Cannibalism: Is climate
change causing polar
bears to eat each other?
allvoices.com
Polar bear eating cub in a sea
of melted ice with very little food
available. Photo by researcher Jenny E. Ross
Polar bears were listed as "threatened"
under the Endangered Species Act
(ESA) in 2008, following a petition by
environmental groups. The decision
was upheld in the D.C. Circuit Court
early in 2013, after a challenge by the
State of Alaska, sport hunters and other
special interest groups.
under the Endangered Species Act
(ESA) in 2008, following a petition by
environmental groups. The decision
was upheld in the D.C. Circuit Court
early in 2013, after a challenge by the
State of Alaska, sport hunters and other
special interest groups.
The polar bear listing represented the
first animal placed under ESA protection
solely as a result of climate change, which
is the cause of melting Arctic sea ice where
polar bears live and hunt for food.
first animal placed under ESA protection
solely as a result of climate change, which
is the cause of melting Arctic sea ice where
polar bears live and hunt for food.
Cannibalism and infanticide is one of the
dark sides of nature and it is not uncommon
in many species, but scientists report an
increase in polar bears feasting on cubs
and females in recent years.
dark sides of nature and it is not uncommon
in many species, but scientists report an
increase in polar bears feasting on cubs
and females in recent years.
Stories of such gruesome activities go
back to the late 1800s, but challengers
say there are more sightings now due to
increased accessibility by researchers
with cameras. Recent disturbing
eyewitness accounts reported by Discovery
Channel told of males taking cubs and
attacking females in their dens.
back to the late 1800s, but challengers
say there are more sightings now due to
increased accessibility by researchers
with cameras. Recent disturbing
eyewitness accounts reported by Discovery
Channel told of males taking cubs and
attacking females in their dens.
One scientist says polar bears, the largest
of the bear species, do it "just because
they can."
of the bear species, do it "just because
they can."
Dr. Susan J. Crockford is a zoologist, who
claims polar bears kill each other for a
number of reasons. Excerpt from her website:
claims polar bears kill each other for a
number of reasons. Excerpt from her website:
"Male bears kill newborn cubs in the spring
to bring females into estrus – so that they
are able and willing to mate again with the
new male (this only works until perhaps early
June at the latest); 2) females may eat their
young (probably at any time of year) when
they can't get other food; 3) males will kill
adult females, smaller bears and cubs at
any time of year and eat them – whether they
are thin or fat, truly hungry or not – just
because they can."
to bring females into estrus – so that they
are able and willing to mate again with the
new male (this only works until perhaps early
June at the latest); 2) females may eat their
young (probably at any time of year) when
they can't get other food; 3) males will kill
adult females, smaller bears and cubs at
any time of year and eat them – whether they
are thin or fat, truly hungry or not – just
because they can."
Evidently, polar bears are a murderous
bunch.
bunch.
Nonetheless, other researchers believe
starvation is driving polar bears to turn on
their own as food becomes less reachable
due to melting ice.
starvation is driving polar bears to turn on
their own as food becomes less reachable
due to melting ice.
Dr. Ian Stirling of Environment Canada has
been studying polar bears for more than 40
years and he believes early ice melts are the
cause of more cannibalism reports. Ice floes
melt in summer, with many disappearing
totally, making hunting for the bear's favorite
food of seals more difficult, which forces them
to roam further and settle for less; like sea
birds and their eggs.
been studying polar bears for more than 40
years and he believes early ice melts are the
cause of more cannibalism reports. Ice floes
melt in summer, with many disappearing
totally, making hunting for the bear's favorite
food of seals more difficult, which forces them
to roam further and settle for less; like sea
birds and their eggs.
According to an article in The Guardian,
Stirling recently examined the body a polar
bear that had been tracked by scientists
for several years during healthy conditions,
but was found dead of starvation in southern
Svalbard series of Arctic Islands near Norway.
Stirling recently examined the body a polar
bear that had been tracked by scientists
for several years during healthy conditions,
but was found dead of starvation in southern
Svalbard series of Arctic Islands near Norway.
"From his lying position in death the bear
appears to simply have starved and died
where he dropped," Stirling said. "He had
no external suggestion of any remaining fat,
having been reduced to little more than skin
and bone."
appears to simply have starved and died
where he dropped," Stirling said. "He had
no external suggestion of any remaining fat,
having been reduced to little more than skin
and bone."
Furthermore, ships have occasionally spotted
polar bear bodies floating at sea after
apparently drowning; most likely while
swimming in search of solid ice after being
trapped on melting floes. Since drowned
bears eventually sink to the ocean floor,
it's hard for scientists to know the extent
of this problem. Polar bears are massively
skilled swimmers, but in poor fitness they
are more vulnerable.
polar bear bodies floating at sea after
apparently drowning; most likely while
swimming in search of solid ice after being
trapped on melting floes. Since drowned
bears eventually sink to the ocean floor,
it's hard for scientists to know the extent
of this problem. Polar bears are massively
skilled swimmers, but in poor fitness they
are more vulnerable.
The condition of Arctic sea ice has been
monitored by satellites for more than 50 years.
It shrinks in the spring and summer and it
expands during the late fall and winter. It has
been measured up to 9 feet deep in places
and has reportedly decreased by 40 percent
since the 1970s. In 2012, sea ice levels were
the lowest in recorded history and scientists
blame global warming.
monitored by satellites for more than 50 years.
It shrinks in the spring and summer and it
expands during the late fall and winter. It has
been measured up to 9 feet deep in places
and has reportedly decreased by 40 percent
since the 1970s. In 2012, sea ice levels were
the lowest in recorded history and scientists
blame global warming.
Regardless of the "common" claim by many
to explain cannibalism in polar bears, others
feel that "common sense" should figure into
the equation when polar bears are facing a
mortal scarcity of food due to a melting habitat.
to explain cannibalism in polar bears, others
feel that "common sense" should figure into
the equation when polar bears are facing a
mortal scarcity of food due to a melting habitat.
Many experts feel polar bears could be
virtually extinct in the next 50-100 years if
climate change stays on its current path.
virtually extinct in the next 50-100 years if
climate change stays on its current path.
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