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The tiny bug needs a rest. Almost any spot will do. Her world—100 million years ago in Myanmar—is not one of vast seas, towering mountains or broad deserts, but a damp and gnarled landscape of branches, trunks and leaves that provide a seemingly infinite number of places to alight. She just needs a few moments before taking off again to follow the carbon dioxide trails of other creatures filled with vital, rushing blood.
Her forays in search of food aren’t usually this much of an ordeal. Today, wind has been the problem. Strong breezes have come with another day of drizzle, a chaotic and lilting series of gusts that have required extra effort with every flap of her transparent wings and every maneuver through the vegetation. She cannot hear the sound, but all day the needle-covered branches of the forests’ conifers have been creating a soft and prolonged susurration as the storm slowly expends itself. She can’t wait for it to be over. For such a small life, food is burned quickly and hunger is a familiar sensation. If she doesn’t eat every four days, she’ll perish. This is the third day of rain and interfering winds. She can’t count on eating tomorrow. The mosquito must try today.
At least these forests are rife with sanguine creatures of all sizes. Some are small enough to see her approach, while others might as well be mobile mountains of flesh. There’s always a warm body in these Cretaceous woods. Her latest meal, taken on the last sunny day before the unpleasant mist set in, was a broad-headed amphibian clinging to a lofty branch—Yaksha. The amphibian had evolved into an ambush-based lifestyle that chameleons would later copy, waiting and watching for unassuming invertebrates to get too close. Pull focus, move slow, and blap—the amphibian’s spring-loaded tongue can shoot forward to adhere to the creature’s unfortunate prey and reel it back toward small jaws set with tiny teeth.
Yaksha might have eaten the little mosquito if she had flown in from a different direction, but she was lucky that day, and the little syringe-mouthed insect was able to gently land on the arboreal amphibian’s soft skin, plunge her mouth into the pliant flesh and drink her fill, distending her abdomen with vibrant and translucent red as she heavily flew off to digest.
Her takeoff had to be awkward. There’s no dignified way to take off fatted with so much blood that she’s three times heavier than before she started sipping. Every time she finishes slurping, she begins a frantic flapping of her little wings, spreading the tiny wisps of her legs across the body of her unwitting host to hopefully spring into the air undetected. In a split second she’s flying, wings humming at 800 beats a minute to carry the precious fluid inside of her. That was a good day, and she was nourished enough to lay eggs in a shallow pond formed in a round dinosaur footprint. Now she’s much lighter, practically empty of the food she needs. Despite the drops falling everywhere and wind that might blow her off course, she has to hunt if she’s going to survive through tomorrow. She stretches her jointed legs over the bark of the tree, as she’s done hundreds of times before, and vaults into the air.
She doesn’t get far before an unexpected gust pushes her back toward the conifer she has just taken off from. And this time, she’s unlucky. The breeze sends her tiny body tilting and shifting sideways into an oozing, golden mass of resin. She’s stuck.
When the Earth Was Green: Plants, Animals and Evolution’s Greatest Romance
A gorgeously composed look at the longstanding relationship between prehistoric plants and life on Earth.
Dinosaurs can be hard on trees. The biggest ones, incredible long-necked herbivores, scrape against the bark, snap branches and even topple entire trunks as they move through these conifer-filled woodlands. The creatures are sometimes clumsy as they navigate their world, completely unaware of the consequences of each footstep and every scrape against the rough bark as they pass through the woods. The forest is full of dinosaur-sized trails that the titans prefer to walk through, the open spaces further trampled by all the other species that take these convenient footpaths. But even the most regal and impressive dinosaur sometimes has an itch to scratch. Not long before the little mosquito supped on amphibian blood, a huge sauropod wandered by and rocked back and forth on its column-like limbs, scratching its louse-bitten hide against the rough conifer bark. The biters are too tiny to defend against, tucking into the various cracks and crevices of the dinosaur’s scaly skin, and there’s little an irritated dinosaur can do but try to alleviate the itch. And in that moment, as the dinosaur scratched its hide against the tree’s rough bark, it opened a wound on the conifer. Just as the trees evolved bark to help protect their more vulnerable tissues inside, the dinosaur evolved thick, pointed osteoderms along its flanks—bony armor floating in the skin that could break the tooth of a carnivore that gets too bold. As the dinosaur itched, the spike-like osteoderm scratched over the tree’s trunk and caught on the bark, the keratin-covered armor sawing into the outer layers. The tree’s response was involuntary. It could feel no pain, but instead the plant’s tissues began to respond to the insult. As the dinosaur ambled away, great tail swaying behind its multi-ton body, golden goop began to trickle out of the tree where the wound had just been cut.
