Webmaster's note: This report comes from Dr. Louis Jacobs, president of ISEM.
The seaward view from Cerro Tortuguero.
On Saturday morning, Diana, Kent, and I (Louis) went on a final nature voyage in the Tortuguero waterways with Daryl, our guide. We felt lucky to see river otters again, two days in a row. Daryl guided the boat through the narrow and hyacinth-clogged bayous to a primary Raphia palm swamp.
It was a primordial scene, replete with the howls of monkeys and calls birds, the splash of caimans, the stealth of herons and rails, the dive-bombing of hummingbirds, and the dash of kingfishers. The cacophony of unfamiliar sounds was layered on a slow current of quiet, on our own breathing as we drifted on the swamp-black and glassy-smooth water, slipping in and out of reaching branches. It ended all to soon.
A caiman in the rivers near Tortuguero.
The reason for Kent and me to leave Tortuguero was to investigate the potential for paleontological studies into the incredible biodiversity found in Central America. Of course, it is a long shot to find fossils in the forest-dominated tropics because rock outcrops of the appropriate age and composition are just too rare. Should they form from a landslide or from flood, the jungle claims them in short order, roots and soil destroying the fossils, green plants and litter obscuring the surface. But if the luck of the rocks is right, a few fossils will be found and they will have a story. That is the case for every Central American country, and that is the way it is in Costa Rica.
Our first step was to go to the natural history museum in San Jose to see the fossils on display there. That would be on Sunday afternoon. On Sunday morning, May 13, we left bright and early for Braulio-Carillo, the rain forest preserve outside of San Jose. There is a cable stretched through the canopy, allowing a view of the upper layers of this tropical ecosystem. Arriving just before seven, the rangers told us there was a big and very rare animal in the stream near the road. We walked over. It was a tapir!
Tapir observed at the Braulio-Carillo preserve
Here was one of the most secretive of forest mammals, barrel-shaped, with short legs, and weighing up to three-hundred pounds. There it sat in the water, like a dog, cooling its gray-brown body, its head held up, but its proboscis protruding occasionally to reach the surface of the water for a drink, sending small concentric ripples fleeing from the tube of its nose. It rested for several minutes, but our fear of its leaving made it seem like it was there much longer. Finally it rose slowly and walked toward the left bank, raising its four-toed front feet high above the water surface, then gingerly placing them down, the three-toed hind feet following in cadence. It reached the greenery of the shore and disappeared immediately, invisible in the vegetation. The understory of silence reigned again as the rush of excitement drained from our ears.
Then on the trail Kent spied a small, slim snake, a mussurana (Clelia clelia), its dark body contrasting with its white neck ring. The mussurana is a non-venomous snake that makes a meal of venomous snakes. It would be the first of two snakes we would see that morning, the second being an eyelash viper (Bothriechis schlegelii), so-called because of the crusty protruding scales above its unforgiving reptilian eye, coiled on the fork of a tree, fat with the anole lizard it had eaten.
While suspended from the cable through the canopy, a large tree laden with epiphytes, the mosses, ferns, and air plants, such as bromiliads that cling to a host tree and orchids whose roots dangle in the humid air and infiltrate the humus that rots on thick boughs, crashed to the ground. We were not there to witness the event, yet we heard it, answering to our satisfaction the question: If a tree falls in the wilderness, and there is no one there to hear it, does it make a sound?
We saw many more orchids and bromiliads at the Lankester Gardens of the University of Costa Rica that afternoon, after which we visited the natural history museum. There on display were bones of fossil elephant relatives and of a large tapir- or hippo-like herbivore called a toxodont, which probably had a niche similar to those modern river-frequenting beasts. On Monday we went behind the scenes to see the part of the collection not on display. The remains were scrappy and rare, as we knew they would be. But the list included horse, coyote, three kinds of elephant-relative, tapir, horse, giant ground sloth, and a giant armadillo-like glyptodon. There were also a few samples of fossil leaves and of sharks.
