the bulls reaching 2.53.3 m
long and weighing 170310 kg; the cows are much smaller,
typically
1.62.0 m long and 100190 kg in weight. Individuals
from the western Atlantic are often much larger, with males
reaching
400 kg and females weighing up to 250 kg. It is distinguished
from the harbor seal by its straight head profile with nostrils
that
are well apart, and fewer spots on its body. Bull Greys have
larger noses and a more convex profile than common seal bulls.
Males are generally darker than females, with lighter patches
and often scarring around the neck. Females are silver grey
to
brown with dark patches.
The grey seal feeds on a wide variety of fish, mostly benthic
or demersal species, taken at depths down to 70 mor more.
Sand eels, Ammodytes spp, are important in its diet in many
localities. Cod and other gadids, flatfish, herring and skates
are also important locally. However, it is clear that the grey
seal will eat whatever is available, including octopus (see
video)
and lobsters. The average daily food requirement is estimated
to be 5 kg , though the seal does not feed every day and it
fasts during the breeding season. |
Grey
seal colonies
Video: Granada
Wild & Green Umbrella Ltd.
Audio: Master Tracks, Granada Wild & Natural FX
www.arkive.org
|
The pups are born in autumn (September to November) in the
eastern Atlantic and in winter (January to February) in the
west, with a dense, soft silky white fur; at first they are
small and shrivelled-looking, but they rapidly fatten up to
look like
over-filled barrels, from the extremely fat-rich milk they receive
from their mothers. Within a month or so, they shed the
pup fur and grow the dense waterproof adult fur, and soon leave
for the sea to learn to fish for themselves.
In recent years, the number of grey seals has been on the rise
in the west and in Canada there have been calls for a seal cull. |
Text
about the Gray Seal: http://en.wikipedia.org/wiki/Grey_seal
|
Bearded
seal, Erignathus barbatus
Close
view of a Bearded seal, Erignathus barbatus
Photo: Spindler,
Mike, USFWS
|
The bearded seal, Erignathus barbatus, also called the square
flipper seal, is a medium-sized pinniped that is found in
and
near to the Arctic Ocean. It gets its generic name from two
Greek words (eri and gnathos) that refer to its heavy jaw.
The other part of its Linnaean name means bearded and refers
to its most characteristic feature, the conspicuous and very
abundant whiskers. When dry, these whiskers curl very elegantly,
giving the bearded seal a raffish look.
Distinguishing features of this earless seal include square
fore flippers and thick bristles on its muzzle. Adults are
greyish-
brown in colour, darker on the back; rarely with a few faint
spots on the back or dark spots on the flanks.
Occasionally the face and neck are reddish-brown. Bearded
seal pups are born with a greyish-brown natal fur with scattered
patches of white on the back and head. The bearded seal is
unique in the subfamily Phocinae in having two pairs
of nipples,
a feature it shares with monk seals. |
Bearded
seal, Northern Bering Sea
Photo: Labunski, Liz
|
The bearded seal reaches about 2.1 m to 2.7
m in nose-to-tail length and from 200 kg to 430 kg in weight.
Both sexes are about the same size.
The bearded seal is a primary food source for the polar
bear and for the Inuit of the Arctic coast. The Inuktitut
name for
the seal is Ugyuk or Oogrook or Oogruk. The seal's skin is
used to cover a wooden frame boat (Umiak).
The body fat content of a bearded seal is 3040%. |
Bearded
seal - overview
Video: © BBC
Natural History Unit
Audio credits: © Master Tracks & © BBC Natural History
Unit
www.arkive.org
|
Primarily benthic, the bearded seal feeds on
a variety of small prey found along the ocean floor, including
clams, squid, and
fish. Its whiskers serve as feelers in the soft bottom sediments.
Adults tend not to dive very deep, favoring shallow coastal
areas no more than 300 m deep. Pups up to one year old, however,
will venture much deeper, diving as deep as 450 m.
The bearded seal gives birth in the spring. In the Canadian
Arctic, seal pupping occurs in May. Further south, in Alaska,
most pups are born in late April. Pups are born on small drifting
ice floes in shallow waters, usually weighing around 3040
kg.
