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the rapid loss of sea-ice area, the shrinking sea-ice "season", longer & longer periods land-bound & unable to hunt, impossible vast areas of open sea between seal haul-outs... the bad news keeps coming.
A new study captures incredible data over a week or more of adult bears, each radio-collared, including video of them hunting, miles traveled or swum, activity levels, metabolic needs, wt gain or wt loss, & more.
the worst bit? - We now know they need more than HALF AGAIN the amount of calories that we previously thought, daily.
We also have definitive proof of just how critical blubber-wrapped ring seals are to their survival, as individuals or as a species:
Bears who successfully found & caught ringed seals GAINED wt, an average of 40# over the 8 to 11 days that each one collected data.
Bears who found no seals, or who found them but failed to catch them, lost a similar amount of body-mass, over the same period.
In the late 1990s, I saw footage for the 1st time in my life of a healthy young male sea-bear, who was dying.
He was swimming in open ocean, over 90-miles from the nearest land, & he was shivering as he swam. Normally, polar bears have trouble shedding heat - their transparent thick coats capture any sunlight, & channel it to their skin. Their own fat insulates them so well, they lie down on the ice or "snow-plow" along on their chests thru the snow, to cool off.
When he heaved himself onto a small ice-floe about 15-ft square, it was immediately apparent just how thin he was - his flanks were hollow, his hip-bones protruded like an old milch-cow's, he was lank & slab-sided; his paws & head looked too big for his body.
He was just days from being too cold to swim, & drowning, or too exhausted to hunt - & death.
Females are not getting pregnant.
They must have a certain minimum body-fat to enter estrus, & then carry a pregnancy, give birth, & nurse the cub/s. // Normally, an adult F has 2 or even 3 cubs, spends 2 years to 3 years rearing them, & then enters estrus again.
Now? - they're too skinny to come into heat; or they get pregnant, then resorb the cub/s B4 they're full-term; or they give birth, but the cubs can't thrive & grow 'cuz mom's not eating enuf to provide abundant, fat-rich milk, & the babies die.
From 2 or 3 cubs every 2 to 3 years, fertility has fallen to ONE cub every 2 to 3 years, or even ONE cub every 5 to 6; fewer than half as many births, but even fewer are living to adulthood, to mate in their turn.
Marathon swims are becoming more common - & more lethal. Cubs, especially, chill & drown.
Polar bears’ life-threatening journeys
I think that sea-bears may be functionally extinct, if not factually so, before i die.
What a bitterly sad prospect.
The 1st photo is of one of the females they collared - the other 2 are file photos; the last is an adult male, in good condition.
- terry
.
the rapid loss of sea-ice area, the shrinking sea-ice "season", longer & longer periods land-bound & unable to hunt, impossible vast areas of open sea between seal haul-outs... the bad news keeps coming.
A new study captures incredible data over a week or more of adult bears, each radio-collared, including video of them hunting, miles traveled or swum, activity levels, metabolic needs, wt gain or wt loss, & more.
the worst bit? - We now know they need more than HALF AGAIN the amount of calories that we previously thought, daily.
We also have definitive proof of just how critical blubber-wrapped ring seals are to their survival, as individuals or as a species:
Bears who successfully found & caught ringed seals GAINED wt, an average of 40# over the 8 to 11 days that each one collected data.
Bears who found no seals, or who found them but failed to catch them, lost a similar amount of body-mass, over the same period.
In the late 1990s, I saw footage for the 1st time in my life of a healthy young male sea-bear, who was dying.
He was swimming in open ocean, over 90-miles from the nearest land, & he was shivering as he swam. Normally, polar bears have trouble shedding heat - their transparent thick coats capture any sunlight, & channel it to their skin. Their own fat insulates them so well, they lie down on the ice or "snow-plow" along on their chests thru the snow, to cool off.
When he heaved himself onto a small ice-floe about 15-ft square, it was immediately apparent just how thin he was - his flanks were hollow, his hip-bones protruded like an old milch-cow's, he was lank & slab-sided; his paws & head looked too big for his body.
He was just days from being too cold to swim, & drowning, or too exhausted to hunt - & death.
Females are not getting pregnant.
They must have a certain minimum body-fat to enter estrus, & then carry a pregnancy, give birth, & nurse the cub/s. // Normally, an adult F has 2 or even 3 cubs, spends 2 years to 3 years rearing them, & then enters estrus again.
Now? - they're too skinny to come into heat; or they get pregnant, then resorb the cub/s B4 they're full-term; or they give birth, but the cubs can't thrive & grow 'cuz mom's not eating enuf to provide abundant, fat-rich milk, & the babies die.
From 2 or 3 cubs every 2 to 3 years, fertility has fallen to ONE cub every 2 to 3 years, or even ONE cub every 5 to 6; fewer than half as many births, but even fewer are living to adulthood, to mate in their turn.
Marathon swims are becoming more common - & more lethal. Cubs, especially, chill & drown.
Polar bears’ life-threatening journeys
I think that sea-bears may be functionally extinct, if not factually so, before i die.
What a bitterly sad prospect.The 1st photo is of one of the females they collared - the other 2 are file photos; the last is an adult male, in good condition.
- terry
.
