Wildlife

A Battle of Dinosaurs: Crocs vs. Birds

A YELLOW-BILLED STORK LOOKS ON AS HIS COUSIN IS CAPTURED BY A CROC.

The rains ended months ago, starving the Msicadzi of its flow and surrendering it to dust. It wouldn’t be much longer before the river was gone. For now, all that was left was a pool, a hundred feet long and a few feet deep. In it thousands of fish were trapped, from tiny fry to fierce catfish the length of a man’s arm. Ancient creatures assembled for the feast, like something out of the Cretaceous: herons swooped overhead like pterodactyls, while storks were squabbling velociraptors. And beneath the water, the pool churned with huge, silent, sharp-toothed beasts, whose lineage has persisted on earth for over 200 million years.

A CROC SWALLOWS A FEW TINY FISH THAT IT HAS JUST CAPTURED, AS A MARABOU STORK STANDS BY.

Twenty-five years ago, the Mozambican civil war ended, leaving Gorongosa National Park’s large mammal populations in ruins. Crocs seemed to pull through unscathed, growing in number and in body size. Perhaps this was because the lions and jackals that they would have competed with were gone, or maybe their aquatic habits allowed them to escape the poachers. Possibly, local legends saved them: in some of the communities around the park, crocodiles are taboo to kill, thought to be reincarnations of human spirits, perhaps family members. Whatever the reason may be, as the war raged on here in the 1970s and 80s, Gorongosa’s crocodile population climbed to what might be one of the highest densities in Africa.

A MARABOU STORK WATCHES A CROC SWALLOW THE FISH IT HAS JUST CAUGHT. THE STORK WAITS FOR AN OPPORTUNITY TO CAPTURE ANY FISH THAT THE CROC MIGHT DROP.

Now, the war was long over, but the dry season was tightening its grip. The desperation of some species, like fish confined to ever-shrinking pools, led to opportunities for others: birds and crocodiles gathered together at the lingering Msicadzi River in a tense truce, trawling captive fish from dawn to dusk. From my camouflaged hide on the sandy bank, I photographed the spectacle as the rising sun glinted off the water.

The Msicadzi River flows into the Sungue Channel, across a vast floodplain and then into this lake. Lake Urema is a shallow Rift Valley Lake that sits in the depression between the higher Rift escarpment on either side.

Outside the blind the air crackled with birds. Yellow-billed storks clacked their beaks as they chased each other from prime fishing spots. Hamerkops cackled, seemingly too loud for their small bodies as they gathered in small groups to practice an odd leapfrogging social ritual. Pied kingfishers twittered outside of their burrow, bickering over the best perch from which to watch for fish before they began their hovering hunt.

A YELLOW-BILLED STORK WALKS IN FRONT OF A CROCODILE AS THEY SEARCH FOR THE SAME PREY: FISH.

 

Along the shore, white-backed pelicans clustered disinterestedly, their unwieldy heads like levers on a fulcrum as they swung their beaks back to groom. Then suddenly, at a silent signal three dozen of the huge birds dog-piled into the water, frantically gulping invisible prey from just below the surface. After a few moments they heaved back to shore, flipping back their yellow throat pouch to swallow their quarry. Then they plunked back down to wait.

A half hour passed as yellow-billed storks strode to and fro, their heads swaying like a metronome, skimming their long bills in the water for fish. The truce was apparent: to the feeding storks, the crocs were like rocks, avoided but not feared. Tiny egrets fluttered and dipped just in front of a crocodile’s maw, snagging fish that were startled by the reptile. A croc lunged at a fish, slapping the water suddenly with its jaws, and the birds nearby leaped and dropped like rebounding water droplets, then resumed their hunt as though nothing had happened.

A WHITE-BACKED PELICAN GROOMS ITSELF ON THE SHORES OF THE MSICADZI RIVER.

 

And suddenly, there was a thundering splash and the pelicans belly-flopped back into the water. This time, the birds had barely broken the surface when they jolted away as if shocked by an electrical current. Some fled, sailing up and over the trees. Others stood on the shore, wings extended nervously, glancing side to side, tense as a coiled spring.

One pelican remained in the black glassy water, floating askew, its white wing in the air. Lifelessly the pile of whitish feathers glided toward the nearest bank. It was a few moments before I realized what had happened, when a blackish sawtoothed ridge breached the surface. He had been waiting for them – a male crocodile the length of a car, ancient, impossibly silent. The storks fished on, unfazed, while the pelicans still stood stunned.

Was it a coincidence that the croc was waiting where the pelicans had landed before? Or was he able to observe past events and predict a future outcome? It may have been the latter, as recent research has shown that crocodilians are much more intelligent than once thought. American alligators, for example, decorate their heads with twigs and sticks and then lie in wait for birds that are eagerly seeking nesting material. As soon as a bird approaches, the alligators lunge at their prey. Incredibly, this behavior peaks during bird nesting season, when birds are most likely to be looking for sticks.