They enter the water only hours after they are born, and quickly
become proficient divers. Mothers care for the pups for
1824 days, during which time the pups grow at an average
rate of 3.3 kg per day. During this time, pups consume an
average of eight liters of milk a day. By the time they are
weaned, the pups have grown to about one hundred kilograms. |
Text
about the Bearded Seal: http://en.wikipedia.org/wiki/Bearded_seal
|
Ribbon
Seal, Phoca fasciata
Ribbon
Seal, Phoca fasciata, in Northern Bering Sea
Photo:
Labunski, Liz
|
The ribbon seal, Histriophoca fasciata, is a
medium-sized pinniped from the true seal family Phocidae.
A seasonally
ice-bound species, it is found in the Arctic and Subarctic regions
of the North Pacific Ocean, notably in the Bering Sea
and Sea of Okhotsk. It is distinguished by its striking coloration,
with two wide white strips and two circles against dark
brown or black fur. It is the only species in the genus Histriophoca
Adult seals are recognizable by their black skin, which
carries four white markings: a strip around the neck, one around
the tail and a circular marking on each body side, which encloses
the front fins. The contrast is particularly strong with the
males, while with females the difference in color between bright
and dark portions is often less conspicuous. |
Ribbon
seal pup on the ice
http://en.wikipedia.org/wiki/File:Ribbon_seal_pup_on_the_ice.jpg
|
Newborn ribbon seal pups have white natal fur.
After moulting their natal fur, their color changes to blue-grey
on their
backs and silvery beneath; after some years some portions become
darker and others brighter, and only at the age of four
years does the typical design show.
The ribbon seal has a large inflatable air sac that is connected
to the trachea and extends on the right side over the ribs.
It is larger in males than in females, and it is thought that
it is used to produce underwater vocalizations, perhaps for
attracting a mate. The ribbon seal can grow about 1.6 m long,
weighing 95 kg in both sexes. |
Text
about the Ribbon Seal: http://en.wikipedia.org/wiki/Ribbon_seal
|
Harbor
seal, Phoca vitulina
Harbor
seal, Phoca vitulina , and pup on Buldir Island
Photo: Byrd, Vernon
|
The harborseal, (or harbour seal), Phoca vitulina,
also known as the common seal, is a true seal found along temperate
and Arctic marine coastlines of the Northern Hemisphere. They
are found in coastal waters of the northern Atlantic and
Pacific Oceans, as well as those of the Baltic and North Seas,
making them the most widely distributed of the pinnipeds
(walruses, eared seals, and true seals).
Their global population is 5-6 million, but subspecies in certain
habitats are threatened. Seal hunting or sealing, once a
common practice, is now illegal in many nations within the animal's
range. |
Harbor
seal rests on the northern California coast
Photo: Blake, Tupper Ansel
|
Common seals are brown, tan, or gray, with distinctive
V-shaped nostrils. An adult can attain a length of 1.85 meters
and a mass of 132 kilograms. Females outlive males (3035
years versus 2025 years). Common seals stick to familiar
resting spots or haulout sites, generally rocky areas (although
ice, sand and mud may also be used) where they are protected
from adverse weather conditions and predation, near a foraging
area. Males may fight over mates underwater and on land.
Females are believed to mate with the strongest males and generally
bear a single pup, which they care for alone.
Pups are able to swim and dive within hours of birth, and they
develop quickly on their mothers' fat-rich milk.
A fatty tissue layer called blubber is present under their skins
and helps to maintain body temperature. |
Common seal, Phoca vitulina - overview
BBC
Natural History Unit
http://www.arkive.org
|
These seals are rather curious, so sea kayakers sometimes
get the opportunity to see them close up. Seals also sometimes
swim along beaches, looking at beach walkers. The seals are
wary of humans on land, however, and will enter the water
at any opportunity. They do not attack humans, though, whether
on land or in the water. The seals can be very vocal,
especially in large groups, and are rather social animals.
With each individual possessing a unique pattern of fine, dark
spots (or light spots on a dark background in some variants),
they vary in color from brownish black to tan or grey; underparts
are generally lighter. The body and flippers are short,
with a proportionately large, rounded head. The nostrils appear
distinctively V-shaped; as with other true seals, there is
no ear flap, or pinna. A relatively large (for a seal) ear canal
may be visible behind the eye. Including the head and flippers,
they may reach an adult length of 1.85 meters and a weight of
55 to 170 kg. Females are generally smaller than males. |
Harbor
seal, Phoca vitulina, at Nantucket National Wildlife
Refuge, MA.
