A Sample Walk in a Panamanian
Rain Forest
To help you get a feel for how a rain forest walk might
unfold, I have chosen to take you to southern Panama.
We begin our walk along the muddy forest trail, being
careful to listen and look (plate 4- 11). At several places
we can’t help but notice lines of leaf- cutter ants (genus
Atta), their well- worn trails crossing ours (plate 4- 12).
Leaf- cutters are abundant throughout the Neotropics
and occur nowhere else on Earth. We notice that the
ants come in various sizes, and some have impressively
large mandibles. Most of the ants are bearing leaf
fragments, neatly clipped in a circular pattern. The
leaves won’t be eaten by the ants but will, instead, be
taken to a vast underground colony, where they will be
used to cultivate a fungus species that the ants farm.
It is the fungus that is the real food of the ants, and so
their alternative common name is fungus garden ants
(chapter 10).
Rain begins, soft at first, soon more intense. We are
surprised at how little of it seems to wet us. The dense,
leafy rain forest canopy intercepts most of the rain. Soon
the shower ceases, though for a while the steady dripping
from the canopy makes it seem as if it is still raining. A
loud sound, not too distant, indicates that a big branch,
or perhaps a full- size tree, has fallen. Tree falls during
storms are not only common in tropical moist forests
but essential to the overall ecological functioning of the
forest (plate 4- 13). Light gaps created by falling trees and
branches will be discussed in detail in chapter 7.
A small, richly brown animal resembling a tiny deer
crossed with an oversize, tailless mouse tentatively
prances across the trail, pausing in a light gap just long
enough for us to get a binocular view of it. It’s an agouti,
in this case a Central American Agouti (Dasyprocta
punctata; plate 4- 14), a common fruit- eating rodent
unknown outside of the Neotropics.
We continue slowly along the forest trail, stopping
frequently to look and listen. Looking up we notice a
large bird moving through the canopy. It lands, and
we get a good look at one of the gaudiest and most
distinctive of the hundreds of Neotropical bird species.
It’s a Yellow- throated (also called Black- mandibled)
Toucan (Ramphastos ambiguus; plate 4- 15). Toucans
and their close relatives toucanets and aracaris are
among the numerous birds unique to the New World
tropics. They feed on many items, ranging from eggs
and baby birds to their more common diet of various
fruits.
Continuing along, we hear an odd but distinctive
snapping sound in the dense understory beside the
trail. A small bird appears, its wings whirring as it
lands on an understory branch. Patience affords an
eventual good look. There are several of these birds,
and they periodically begin snapping and whirring,
their throat feathers puffed out. The birds are male
Golden- collared Manakins (Manacus vitellinus; plate
4- 16). Manakins gather together in forest areas called
leks, areas of courtship behavior. The objective of the
birds’ collective behaviors is to attract a female to mate
with one of them. Lekking behavior is common among
manakins and cotingas and will be discussed much
more in chapters 10 and 15.Plate 4- 12. Usually the first sign of leaf- cutter or fungus garden
ants that a visitor sees is a line of leaf fragments moving across
a forest floor or, in this case, a log. A closer look will reveal the
ants that are carrying them after they are clipped from the
trees. Photo by John Kricher.Plate 4- 11. Let’s head into the forest and see what’s in it. Photo
by Bruce Hallett.
62 chapter 4 finding animals in rain forest