Our next task was to determine the geological context of the fossil localities that yielded the bones, so we headed northwest toward the Pacific Ocean. It is clear that the fossils are found along the drainages of large rivers where erosion can expose them and where sediment-choked Ice Age rivers left bone-inclosing sediments along stream channels.
After a long, slow drive in the dark, over rough unpaved roads, our night was spent in the cool cloud forest of Monteverde at the El Sapo Dorado Hotel, in reference to the colorful frogs, now endangered, that used to inhabit the region in abundance.
In the morning we saw the lush jungle, surrounded by deforested mountain slopes. The epiphytes were more abundant and diverse than in the rainforest of lower elevations. Trees grew upon trees. The epiphytic trees supported their own epiphytic ecosystems, and they in turn theirs. More species live in this forest than in any other in the world. Orchids abound in variety, from the world's smallest known species to those with flamboyant blossoms lasting only a day to those with the siren-fragrance of chocolate. White faced capuchins danced through the trees while Alfaro's pygmy squirrel shied away on the opposite side of the trunks, out of view of the predaceous, carnivorous monkeys. We saw birds. We saw the orange-breasted trogan, whose lowland relative, the slaty tailed-trogan, we had seen at Tortuguero. We saw colorful birds with strange names like euphonia and chlorophonia and motmot. There were those with more mundane-sounding bird names like the yellowish flycatcher, which we saw sitting a nest. Also on a nest up in a tree we saw a big black guan, a relative of the chicken. We heard the call of the three-wattled bell bird, but we never saw it. Striking beyond all the rest, the image of the forest that clings to the mind like the mosses on a dripping trunk is the delicate and shimmering, ever-changing iridescent colors of the long spectacular plumage of the resplendent quetzal. We saw both male and female, the male with a head crest, magnificently elongate tail feathers, and bright red breast. He sat holding golden beetles, almost like lost broaches, in his white beak, then flew into the hollow in a dead tree to feed his nestling. Both the male and female care for the young in this species, and while the female lacks the long tail feathers and some of the flamboyancy of the male, she is a spectacular bird in her own right.
Our trip was complete, but the image of the quetzal kept me thinking, as it must have the Precolumbian inhabitants of this fascinating countryside. It strikes me as strangely amusing that the quetzal, its spirit distilled through Mayan deity, has become the namesake for the largest animal ever to fly under its own power in all the history of the Earth, the pterosaur Quetzalcoatlus. From my perspective as a paleontologist, I find it strangely amusing that, with the exception of the toxodon, the Ice Age animals found in Costa Rica are those that lived at the same time around my home in Texas. Yet now, and in all probability then, the rainforest and cloud forest presents the world with a unique situation, a panoply of species mixed from here and there, from North America and the South, and with its own unique species. Add to that the history of origin of the lands that make Central America, the very ancient roots of some of its modern plant and animal inhabitants like tree ferns, caimans, and crocodiles. And then there are the rare and much more ancient records of life, their ages measured up to hundreds of millions of years ago - what was their original homeland?
We began with sea turtles and their migrations around the sea, the research being done by Dana and Diana. Sea turtle origins take us back a hundred million years, to a time when the southern Atlantic Ocean as we know it had its beginnings. How strange this all is, and how unique this place. This is a place of uniqueness on a scale hard to fathom. It is not so much a Garden of Eden, although it acts as one for its teeming multitude of endangered species. It is much more than that when viewed through time on the scale that moves our Earth, manifested in the results that the confining time scale of human life presents to us. This place is not so much a place, but rather a dynamic mingling of Edens, of places that merged and times that changed, of volcanoes and migrations and ocean seaways across the isthmus. Perhaps the most compelling aspect of this mingling of Edens is that we are now inhabitants of this very garden, this caracature of our Earth. We are its sole caretakers for all the time that will ever matter to humans.
How good a gardener can we be?
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