Photo:
Boyd, Amanda
|
With an estimated 5 million to 6 million individuals,
the population is not threatened as a whole; most subspecies
are secure
in numbers, with the Greenland, Hokkaido and Baltic Sea populations
being exceptions. Local populations have been
reduced or eliminated through outbreaks of disease (especially
the phocine distemper virus) and conflict with humans,
both unintentionally and intentionally, has also been linked
to common seal declines.
While it is legal to kill seals which are perceived to threaten
fisheries in the United Kingdom, Norway and Canada,
commercial hunting is illegal; the seals are also taken in subsistence
hunting and accidentally as bycatch in fishing nets.
Bycatch by fishing nets (mainly in bottomset nets) along the
Norwegian coast accounted for 48% of pup mortality.
In the United States, alternative protection applies and it
is illegal to kill any seals or any marine mammals, as they
fall
under the Marine Mammal Protection Act. On the East Coast of
the United States, their numbers seem to be increasing
quite steadily, as they are reclaiming parts of their range,
and have been seen as far south as Florida.
Female common seals have a life span of 3035 years, while
male life spans are usually 20-25. |
Text
about the Harbor Seal: http://en.wikipedia.org/wiki/Harbor_seal
|
Hawaiian
monk seal, Monachus schauinslandi
Hawaiian
Monk Seal
|
The Hawaiian monk seal, Monachus schauinslandi,
is an endangered species of earless seal in the Phocidae
family that is endemic to the Hawaiian Islands. The Hawaiian
monk seal is the only seal native to Hawaii.
They are solitary animals, like some monks. The Hawaiian monk
seal is one of two remaining monk seal species; the other
is the Mediterranean monk seal. A third species, the Caribbean
monk seal, is extinct.
These monk seals are a conservation reliant endangered species.
The small population of about 1,100 individuals is
threatened by human encroachment, very low levels of genetic
variation, entanglement in fishing nets, marine debris, disease,
and past commercial hunting for skins. There are many methods
of conservation biology when it comes to endangered
species; translocation, captive care, habitat clean up, and
educating the public about the Hawaiian monk seal are some
of the methods that can be employed. |
Hawaiian
Monk Seal and Pup
|
Known to native Hawaiians as 'Ilio-holo-i-ka-uaua,
or "dog that runs in rough water", its scientific
name is from Hugo
Hermann Schauinsland, a German scientist who discovered a skull
on Laysan Island in 1899. Its common name comes
from short hairs on its head, said to resemble a monk.
Its grey coat, white belly, and slender physique distinguish
them from their cousin, the Harbor seal,
Phoca vitulina.
The monk seals physique is ideal for hunting its prey:
fish, lobster, octopus and squid in deep-water coral beds.
When it is not hunting and eating, it generally basks on the
sandy beaches and volcanic rock of the NW Hawaiian Islands. |
An
endangered Hawaiian monk seal, Monachus schauinslandi,
lays on the beach near two red-footed boobies.
USFWS
|
Adult males are 140 to 180 kg in weight and 2.10 m in length
while adult females tend to be slightly larger, at 180 to 270
kg
and 2.40 m feet in length. When monk seal pups are born, they
average 14 to 18 kg and 1.0 m in length. As they nurse for
approximately six weeks, the grow considerably, eventually weighing
between 68 to 90 kg by the time they are weaned,
while the mother loses up to 140 kg. |
Text
about the Hawaiian Monk Seal: http://en.wikipedia.org/wiki/Hawaiian_monk_seal
|
Now, lets leave the seals, and look at one of their most dangerous
predators:
Polar
Bear, Ursus maritimus
Male
polar bear near Kaktovik, Alaska
Photo: Regehr, Eric
|
The polar bear, Ursus maritimus, is a bear native
largely within the Arctic Circle encompassing the Arctic Ocean,
its surrounding seas and surrounding land masses. It is the
world's largest land carnivore and also the largest bear,
together with the omnivorous Kodiak Bear, which is approximately
the same size.
Polar
bear - overview
Video:
BBC Natural History Unit, Audio: Master Tracks
www.arkive.org
|
An adult male weighs around 350680 kg, while an adult
female is about half that size. Although it is closely related
to the
brown
bear, it has evolved to occupy a narrower
ecological niche, with many body characteristics adapted for
cold
temperatures, for moving across snow, ice, and open water,
and for hunting the seals which make up most of its diet.
