the equator into the south torrid zone. The great Andean barrier
which crosses the republic from the south to north acts as a condenser
to the prevailing easterly winds from the Atlantic, and causes a very
heavy rainfall on their eastern slopes and over the forested Amazon
plain. High temperatures as well as excessive humidity prevail
throughout this region. Farther north, on the open llanos of the
Orinoco tributaries, the year is divided into equal parts, an alternating
wet and dry season, the sun temperatures being high followed
by cool nights, and the temperatures of the rainy season being even
higher. The rainfall is heavy in the wet season, causing many of the
rivers to spread over extensive areas, but in the dry season the inundated
plains become dry, the large rivers fed by the snows and
rainfall of the Andes return within their banks, the shallow lagoons
and smaller streams dry up, vegetation disappears, and the level
plain becomes a desert. The northern plains of the republic are
swept by the north-east trades, and here, too, the mountain barriers
exercise a strongly modifying influence. The low ridges of the Sierra
de Perijá do not wholly shut out these moisture-laden winds, but
they cause a heavy rainfall on their eastern slopes, and create a
dry area on their western flanks, of which the Vale of Upar is an
example. The higher masses of the Sierra Nevada de Santa Marta
cover a very limited area, leaving the trade winds a comparatively
unbroken sweep across the northern plains until checked by the
Western Cordillera, the Panama ranges and the Sierra de Baudo,
where a heavy precipitation follows. Farther south the coast ranges
cause a very heavy rainfall on their western slopes, which are quite
as uninhabitable because of rain and heat as are the coasts of
southern Chile through rain and cold. The rainfall on this coast is
said to average 73 in., though it is much higher at certain points
and in the Atrato Valley. As a result the coastal plain is covered
with swamps and tangled forests, and is extremely unhealthy,
except at a few favoured points on the coast. High temperatures
prevail throughout the greater part of the Magdalena and Cauca
valleys, because the mountain ranges which enclose them shut out
the prevailing winds. At Honda, on the Magdalena, 664 ft. above
sea-level, the mean temperature for the year is 82° F., and the
mercury frequently rises to 102° in the shade. These lowland plains
and valleys comprise the climatic tropical zone of Colombia, which
is characterized by high temperatures, and by excessive humidity
and dense forests, an exception to the last-named characteristic
being the open llanos where dry summers prevail. Above this
tropical zone in the mountainous regions are to be found all the
varying gradations of climate which we are accustomed to associate
with changes in latitude. There are the subtropical districts of the
valleys and slopes between 1500 and 7500 ft. elevation, which include
some of the most fertile and productive areas in Colombia; the
temperate districts between 7500 and 10,000 ft., the cold, bleak and
inhospitable paramos between 10,000 and 15,000 ft., and above
these the arctic wastes of ice and snow. The temperate and subtropical
regions cover the greater part of the departments traversed
by the Eastern Cordillera, the northern end of the Central Cordillera,
the Santa Marta plateaus, and the Upper Cauca Valley. They
include the larger part of the white population and the chief productive
industries of the country. There is no satisfactory record
of temperatures and rainfall in these widely different climatic zones
from which correct averages can be drawn and compared. Observations
have been made and recorded at Bogotá and at some other large
towns, but for the greater part of the country we have only fragmentary
reports. The mean annual temperature on the eastern
plains, so far as known, ranges from 87° F. on the forested slopes
to 90° and 91° on the llanos of the Meta and Arauca. On the
Caribbean coastal plain it ranges from 80° to 84°, but at Tumaco,
on the Pacific coast, within two degrees of the equator, it is only 79°.
At Medellin, in the mountainous region of Antioquia, 4950 ft. above
sea-level, the mean annual temperature is 70°, and the yearly rainfall
55 in., while at Bogotá, 8563 ft., the former is 57° and the latter
44 in. At Tuquerres, near the frontier of Ecuador, 10,200 ft. elevation,
the mean annual temperature is said to be 55°. The changes of
seasons are no less complicated and confusing. A considerable
part of the republic is covered by the equatorial belt of calms,
whose oscillations divide the year into a wet and dry season. This
division is modified, however, by the location of mountain ranges
and by elevation. In the Amazon region there is no great change
during the year, and on the northern plains the so-called dry season
is one of light rains except where mountain ranges break the sweep
of the north-east trades. The alternating wet and dry seasons are
likewise to be found on the Pacific coastal plain, though this region
is not entirely dry and vegetation never dries up as on the llanos.
Above the lowland plains the seasons vary in character according
to geographical position and elevation. The two-season division
rules in the departments of Santander and Antioquia, but without
the extremes of humidity and aridity characteristic of the eastern
plains. Farther south, at elevations between 800 and 9500 ft.,
the year is divided into four distinct seasons—two wet and two dry—the
former called inviernos (winters) and the latter veranos
(summers). These seasons are governed by the apparent movements
of the sun, the winters occurring at the equinoxes and the summers
at the solstices. The sabana of Bogotá and neighbouring districts
are subject to these changes of season. At higher altitudes long,
cold, wet winters are experienced, with so short and cold a summer
between them that the bleak paramos are left uninhabited except
by a few shepherds in the short dry season.