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An open gash leaves a tree vulnerable. The dinosaur had unknowingly exposed the inside of the tree to fungus, wood-chewing insects and other hazards that could take hold in the wood and slowly make the tree’s own body hostile to itself. Even a relatively superficial opening could be an entry point to living things that would consume the tree from the inside out. Resin evolved as a kind of natural bandage, able to cover over and harden until the tree’s slow growth could replace the damaged tissue with a new protective layer. Following the scratch, the tree’s resin dripped, oozed and sealed the wound, longer threads of the golden liquid trailing down the bark and a few dropping onto the forest floor. At least the ooze was performing as intended. Sometimes the resin can build up among the cells between the wood and the bark, and if enough of the sticky goo accumulates, the tree trunk can burst from the built-up pressure.
Such catastrophic malfunctions aside, most of the time conifer resin slops over the gash and remains tacky for days afterward. Creatures climbing over the trunk and even debris carried by the wind can get stuck in the natural trap. Where conifers grow along the coasts, even seashells sometimes get blown into the goop.
The sticky stuff that had suppurated from the tree’s bark will coagulate and solidify in time, but not soon enough for the mosquito. She was blown right into the center of it, too small to pull herself free from the mess. She struggles. She has to. She has to try to pull herself free with every twitch and flutter her little body can muster. She can’t feed and she can’t drink stuck to the tree. But for something so small, the resin is fatal. The thrashing of her final moments becomes recorded in the resin itself, her wings outstretched among tiny bubbles of oxygen stirred into the yellow mire. In a few moments, she’s encased. She can’t breathe, the golden liquid a barrier between her and the outside world that deprives her of the vital oxygen the mosquito needs. She is part of the tree now.
The same story is playing out all over the world, completely mundane moments of an exceptional time. In woodlands much like this one in prehistoric Myanmar, from equatorial forests to those that survive through the long dormancy of polar nights, pieces of Cretaceous life are becoming encased in resin. A gash in a pine near a beach suppurates golden glop that catches the vacated shell of an ammonite kicked up by a gust blowing over the sand. Chewed-up feathers of a nesting toothy bird become stuck in the fresh resin of the tree hosting the nest, trapping the larvae of feather-eating beetles along with the decomposing plumage. A big-eyed lizard takes a few unwary steps up a tree trunk and becomes trapped in a sticky puddle, soon covered over and encased. This is the Cretaceous Resinous Interval.
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Between 84 million and 137 million years ago, resin-oozing conifers thrived across the planet. The mosquito’s fate has been played out over and over again, and will for millions of years more, as gashes in conifers have seeped and dripped. Each dollop offers a unique opportunity for fossilization. In the case of the little mosquito, the resinous drop she is enclosed in will eventually fall to the forest floor and be covered over with sediment, folded into the soil. Streamwater laden with minerals will wash over the concealed resin, percolating through microscopic cracks to replace her tissues and fossilize her body within the yellow goo. Her form is now preserved as an exact, intricate copy, ready to survive tens of millions of years of solitude until the rock that formed around the amber erodes away to let sunlight touch the ancient resin once more.
From When the Earth Was Green: Plants, Animals and Evolution’s Greatest Romance by Riley Black. Copyright © 2025 by the author and reprinted by permission of St. Martin's Publishing Group.
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