Although most polar bears are born on land, they spend most
of their time at sea. Their scientific name means "maritime
bear",
and derives from this fact. Polar bears can hunt their preferred
food of seals from the edge of sea ice, often living off fat
reserves when no sea ice is present. But the big question
is what to do when no more ice around.....
|
Male
Polar Bear on Pack Ice
Photo: Regehr, Eric
|
The polar bear is classified as a vulnerable species, with
eight of the nineteen polar bear subpopulations in decline.
For decades, large scale hunting raised international concern
for the future of the species but populations rebounded after
controls and quotas began to take effect. For thousands of
years, the polar bear has been a key figure in the material,
spiritual, and cultural life of Arctic indigenous peoples,
and polar bears remain important in their cultures.
Polar
bear hunting seal pup
Video:
BBC Natural History Unit, Audio: Master Tracks
www.arkive.org
|
The polar bear is found in the Arctic Circle and adjacent land
masses as far south as Newfoundland Island. Due to the
absence of human development in its remote habitat, it retains
more of its original range than any other extant carnivore.
While they are rare north of 88°, there is evidence that
they range all the way across the Arctic, and as far south as
James Bay in Canada. They can occasionally drift widely with
the sea ice, and there have been anecdotal sightings as
far south as Berlevåg on the Norwegian mainland and the
Kuril Islands in the Sea of Okhotsk. It is difficult to estimate
a global population of polar bears as much of the range has
been poorly studied; however, biologists use a working
estimate of about 20,00025,000 polar bears worldwide. |
A
polar bear looks out over a barrier island on the Arctic coast
of Alaska.
|
There are 19 generally recognized, discrete subpopulations.
The subpopulations display seasonal fidelity to particular areas.
The thirteen North American subpopulations range from the Beaufort
Sea south to Hudson Bay and east to Baffin Bay in
western Greenland and account for about 70% of the global population.
The Eurasian population is broken up into the eastern
Greenland, Barents Sea, Kara Sea, Laptev Sea, and Chukchi Sea
subpopulations, though there is considerable uncertainty
about the structure of these populations due to limited mark
and recapture data.
Polar
bear attacking walrus, drags off walrus pup
Video: BBC Natural History Unit, Audio:
Master Tracks & BBC Natural History Sound Library
www.arkive.org
|
The polar bear is often regarded as a marine mammal because
it spends many months of the year at sea. Its preferred
habitat is the annual sea ice covering the waters over the continental
shelf and the Arctic inter-island archipelagos.
These areas, known as the "Arctic ring of life", have
high biological productivity in comparison to the deep waters
of the
high Arctic. The polar bear tends to frequent areas where sea
ice meets water, such as polynyas and leads (temporary
stretches of open water in Arctic ice), to hunt the seals that
make up most of its diet. Polar bears are therefore found
primarily along the perimeter of the polar ice pack, rather
than in the Polar Basin close to the North Pole where the
density of seals is low.
Annual ice contains areas of water that appear and disappear
throughout the year as the weather changes. Seals migrate in
response to these changes, and polar bears must follow their
prey. In Hudson Bay, James Bay, and some other areas,
the ice melts completely each summer (an event often referred
to as "ice-floe breakup"), forcing polar bears to
go onto
land and wait through the months until the next freeze-up. In
the Chukchi and Beaufort seas, polar bears retreat each
summer to the ice further north that remains frozen year-round. |
Polar
Bear, Ursus maritimus, Female with Young along the
Beaufort Sea Coastline of Alaska.
Photo: Susanne
Miller
|
The polar bear is the largest terrestrial carnivore, being
more than twice as big as the Siberian
tiger. It shares this title with
the Kodiak Bear. Adult males weigh 350680 kg and measure
2.43 m in length. Adult females are roughly half the size
of males and normally weigh 150250 kg , measuring 1.82.4
metres in length. When pregnant, however, they can weigh
as much as 500 kg. The polar bear is among the most sexually
dimorphic of mammals, surpassed only by the pinnipeds.
The largest polar bear on record, reportedly weighing 1,002
kg , was a male shot at Kotzebue Sound in northwestern
Alaska in 1960. The shoulder height of the polar bear is 130160
cm. |
Polar
Bear Cubs, Ursus maritimus,
in the snow,
USFWS
|
The polar bear is the most carnivorous member
of the bear family, and most of its diet consists of ringed
and bearded seals. The Arctic
is home to millions of seals, which become prey when they surface
in holes in the ice in order to breathe, or when
they haul out on the ice to rest. Polar bears hunt primarily
at the interface between ice, water, and air; they only rarely
catch
seals on land or in open water.
