Posted in Africa, Cancer, Elephants, Nonfiction, Photography, Writing

Why Don’t Elephants Get Cancer?

 

photograph by Cheryl Merrill
photograph by Cheryl Merrill

 

This collared elephant, photographed in Botswana’s Chobe National Park, has a large breast mass – most likely mastitis, an inflammation or abscess of breast tissue often caused by blocked milk ducts. Although harmful bacteria may be present in her milk, nursing might relieve her mastitis symptoms. I don’t know the outcome for this mother, but it’s highly unlikely her breast mass was cancer related. Why? For elephants, the overall lifetime chance of dying from cancer is less than 5%. The mortality rate for humans is 20%.

Why should a mammal with 100 times more cells than we do have such a low cancer rate? Oddly enough, there is little relationship between cancer rates and body size of mammals – even though the cells of elephants will divide many more times throughout their lifetimes than ours will, simply because they have so many more of them. Elephants ought to have a greater quantity of random mutations predisposing them to cancer than we do.  But they don’t.

Studies using the autopsy reports of 36 mammals at the San Diego Zoo (ranging in size from mice to elephants) and the database of 644 captive Asian and African elephants confirmed that the relationship of cancer to body size did not matter. But those studies also found something highly unusual in the blood cells of elephants. African elephants have twenty TP53 genes (and therefore 40 alleles of that gene); Asian elephants have fifteen. TP53 is sometimes called the “guardian of the genome” for its ability to create a protein that suppresses tumors.

Humans have just one gene and two alleles of TP53. (An allele is basically a copy of a specific gene at the same position on a chromosome.   Chromosomes are located in the nucleus of cell and contain DNA, the genetic instructions that make mice mice and elephants elephants.) In humans, one allele is inherited from each parent – both crucial to prevent cancer. Having only one allele causes Li-Fraumeni syndrome, which is characterized by a more than 90% lifetime risk of cancer.

TP53 codes for the protein p53, a crucial tumor suppressor that stops cells with damaged DNA from dividing. TP53 goes into action when cells suffer DNA damage, churning out copies of its associated p53 protein and either repairing the damage or killing off the cell. But instead of repairing DNA damage, compromised elephant cells have evolved to always commit suicide rather than pass on potentially harmful mutations acquired in trying to repair itself. Once the damaged cell is dead and gone, it can’t turn into cancer.

Most of the elephant TP53 genes are retrogenes, which evolved into their genome at a later time than the original gene. Two factors explain why elephants developed more TP53 genes: a long gestation period (22 months) and a reproductive lifespan that lasts well into their 50s (elephants live 60+ years in the wild). Unlike mice, elephants don’t reproduce often – thus they pass along the extra copies of TP53 even in old age, and their progeny benefit.

In contrast, humans reproduce only into to middle age and most of our cancers are diseases of aging. We are the legacy of short-lived ancestors (compared to modern life expectations), who mostly didn’t get cancer throughout their years of reproduction and raising children. As modern humans age, our chances of contracting cancer become greater since we have less suppressing genes than elephants do. And any cancer-fighting mutations within our genes don’t get passed along in our older years.

Do elephant genes hold the secret of a cure for cancer? Researchers are investigating. Meanwhile, elephants are being slaughtered for their ivory, for short-term gains. What if elephants were our saviors, our partners in longer, healthier lives? What if elephants were worth much more alive than dead? #worthmorealive Spread the word.

 

Posted in Africa, Birds, Nature, Nonfiction, Photography, Travel, Writing

Camp Staff

photograph by Cheryl Merrill
photograph by Cheryl Merrill

 

I turn my head toward the sun’s white-hot eye. Behind my closed eyelids burn a thousand childish sketches of red suns. I hear one of the regular camp staff scratching around my feet for crumbs: a Red-billed Francolin, who believes his territory includes the kitchen shelter and its surroundings. The color of his legs, feet and bill match, but they look more orange than red to me. He’s plump as a pillow, with a bright yellow circle around each eye – but woe to any other francolin who trespasses. The resulting chases are explosive, noisy, and continue until he’s satisfied the intruder is back in the bush where he belongs. Male francolins have spurs on their legs, and they don’t hesitate to use them in fights. When he’s this close I can see the tiny black claws at the end of his toes, and hear his soft chuckles when he finds another crumb.