Fauna.—The geographical position of Colombia gives to it a fauna and flora largely characteristic of the great tropical region of the Amazon on the south-east, and of the mountainous regions of Central America on the north-west. At the same time it is rich in animal and plant types of its own, especially the latter, and is considered one of the best fields in South America for the student and collector. The fauna is essentially tropical, though a few species characteristic of colder regions are to be found in the higher Andes. Of the Quadrumana there are at least seventeen distinct species, and this number may be increased after a thorough exploration of the forested eastern plains. They are all arboreal in habit, and are to be found throughout the forested lowlands and lower mountain slopes. The carnivora are represented by seven or eight species of the Felidae, the largest of which are the puma (Felis concolor) and the jaguar (F. onca). These animals, together with the smaller ocelot, have a wide geographical range, and are very numerous in the valley of the Magdalena. Two species of bear and the “coatí” (Nasua) represent the plantigrades and inhabit the mountain slopes, and, of Pachydermata, the peccary (Dicotyles) and “danta” or tapir (Tapirus) have a wide distribution throughout the lowland and lower plateau forests. The Colombian tapir is known as the Tapirus Roulini, and is slightly smaller than the Brazilian species (T. americanus). There are deer in the forests and on the open savannahs, the rabbit and squirrel are to be seen on the eastern slopes of the Andes, and partly amphibious rodents, the “capybara” (Hydrochoerus) and “guagua” (Coelogenys subniger), are very numerous along the wooded watercourses. The sloth, armadillo, opossum, skunk and a species of fox complete the list of the more common quadrupeds so far as known, though it is certain that a careful biological survey would discover many others. The large rivers of Colombia and the lakes of the lowlands are filled with alligators, turtles, and fish, and several species of fish are highly esteemed by the natives as food. The saurians are represented on land by several species of lizard, some of them conspicuous for their brilliant colouring, and by the large “iguana,” whose flesh is considered a great delicacy. Among the ophidians, which include many harmless species, are the boa-constrictor, rattlesnake, the dreaded Lachesis and the coral snake. The “manatee” (Manatus americanus) is found in the Atrato and other large Colombian rivers.
In bird and insect life Colombia is second only to Brazil. The condor, which inhabits the higher Cordilleras, is peculiar to the whole Andean region, and is the largest of the Raptores. Among other members of this order are the eagle, osprey, vulture, buzzard, kite and hawk, with about a dozen species in all. Parrots and paroquets are numerous everywhere in the tropical and subtropical regions, as also the gorgeously coloured macaw and awkward toucan. The largest class, perhaps, is that formed by the astonishing number of water-fowl which throng the shallow lagoons and river beaches at certain seasons of the year. They are mostly migratory in habit, and are to be found in many other countries. Among these are the large white crane and small crane, the blue heron, the snowy-white egret, the roseate spoonbill (Platalea ajaja), stork, bittern and many species of ducks. The largest and most conspicuous member of this interesting family is the Mycteria americana, the gigantic stork so frequently seen in the Amazon valley, and even more numerous about the lagoons of northern Colombia. One of the best game-birds of the forest is the “crested curassow” (Crax alector), sometimes weighing 12lb, which feeds on arboreal fruits and rarely comes to the ground. Colombia also possesses many species of the beautiful little humming-bird, among which are the tiny Steganura Underwoodi and the sword-bill, Docimastes ensiferus, which were found by Mr Albert Millican on a bleak paramo 12,000 ft. above sea-level. One of the most interesting birds found in the country is the “weaver-bird” (Cassicus persicus), which lives in colonies and suspends its long, pouch-like nest from the end of a horizontal branch of some high, isolated tree. In regard to insects, what has been said of Brazil will apply very closely to Colombia. Mosquitoes, butterflies, spiders, beetles and ants are infinitely numerous, and some of the species are indescribably troublesome.
Flora.—The Colombian flora is richer in species and individual characteristics than the fauna, owing in part to its greater dependence on climatic conditions. It ranges from the purely tropical types of the lowlands to the Alpine species of the more elevated paramos. It should be remembered, however, that large areas of the lowland plains have only a very limited arboreal growth. These plains include the extensive llanos of the Orinoco tributaries where coarse, hardy grasses and occasional clumps of palms are almost the only vegetation to be seen. There are other open plains in northern Colombia, sometimes covered with a shrubby growth, and the “mesas” (flat-topped mountains) and plateaus of the Cordilleras are frequently bare of trees. Farther up, on the cold, bleak paramos, only stunted and hardy trees are to be found. On the other hand, a luxuriant forest growth covers a very large part of the republic, including the southern plains of the Amazon tributaries, the foothills, slopes and valleys of the Cordilleras, a larger part of the northern plains, and the whole surface of the Western Cordillera and coast. The most conspicuous and perhaps the most universal type in all these regions, below an approximate elevation of 10,000 ft.,