The polar bear's most common hunting method is called still-hunting:
The bear uses its excellent sense of smell to locate a
seal breathing hole, and crouches nearby in silence for a seal
to appear. When the seal exhales, the bear smells its breath,
reaches into the hole with a forepaw, and drags it out onto
the ice. The polar bear kills the seal by biting its head to
crush
its skull. The polar bear also hunts by stalking seals resting
on the ice: Upon spotting a seal, it walks to within 90 m,
and then crouches. If the seal does not notice, the bear creeps
to within 9 to 12 m of the seal and then suddenly rushes
forth to attack. A third hunting method is to raid the birth
lairs that female seals create in the snow. |
Text
about the Polar Bear: http://en.wikipedia.org/wiki/Polar_bear
|
Its not a seal, nor a bear, but then - what is it? A cow?:
Manatee,
Trichechus manatus
Manatee
underwater
Photo: Hagerty, Ryan
|
Manatees, family Trichechidae, genus Trichechus)
are large, fully aquatic, mostly herbivorous marine mammals
sometimes
known as sea cows. There are three accepted living species of
Trichechidae, representing three of the four living species
in the order Sirenia: the Amazonian manatee, Trichechus
inunguis, the West Indian manatee, Trichechus
manatus,
and the West African manatee, Trichechus senegalensis.
They measure up to 4.0 m long, weigh as much as 590 kg),
and have paddle-like flippers.
The West Indian Manatee, Trichechus manatus, is the largest
surviving member of the aquatic mammal order Sirenia
(which
also includes the Dugong and the extinct Steller's
Sea Cow). |
Manatee,
Trichechus manatus
Photo: Powell, James A.
|
Like other manatees, the West Indian Manatee has adapted fully
to an aquatic life style, having no hind limbs. Pelage cover
is sparsely distributed across the body, which may play a role
in reducing the build-up of algae on their thick skin.
The average West Indian Manatee is approximately 2.73.5
m long and weighs 200600 kg, with females generally larger
than males. The largest individuals can weigh up to 1,500 kg
and measure up to 4.6 m. The Manatee's color is gray or
brown. Their flippers also have either 3 or 4 nails so they
can hold their food as they are eating. |
Manatee
Rooting in Sand
Photo: Reid, Jim P.
|
As its name implies, the West Indian manatee lives in the
West Indies, or Caribbean, generally in shallow coastal areas.
However, it is known to withstand large changes in water salinity,
and so has also been found in shallow rivers and estuaries.
They can live in fresh water, saline water, and even brackish
water. It is limited to the tropics and subtropics due to an
extremely low metabolic rate and lack of a thick layer of insulating
body fat. In the winter, West Indian Manatees can be
found in Florida. During summer, these large mammals have even
been found as far north as New York City, New York
and as far west as Texas. |
Manatee,
Trichechus manatus latirostris, swims near Crystal
River National Wildlife Refuge
Notice all the
small fishes below the Manatee
Photo: Ramos, Keith
|
The West Indian Manatee is surprisingly agile
in water, and individuals have been seen doing rolls, somersaults,
and even
swimming upside-down. Manatees are not territorial and do not
have complex predator avoidance behavior, as they live
in areas without natural predators. The common predators of
marine mammals, such as orcas and large sharks, are rarely
(if ever) found in habitats inhabited by this species.
The West Indian Manatee is an opportunistic feeder, with large
adults consume 10% to 15% of the body weight in food daily.
Manatees feed on about 60 plant species which includes sea grasses
as their major food source. They also consume some
fish and small invertebrates. Because manatees feed on abrasive
plants, their molars are often worn down and are continually
replaced throughout life.
Two
manatee rooting for food in bottom sand of Crystal River
National Wildlife Refuge
West Indian manatee , Trichechus manatus
Photo:
Reid, Jim P.
|
The West Indian Manatee has a high casualty rate due to thermal
shock from cold temperatures. During cold weather many
die due to their digestive tract shutting down at water temperatures
below 20 °C. Many manatee deaths are caused by
large commercial vessels but are attributed to "recreational
watercraft" due to the elimination of that classification. |
West
Indian manatee, Trichechus manatus
Manatee cow and calf swimming side-by-side in Crystal River.
Photo:
Perrine, Doug
|
For more information about manatees visit http://www.fws.gov/northflorida/manatee/manatees.htm.