Posted in Africa, Elephants, Nature, Nonfiction, Photography, Travel, Writing

Drinking It In

Photograph by Cheryl Merrill
Photograph by Cheryl Merrill

 

Not far from here jungles of papyrus lean their feathery seed heads over the clear blue channels of the Okavango River, tall stands of reeds that line the permanent footprint of the Delta. The river is inching southward, breaking the boundary between water and desert. Soon it will flush this lagoon, scouring out the sweet muck at its bottom to spread among grassy floodplains.

With the river will come crocodiles and hippos and other denizens of its deep, running water. When the river reaches this part of the Delta, a new population of birds will arrive with it: Wattled cranes, Egyptian geese, Reed cormorants, Darters, Avocets, Black crakes, Red-knobbed coots, Sacred ibis, Hamerkops, Fish eagles, and Saddle-bill storks.

Standing shoulder to shoulder on a mat of trampled reeds, two elephants blow a concert of bubbles, bassoons under water. They shower their spines, poke their trunks into the back of their throats and release gallons of water at a time. Corkscrew spirals spill from their mouths, patter like rain on the surface of the lagoon. Sky-blue ripples spread from one edge to another, bounce back images of a thousand suns.

Believe me: you could spend the rest of your life watching this.

 

Posted in Africa, Hyenas, Lions, Nonfiction, Photography, Travel

Sunsets Like This

photograph by Cheryl Merrill
photograph by Cheryl Merrill

 

The sky turns orange and the clouds turn yellow. Sunsets like this one have hung in galleries for centuries. A slight breeze rises – the lungs of the earth inhaling warmth, exhaling coolness. The breeze brings a faintly watery smell, even though the sun still warms the tops of trees. Beneath the trees, in cool green-black shadows, night begins, spreading a transitory stillness that will soon fill with the Invisibles – hyenas, leopards, lions – beginning their nightly rounds.

 

Posted in Africa, Elephants, Nonfiction, Photography, Travel, Writing

Black Mamba in Toilet!

The most popular post in 2015:

Dated 5/26/12, Reconfirmed 5/30/12!

First, for those who are unfamiliar with black mambas, here’s a little background information:

Black mambas (Dendroaspis polytepsis) are the longest venomous snakes in Africa, measuring up to 14 ½ feet.  Mambas are not black – they’re more olive or greenish gray, with a narrow, elongated head the shape of a coffin.  It’s the inside of their mouths that are black – hence the name.  Mambas are also extremely aggressive and may actively attack without provocation.  I use the adverb “actively” with reason – a mamba can strike in all directions, even though a third of its body is raised above the ground, and it can chase you in that upright position at speeds up to 20 mph.  If you are bitten, your death will occur within 20-60 minutes.  An anti-venom for mamba bites exists, but it must be administered immediately, requiring 10-20 vials of solution.  But if you are struck in the face or neck (quite likely, since the head of the mamba chasing you is 4 feet off the ground), you will die in ten minutes. That black mouth will be the last thing you see.

On that cheery note, on with the story:

In the Moremi Game Reserve, east of the Okavango Delta, is an elevated platform overlooking a large hippo pool in a bend of the Khwai River.  Six of us, our guide OT (“just like Overtime!”) arrive in our Land Rover.

“What’s that?” I point.

It’s a large piece of stiff white paper taped with duct tape to a tree.  We climb out, read it, and immediately start swiveling our heads, trying to look in all directions at once.

“Anyone want to go look?” OT laughs.

