Eventually humans stop growing, I'm pretty tall, but I'll never get any taller, only
shorter.
Sharks?
They just keep.
Getting.
More.
AWESOME.
Earlier this month, photographers filmed the largest great white shark ever spotted in
the wild.
Most great whites normally grow 12 to 14 feet long (3.6-4M), but this one, named Deep Blue,
was 20 feet long (6M)!
The director of a non-profit that supports Pacific marine species, like these sharks,
says seeing one so large means hope for these animals.
Sharks live a long time, 73 years, and a 2014 paper in Marine & Freshwater Research found
sharks can take 23 to 33 years to reach full maturity.
Human size is set from birth.
We grow until we reach a genetically pre-determined size and then we stop.
As we go through puberty, our body begins to make sex hormones like estrogen -- both
men and women produce estrogen, women just have more.
Estrogen ultimately makes the growth plates of our bones fuse, stopping growth forever.
But that doesn't happen in sharks -- they'll keep growing after maturity until they die,
just more slowly.
Based on her size, Deep Blue is probably 50 years old; bigger sharks means humans ain't
killing them.
Plus, they can breed for longer and age naturally.
Sharks aren't unique in this ability though, corals, lizards, snakes, and amphibians all
grow continuously until they die -- all these animals are "indeterminate growers," and they're
frickin' awesome.
Kangaroos and wallabies, slowly get bigger as they age, until they're killed or die of
disease.
The Rocky Mountain bristlecone pine can live for thousands of years, growing all the time.
A 2001 study of one tree found it hadn't had a significant mutation in its pollen or seeds
over 4700 years.
At some point, the trees stop getting taller, but continue to thicken at the trunk as long
as they have the resources.
Continuous growing is inextricably dovetailed with aging.
Tortoises will keep getting larger, but super slowly, and their internal organs suffer little
mutation over time.
The bristlecone pine does the same and simply does not mutate over time.
Why?
We’re not really sure.
So even though sharks may live 70-plus years, they WILL age and die naturally.
Some animals, like tortoises for example, have what is called "Negligible Senescence,"
i.e. they don't appear to age at all; evolution didn't program a natural limit to their lives.
With humans, tiny tails on our genes called telomeres seem to be key to dictating a biological
end to our lives -- we've talked about this in other DNews videos, If you were a subscriber,
you'd know that.
Some sharks, turtles, whales, and fish have all identified as Negligibly Senescent and
many grow forever.
A Rougheye Rockfish was caught, and by looking at it's growth periods -- like rings on a
tree -- they found it was 205 years old.
Just hanging out.
Lobsters will continue growing until preyed upon or killed from disease, reproductive
competition or habitat destruction.
One 20 pound (9kg) specimen was found which is believed to be 140 years old and another
was caught in 1926 weighing 51.5 lbs… how old was it?
No idea.
They didn't save it.
They ate it.
Presumably with delicious, delicious butter.
By studying animals with indeterminate growth and negligible senescence we've learned a
lot about the aging process, but also about how resources can affect periods of growth.
Imagine if the longer we lived the more we grew!
My 90-year-old grandma be huge!
I dunno, I kind of like being able to wear the same shirts for 15 years or more…
Would you want to keep getting taller?
If we hadn't killed them, many of these animals would still be around, just like the rhinoceros.
But unlike the giant kangaroo or super-lobster, there's a crazy plan to save the rhino using
3D printing.
CTA to Seeker Rhino 3D Printed Horn