Text
about the Manatee:http://en.wikipedia.org/wiki/West_Indian_Manatee
|
We like those old drawing, and let's follow them a bit longer.
We have looked at the bears, now the smaller animals:
Bears,
raccoons, opossoms
Creator: Hines, Bob
The raccoon comes first:
Raccoon,
Procyon lotor
Raccoon,
Procyon lotor
Photo: Burton, Robert
|
The raccoon, Procyon lotor, (sometimes spelled racoon),
also known as the common raccoon, North American raccoon,
northern raccoon and colloquially as coon, is a medium-sized
mammal native to North America.
It is the largest of the procyonid family, having a body
length of 40 to 70 cm and a body weight of 3.5 to 9 kg.
The raccoon is usually nocturnal and is omnivorous, with a diet
consisting of about 40% invertebrates, 33% plant foods,
and 27% vertebrates. It has a grayish coat, of which almost
90% is dense underfur, which insulates against cold weather.
Two of its most distinctive features are its extremely dexterous
front paws and its facial mask, which are themes in the
mythology of several Native American tribes. Raccoons are noted
for their intelligence, with studies showing that they
are able to remember the solution to tasks up to three years
later. |
Raccoon
Photo: Hollingsworth,
John and Karen
|
The original habitats of the raccoon are deciduous and mixed
forests of North America, but due to their adaptability they
have extended their range to mountainous areas, coastal marshes,
and urban areas, where many homeowners consider
them to be pests. As a result of escapes and deliberate introductions
in the mid-20th century, raccoons are now also
distributed across the European mainland, the Caucasus region
and Japan.
Northern
raccoon hunting crayfish in stream
BBC
Natural History Unit
www.arkive.org
|
Though previously thought to be solitary, there is now evidence
that raccoons engage in gender-specific social behavior.
Related females often share a common area, while unrelated
males live together in groups of up to four animals to maintain
their positions against foreign males during the mating season,
and other potential invaders.
Home range sizes vary anywhere from 3 hectares for females
in cities to 50 km2 for males in prairies. After a gestation
period of about 65 days, two to five young (known as a "kit",
plural "kits") are born in spring. The kits are
subsequently
raised by their mother until dispersion in late fall. Although
captive raccoons have been known to live over 20 years, their
average life expectancy in the wild is only 1.8 to 3.1 years.
In many areas hunting and traffic accidents are the two most
common causes of death.
|
Raccoon
in a tree on the Lower Klamath National Wildlife Refuge
Photo:
Menke, Dave
|
Though usually nocturnal, the raccoon is sometimes active
in daylight to take advantage of available food sources.
Since its diet consists of a variety of different foods, Zeveloff
argues the raccoon "may well be one of the world's most
omnivorous animals".While its diet in spring and early
summer consists mostly of insects, worms, and other animals
already
available early in the year, it prefers fruits and nuts, such
as acorns and walnuts, which emerge in late summer and autumn,
and represent a rich calorie source for building up fat needed
for winter.
They eat active or large prey, such as birds and mammals, only
occasionally, since they prefer prey that is easier to catch,
specifically fish and amphibians. Bird nests (eggs and after
hatchlings) are frequently preyed on, and small birds are often
helpless to prevent the attacking raccoon. When food is plentiful,
raccoons can develop strong individual preferences for
specific foods. In the northern parts of their range, raccoons
go into a winter rest, reducing their activity drastically as
long
as a permanent snow cover makes searching for food impossible. |
Raccoon,
Procyon lotor, in Crab Apple Tree, PA.
Photo:
Buchanan, Bill
|
Raccoons sample food and other objects with their front paws
to examine them and to remove unwanted parts.
The tactile sensitivity of their paws is increased if this action
is performed underwater, since the water softens the horny
layer covering the paws. However, the behavior observed in captive
raccoons in which they carry their food to a watering
hole to "wash" or douse it before eating has not been
observed in the wild.
Captive raccoons douse their food more frequently when a watering
hole with a layout similar to a stream is not farther
away than 3 m. The widely accepted theory is that dousing is
a vacuum activity imitating foraging at shores for aquatic foods.
This is supported by the observation that such foods are doused
more frequently. Cleaning dirty food does not seem to be
a reason for "washing". Experts have cast doubt on
the veracity of observations of wild raccoons dousing food.