The toilet, roughly the size of those cartoon outhouses with the crescent moons carved in their doors, is a cinder block building with a tin roof.  It’s about fifty feet from our Land Rover.  The painted green door on the toilet is ajar.

Certainly I’m not tempted to look inside.  After all, the second message (“Confirmed 30/5”) was written just three days before our arrival by someone a lot more curious than I am about deadly snakes.  The mamba is most likely still in there.  Who wants to reconfirm a reconfirmation?   Mambas are territorial; they will always return to their lairs, although that’s usually in an abandoned termite mounds or a hollow tree, rarely, I’d bet extremely rarely, in a toilet.  A mamba is diurnal, active both night and day.  It could be sleeping in there.  Or not.

In my opinion, I’m already standing way too close to that toilet.  Trying to look both at the toilet and at everything else, I walk slowly backwards.  Mambas don’t like sudden movements.

Besides, I firmly believe, even though I haven’t seen it, that this toilet is not a Western ceramic throne, but a mere hole in the cement.  I’ve had enough experience with toilets-in-the-middle-of-nowhere to also believe that the area around the hole is likely none-too-clean.  That bush over there looks a better.  A few minutes later, after careful reconnoitering and quickly taking care of business, I can confirm that no mambas are lurking around it.

As I climb the steps to the viewing platform I look for mambas wrapped around posts.  On the creaky platform I look for mamba’s hidden in corners, or nestled into the thatch of the roof.  I look for mambas slithering across the branches of the trees that lean dangerously close to the rails.  A rustling noise among the branches spikes my heart rate to a gazillion, but it calms when I see it’s only a Burchell’s glossy starling, squawking for handouts.

Burchell’s starling

The view from the platform is wonderful.  A massive cloud hangs over the hippo pool and puffs of other clouds reflect in the tranquil water.  A dozen hippos rise and sink, burbling like submerged tubas.  Tracks in the grass are hippo paths, where the hippos come out of the pool at night to feed, foraging as far as three miles for sweet young shoots.

At the bottom of the platform a dozen water monitors, some six-feet long, slither into positions that defend his or her portion of the bank, using the hippo paths as small highways.  The smaller monitors end up with the worst spots, constantly harassed in slow-motion chases by the larger lizards.  As I watch their typical reptile behavior, I think it’s lucky for us that the age of dinosaurs ended a long time ago.

Khwai River

 

On the far side of the river, specks in the distance, a huge herd of elephants splashes along the edge of a reed bed.  After I check for mambas, I lean on the rail of the platform to steady my camera.  I use the digital zoom to take a picture, already knowing it will be an extremely low-pixelated shot.  The elephants are in constant motion, appearing and disappearing in the reeds, so the photo turns out fairly blurry, but at least I have proof that those specks were really elephants.

Elephants on the far bank

On the way down from the platform I look for mambas wrapped around support posts, coiled under steps, and hidden in the framework of the flooring.  I scan for slithery movements in the brush and wait for someone else to climb in the Land Rover before I do.  I doubt the mamba has exchanged one lair for another, but still, you never know . . .

The viewing platform has its own GPS coordinates.  So if anyone wants to look at that mamba and reconfirm one more time that it’s really there, I can tell you exactly where to go!

Posted in Africa, Birds, Nature, Photography, Travel

A Surf of Birds

Red-billed Queleas

An Excerpt from my book:

On the far side of a large swath of golden grass the air shimmers, full of birds. As if by some sort of avian telepathy, Red-billed queleas rise and fall in curling waves, with wing-beats that sound like distant surf. Wave after wave washes across the clearing in front of us. It’s impossible to distinguish individual birds among the swell and tumble. Dust rises, perfumed by millions of feathers, hundreds of birds, each bird no bigger than my thumb. The flock settles into a tree. The branches of the tree droop as if suddenly laden with snow, then spring back up as the birds roll on.