AFTER THE PELICANS DIVE INTO THE WATER, ONE IS LEFT FLOATING ASKEW.

 

That luring behavior was the first time tool use has been documented in a reptile. They may seem like dumb brutes, but crocs are becoming known for their interesting and intelligent behavior: they camouflage themselves with mud and vegetation and then wait in ambush for prey; they communicate with one another using vocalizations, infrasound, and slaps; they play, sometimes even with other species, like otters; there have been reports of crocs bonding with humans that rescued them; they can hunt cooperatively, with some crocs driving prey into the waiting mouths of their companions; and finally, translocated crocodilians have been recorded navigating hundreds of miles to get back home.

THE HUGE MALE CROCODILE WORKS TO SWALLOW HIS NEWLY CAUGHT WHITE-BACKED PELICAN ON THE SHORES OF THE MSICADZI RIVER.

 

When I’m in the field, setting up mist nets along rivers to catch bats or crossing floodplain channels on foot, I don’t like to admit to myself that these beasts lurking near me in the deep are as smart as they are fierce, though it appears to be true. We’ll never know exactly what this big croc was thinking when he ambushed the hunting pelicans, but it’s possible that he knew they’d be back. With pelican wings dangling from the corners of his mouth like an odd winged head, the croc hauled half out of the water and began the task of swallowing his prey. Throwing his head back and forth, he tried to guide the limp bird down his enormous throat. But with its long wings and heavy head, the pelican flopped about, catching in the corners of his mouth and refusing to go down. It wasn’t long before the smaller crocs realized what was going on. They surrounded him, snapping at his jaws, tossing sharp teeth, seizing mouthfuls of feathers and tossing them back like potato chips. The big croc shoved through them and swam downstream, wings still dangling, five or six smaller crocs in pursuit.

THE HUGE MALE CROCODILE TRIES TO SWALLOW ITS PELICAN PREY WHILE SMALLER CROCS ATTEMPT TO STEAL IT FROM HIM. HERE, ONE OF THEM HOLDS THE PELICAN’S YELLOW BILL IN ITS MOUTH.

For the next two hours, I watched the croc swim steadily up and down the short stretch of river, pelican wings dragging. Each time he gained distance from the others, he paused, gulping desperately. And each time, a wing got in the way. His pursuers caught up and surrounded him while he seemed to grow evermore desperate. Eventually, a small croc gripped the pelican’s yellow bill, and with a fierce tug pulled the bird’s head from its body. In seconds, the bill had disappeared down the small croc’s throat. It was a hidden blessing for the big croc: his food more streamlined, he gulped the headless bird down, its wings folding backward as he swallowed it whole.

Without pausing to relish his victory, he slipped into the pond. The other crocs went back to hunting fish. The storks continued sweeping the water. The pelicans resumed their grooming. The truce was back on, for now.

A marabou stork takes a drink at sunset in the Msicadzi River.
The dry season Msicadzi River at dusk, lined by fever trees.

Jen Guyton is an award-winning photographer and an ecologist with a passion for wildlife conservation and science communication. She is a National Geographic Explorer and a National Science Foundation Graduate Research Fellow, with a masters degree in Ecology and Evolutionary Biology from Princeton University, where she is currently pursuing her PhD. She has traveled on five continents, including many years of working on wildlife and conservation projects in Africa. Jen currently studies mammal ecology and conservation in Gorongosa National Park, Mozambique. Follow her on Facebook, Twitter and Instagram, and check out her website.

 

For more information on crocodile intelligence, see the links below.

https://www.sciencedaily.com/releases/2013/12/131204182433.htm

https://phys.org/news/2015-02-crocodiles-wanna-fun.html

http://www.islandpacket.com/news/local/news-columns-blogs/untamed-lowcountry/article33549558.html

http://www.tandfonline.com/doi/abs/10.1080/03949370.2012.744358

http://animalbehaviorandcognition.org/uploads/journals/5/04.Dinets_FINAL.pdf

http://www.tandfonline.com/doi/full/10.1080/03949370.2014.915432?scroll=top&needAccess=true

Facebook: www.facebook.com/jenguytonphoto Instagram: www.instagram.com/jenguyton Twitter: www.twitter.com/jen_guyton
  • Claudia Guyton

    This is truly amazing, brings the wild life in your home. Thank you

About the Blog

Researchers, conservationists, and others share stories, insights and ideas about Our Changing Planet, Wildlife & Wild Spaces, and The Human Journey. More than 50,000 comments have been added to 10,000 posts. Explore the list alongside to dive deeper into some of the most popular categories of the National Geographic Society’s conversation platform Voices.

Opinions are those of the blogger and/or the blogger’s organization, and not necessarily those of the National Geographic Society. Posters of blogs and comments are required to observe National Geographic’s community rules and other terms of service.

Voices director: David Braun (dbraun@ngs.org)

Social Media