But why shouln't animals also have good behaviours? |
Text
about the Raccoon: http://en.wikipedia.org/wiki/Raccoon
|
The Opossum
is next, but it has gone to South
America, so lets go on to other small animals:
Yellow-bellied
marmot, Marmota flaviventris
Marmot
(specimen?)
Creator Leupold, James C.
|
The marmots are a genus, Marmota, of squirrels.
There are 14 species in this genus. We will discuss them
later.
Marmots are generally large ground squirrels. Those most often
referred to as marmots tend to live in mountainous areas
such as the Alps, northern Apennines, Eurasian steppes, Carpathians,
Tatras, and Pyrenees in Europe and northwestern Asia;
the Rocky Mountains, Black Hills, Cascades, and Sierra Nevada
in North America; and the Deosai Plateau in Pakistan and
Ladakh in India. The groundhog, however, is also sometimes called
a marmot, while the similarly sized but more social
prairie dog is not classified in the genus Marmota
but in the related genus Cynomys.
Marmots typically live in burrows (often within rockpiles, particularly
in the case of the Yellow-bellied marmot),
and hibernate there through the winter. Most marmots are highly
social, and use loud whistles to communicate with one
another, especially when alarmed.
Marmots mainly eat greens and many types of grasses, berries,
lichens, mosses, roots and flowers. |
Marmot
(specimen?)
Creator Hickey, Bill
|
The yellow-bellied marmot, Marmota flaviventris, also known
as the rock chuck, is a ground squirrel in the marmot
genus.
Yellow-bellied marmots are generally small to medium sized.
The post-hibernation weight of adults averages 3.9 kg for males
and 2.8 kg for females. The total body length is 47 -70 cm with
a 13-22 cm long tail. Males tend to be longer in length than
females. Marmots have thick bodies and short broad heads. The
dental formula is[2] .
Their ears are small and well furred. The feet have five digits
with stoat and slightly curved claws.
The thumb is rudimentary but bears a nail. The palms of the
paws have five pads with three at the base of the digits and
the
posterior pad being oval in shape.The marmot has soft, dense
somewhat woolly underfur, especially on the back and sides.
Its outer guard hairs are longer and coarser and cover the entire
body. The overall color is yellowish brown to tawny and
has light tips and darker subterminal bands of many dorsal guard
hairs giving it a frosted appearance.Marmots also have
distinct yellow speckles on the sides of their necks and white
between their eyes. Coloration, however, can vary even within
subspecies. Partial or fully melanistic individuals are common
in populations from the southern Rockies from Wyoming to
New Mexico. |
Text
about the Yellow-bellied Marmot: http://en.wikipedia.org/wiki/Yellow-bellied_Marmot
|
Mexican
Ground Squirrel,
Spermophilus mexicanus
Mexican
Ground Squirrel on the Lower Rio Grande Valley National Wildlife
Refuge
Ditto, Larry
|
The Mexican Ground Squirrel, , is found from extreme southeastern
New Mexico through western
and central Texas, south to Coahuila, Nuevo Leon, and Tamaulipas
(Mexico). There is disjunct population in central Mexico.
A rather small ground squirrel with usually nine rows of squarish
white spots on back; tail about two-fifths of total length,
moderately bushy; ears short and rounded; upperparts wood brown
or buffy brown with rows of conspicuous white spots;
sides and underparts whitish or pinkish buff. External measurements
average: total length, 30 cm; tail, 12 cm; hind foot, 4cm..
Weight, (males) 227-330 g; 137-198 g.
Mexican ground squirrels inhabit brushy or grassy areas. In
southern Texas, they are frequently associated with mesquite
and cactus flats. In Kerr County, they are most common in pastures
and along the highways; in Trans-Pecos Texas,
they are frequently found in areas dominated by creosote-bush
Their food in early spring is chiefly green vegetation. They
are known to feed on mesquite leaves and beans, agarita leaves
and berries, Shasta lily, Johnson grass, pin clover, and cultivated
grains. Insects also contribute importantly to their diet.
In early summer about half of their diet is insects. They are
fond of meat and frequently can be seen feeding upon
small animals killed on the highways. |
Text
about the Mexican Ground Squirrel: Mammals of Texas, http://www.nsrl.ttu.edu/tmot1/spermexi.htm
|
That brings
us to the end of page 2 of this North American Wildlife tour.
As per February 21st, 2012, the next 3 or more pages are not
yet ready,
but you may try page three
right now.
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