Geoscience Reference
In-Depth Information
subset of species from nearby rainforests or grasslands. Forests that are more iso-
lated and those that have been highly fragmented are less species rich. Forests near
large rivers or in moist habitats can support a larger and more diverse population.
The fauna of the seasonal forests of the Neotropics today is the cumulative result of
millions of years of geologic, climatic, and biological events.
Mammals
Second only to the rainforest, more mammals inhabit the tropical seasonal forest
than any other biome. Seasonal forests in the Neotropics include a mixture of fami-
lies that evolved in North and South America, and others with origins from an an-
cient African connection. Mammals in these forests include marsupials and placental
mammals representing most terrestrial mammal orders and many families (see Table
5.2). These include opossums, anteaters, armadillos, sloths, monkeys, rodents, ungu-
lates, carnivores, and myriad bat species.
The marsupials of the Neotropics are all opossums. The opossum family is re-
stricted to the Americas, with one species in North America and about 70 species
in Central and South America. Those present in the seasonal forest include com-
mon opossums, woolly opossums, black-shouldered opossums, bushy-tailed opos-
sums, short-tailed opossums, mouse opossums, and four-eyed opossums.
Three-toed sloths can be found in seasonal forests, but their populations are in
decline because of forest fragmentation. Insectivorous anteaters and armadillos are
found in the forests of the Neotropics. All tend to be specialized feeders, eating
mainly termites and ants. The giant anteater roams the forest floor, and the taman-
dua hunts for ants in the trees. Anteaters will switch food preference during the dry
season, feasting on termites instead of ants, because of their higher moisture
content. Many armadillo species inhabit these forests, including the larger hairy
armadillo, the northern and southern naked-tailed armadillos, the nine-banded and
six-banded armadillo, and three species of long-nosed armadillo. The Chaco is
home to three endemic species of armadillo. Armadillos specialize in ants,
termites, and other forest insects. They too will shift their diets to a majority of
termites during the dry season.
Bats are found worldwide, and seasonal forests in the Neotropics contain a
great diversity. Bats are the most numerous mammals in the seasonal forest. All
Neotropical bats belong to the suborder Microchiroptera. These bats use echoloca-
tion to locate prey. Common bat families present in the seasonal forest include
sheath-tailed bats, leaf-chinned bats, mustached and naked-backed bats, fruit bats,
brown bats, vampire bats, and free-tailed bats. Bats are frugivores (fruit eaters), nec-
tarivores (nectar and pollen eaters), carnivores (meat eaters), insectivores (insect
eaters), sangivores (blood eaters), and omnivores (generalists). In the seasonal for-
ests, bats are crucial in regulating insect populations and pollinating flowers.
Primates are less abundant in the seasonal forests than the rainforests, as their
primary diet consists of leaves and fruit, which are available only seasonally. Black,
red, and mantled howler monkeys and capuchin monkeys are most common
