In The Night
In the night-time a tropical forest looks very different from the day-time. Under the trees everything is black, except where there are breaks in the leafy canopy. There the night sky glitters with an abundance of stars, some like shiny dust, others like glowing bluish eyes. These are details of the starry sky that we can't see when we are in a city so brightly lit that the stars are pale. These are details of the starry sky that we can't see when we are in a city so brightly lit that the stars are pale.
If we turn on our headlamps and shine the light up into the trees, we can clearly see the first and second layers of leaves, but above them the upper parts of the trees are dark shadows, broken by glittering patches of sky. Anything could be hiding up there.
On the ground there are also stars: numerous spider eyes reflecting back to us the lights of our headlamps. They are like a mirror of the starry sky. Except that we can't see the spider eyes unless we shine a light at them. Like mammals that are active at night, they have a special eye that collects light and reflects it, producing an "eyeshine," which is what people describe as "glowing eyes."
Some of the spiders are really big, but most are tiny with just very bright eyeshines. The big spiders include lovely furry tarantulas. One species gets to be as big as my hand, and has velvety black fur all over, even on the legs, but long silky reddish fur on the abdomen (see photos). Another species is even furrier, but golden-colored (photo). They usually live in holes in the ground, often right on the trails. We are glad they don't build webs across the trail like some of the smaller spiders. We are always walking into spider-webs because they are hard to see. These big spiders are not dangerous to us, but they do eat lizards and other small vertebrates, as well as insects. They, in turn, are eaten by coatimundis (photo), relatives of raccoons. They are one of many important parts of the food web of this forest, which is very complex.
One really bright eyeshine comes from a small hamster-sized mammal that perches on a vine. Its eyes bug out from a dark mask and its reddish-brown furry body trembles as we approach to get a better look at it. Its ears are thin membranes that twitch in our direction, and we are worried that it will run and hide before we get to see it clearly. We are in luck! The mammal is a pygmy opossum, what we call a Marmosa, and she is so frightened she just freezes in place, perhaps hoping we won't notice her and just go away. What can it be like for a small animal, out looking for dinner, to suddenly have bright lights shining from big animals that hover close and make strange noises? We take some photos and video and then leave her.
Our big surprise this night is a really big scorpion. It is dark, blackish in color, and has enormous curlicue pincers that reach out at us from a hole in a tree, just above our heads. As we move to see him from different angles, he moves to keep the pincers between us and his body. Not that he needs to protect his body from us-- he already has a big stinger on the end of his body, which he can wave in the air. He looks like a small lobster, and we have never seen one like him. He gets photographed and left alone! (video).
Later in the evening, as we walk farther down the trail, there are crashing noises in the treetops. As we turn our lights in the direction of the rustling of leaves, we hear cute little sneezing sounds. These are two kinkajous, leaping like slender cats from one branch to another. They travel high in the treetops, moving toward trees where they can eat sweet fruits or lick the nectar of flowers. They don't like our bright lights in their eyes, and the sneezing sound is to warn each other. The kinkajous are also raccoon relatives, but they have faces more like teddy bears, and lovely soft orange fur. Their tails are like an extra hand: what we call "prehensile." They can grasp a branch with their tail and avoid falling from a tree. The kinkajous pass quickly overhead and move off away from us.
This is a typical nightwalk, part of what we do to study the mammals on this island. We are again on Barro Colorado Island (BCI), in the middle of Gatun Lake, right next to the Panama Canal, down at the "bottom" of Central America, in that skinny little country called Panama. If you don't have a mental image of where we are, you might want to check the maps on our Rainforest Connection website. We are due south of New Jersey, about a 5-hour flight, or 2200 miles. It's one of the destinations for migratory birds from North America, a great place to stay during the winter months when it's hard to find insects in the north.
We will be your eyes in the forest, and report to you about our field season on BCI. We will write journal entries every few days, and if you wish to write to us, just use firstname.lastname@example.org.
If you would like additional information about some of the animals we mentioned above, check the Rainforest Connection website species accounts on coatimundis and pygmy opossums.
Jackie and Greg