"Every creature on earth has approximately two billion heartbeats "

Iguazú, Argentina 2019

The Sun Magazine* has a section called The Dog Eared Page, where the publish works that have been from the January 2020 issue, is about hummingbirds and hearts.
published before.  This one,

"A hummingbird’s heart beats ten times a second. A hummingbird’s heart is the size of a pencil eraser. . .
"To drive those metabolisms they have race-car hearts that eat oxygen at an eye-popping rate. Their hearts are built of thinner, leaner fibers than ours. Their arteries are stiffer and more taut. They have more mitochondria in their heart muscles — anything to gulp more oxygen. Their hearts are stripped to the skin for the war against gravity and inertia, the mad search for food, the insane idea of flight. The price of their ambition is a life closer to death; they suffer more heart attacks and aneurysms and ruptures than any other living creature. It’s expensive to fly. You burn out. You fry the machine. You melt the engine. Every creature on earth has approximately two billion heartbeats to spend in a lifetime. You can spend them slowly, like a tortoise, and live to be two hundred years old, or you can spend them fast, like a hummingbird, and live to be two years old."

Then he makes a stark contrast.

"The biggest heart in the world is inside the blue whale. It weighs more than seven tons. It’s as big as a room. It is a room, with four chambers. A child could walk around it, head high, bending only to step through the valves. The valves are as big as the swinging doors in a saloon."

Most of us know so little about the natural world, a world we have tried to set ourselves apart from.  But, we too, are in the continuum from hummingbird to blue whale.  Our hearts are also four chambered.  Some specialists know a lot about hummingbirds or about blue whales.  But as profession of science has required more and more specialization, many scientists know a lot about a very small portion of the universe.  Knowing nature holistically is not the specialty of science, yet it's what we need, so that we understand how our actions affect everything else.  How extracting oil affects the air, the earth, the water, and all the living things near and far.  How it affects human health, wealth, values, morality.

Juneau,  Alaska 2008

*The Sun Magazine is a wonderful magazine with interviews, poetry, short stories, readers' stories based on a set theme, and other insightful writing.  It's also ad free.  You can see an article or two online without a subscription, but you can see all the titles over the years.