Category Nature Science & Wildlife

No plants or animals can survive if they have no water at all for a long period, but in the desert regions of the world many living things have adapted so that they can thrive with very little water. Deserts are places with very little rainfall, but they are not always hot. Some are very cold at night or in the winter. Animals and plants have to be able to deal with extreme temperatures as well as a lack of water.

On average, a human can only go for an average of three days without water depending on the climate because the human body loses a substantial amount of water through sweating, breathing, and excretion. Every drop of sweat, exhaled breath, and wet excrete increases the chances of death of any desert animal through dehydration. There are a few animals that can survive for years without drinking any water. Some of the popular examples include the desert tortoise, kangaroo rat, the thorny devil, water-holding frog, African lungfish, and desert spade-foot toads.

Kangaroo Rat

The kangaroo rat of North America is one of the most specialized animals living in the desert environments and can go for its entire life without water. The small rodent gets its name from is long hind legs (similar to the Australian Kangaroo) that enable it to leap long distances as they search for food and water. Some of the adaptations to the arid environment include large cheek pouches that are lined with fur as opposed to saliva which enables the rodent to carry seeds without losing much-needed moisture. Other adaptations, such as highly specialized kidneys with additional tubules, help them in the conservation of water in the body through the extraction of water from urine. The urine of a kangaroo rat is about five times as concentrated as human urine. The kangaroo rat has an oily coat and does not sweat which goes a long way in conserving water in the body. In addition to that, kangaroo rats feed on seeds that are safely hidden in burrows. The seeds once consumed are metabolized to yield energy and water.

Water Holding Frog

The water holding frog (Cyclorana platycephala) is commonly found in Australian desert areas and has truly unique adaptation mechanisms to the harsh arid environment. During wet seasons, the water holding frog lives like ordinary frogs and then burrow into the soil when dry conditions set in to escape the hostile conditions. The frog has the unique capacity to absorb significant amounts of water through its skin which is then stored in its bladder and body tissues. Once the frog burrows into the soil, it encloses itself in a cocoon made up of its skin to keep from losing water. While in this condition the frog feeds on its skin and can stay in this condition for several years.

Thorny Devil

The thorny devil (Moloch horridus), which is also commonly referred to as the thorny dragon, is typically found in desert areas in Central Australia. The thorny devil captures rainfall and dew during drier conditions through layered scales on its body that have a hinge which enables it to trap moisture and water droplets between the scales. The collected water is then transported under the skin to the mouth. The process is enabled by tongue movements that create the needed pressure to draw water to the back of the mouth.

The Desert Spadefoot Toad

The spadefoot toad (Scaphiopus couchi), which was recently discovered in the Colorado Desert, has some of the greatest adaptations to desert conditions. These animals have managed to survive in a few isolations such as the edge of dunes and dry washes due to their unique environmental conditions. Spadefoot toads living in the dunes burrow into the permanently wet layer in the sand and remain there for the whole dry period. Others bury themselves beneath dense vegetation. Adult toads retain several layers of partially shed skin which reduce moisture loss by forming semi-impermeable membranes and can remain in that condition for years. The high osmotic concentration greatly increases its ability to retain water and perhaps even extract moisture from damp conditions. These toads also exhibit an extremely accelerated growth rate. Their eggs take less than 48 hours to hatch, and within ten days the tadpoles develop legs. In less than three months, the young toads grow to half the adult size.

As in most other habitats, the colouring of animals in the rainforest is very varied. Some are brilliantly coloured, to attract mates or to warn predators that they are poisonous. Other creatures have green or dark colouring to camouflage them amongst the vegetation. This hides them from their enemies and enables them to creep up on their prey unseen.

Parrots, macaws, parakeets… these rain-bowed tropical birds put to shame the brown and gray birds that are so common in Illinois and Chicago. Even Chicago’s brightest birds—cardinals, blue jays, gold finches—are vibrant, but single-colored. Why are bright and multi-colored birds so common in tropical rain forests, and nowhere to be found in temperate climates like Chicago? Do the changing seasons make bright birds sitting ducks in the winter? Do jungle birds eat bright berries and fruits instead of brown and black seeds? What gives?

We can eliminate one option right away: a parrot’s color has nothing to do with its diet. While a flamingo gets its pink color from the food it eats (brine shrimp and blue-green algae) and a cardinal is red in part because of the seeds in its diet, a parrot’s color is determined by its genes. The incredible colors of the blue-and-yellow macaw do not come from tropical mangoes and imported blueberries.

It must be some other quality of the tropics that creates brighter birds: is it the rainfall? The year-round high temperatures.

The truth is that tropical birds don’t tend to be more colorful. Dr. Nicholas Friedman of the Okinawa Institute of Science and Technology explains, “If you look at birds in the tropics, there are a lot of colorful birds that stand out. But there are really more species in general there and there are just as many more of the little brown ones”.

In other words, the tropics are much more diverse in general than temperate or dry climates. The rainfall and year-round high temperatures contribute to rainforests having many more animal and plant species than other places. Of these many more animal species, some are brightly colored birds, but there are even more species that are plainly colored. The birds that are exported from the rainforests for zoos or as pets are the brightest birds, and these are the tropical birds that we in Chicago are familiar with. This leads to the overall impression that birds from the rainforest are more colorful as a rule.

The many habitats to be found in rainforests can be thought of as layers. In real forests, of course, these layers overlap each other a good deal.

Emergent Layer

These giant trees thrust above the dense canopy layer and have huge mushroom-shaped crowns. These trees enjoy the greatest amount of sunlight but also must endure high temperatures, low humidity, and strong winds.

The emergent layer consists of the tallest trees, with umbrella-like branches poking through the mass of leaves below. In this layer live free-flying birds and bats, including birds of prey.

Canopy Layer

The broad, irregular crowns of these trees form a tight, continuous canopy 60 to 90 feet above the ground. The branches are often densely covered with other plants (epiphytes) and tied together with vines (lianas). The canopy is home to 90% of the organisms found in the rain forest; many seeking the brighter light in the treetops.

The tree canopy consists of the leaves of mature trees. Their tops spread out to reach as much of the light as possible. As well as birds and fruit bats, monkeys and squirrels live in this layer, feeding on the fruits, nuts and leaves of the trees in the canopy.

Understory
Receiving only 2-15% of the sunlight that falls on the canopy, understory is a dark place. It is relatively open and contains young trees and leafy herbaceous plants that tolerate low light. Many popular house plants come from this layer. Only along rivers and roadways and in tree-fall and cut areas are sunlight sufficient to allow growth to become thick and impenetrable. 

Very little light filters through the leaves of the canopy. In the mid-zone, creepers called lianas hang in great ropes among the trees. Here there are monkeys, squirrels, birds and bats again, but also some snakes and tree frogs.

Forest Floor

The forest floor receives less than 2% of the sunlight and consequently, little grows here except plants adapted to very low light. On the floor is a thin layer of fallen leaves, seeds, fruits, and branches that very quickly decomposes. Only a thin layer of decaying organic matter is found, unlike in temperate deciduous forests.

The forest floor is very dark. Larger mammals, such as deer, tapirs, elephants, jaguars and bush pigs, forage among the fallen leaves or prey on each other or smaller animals.

Rainforests are being cut down at an alarming rate for two main reasons. Both large commercial farming companies and individual families clear the forest to gain land to cultivate and graze animals, although the rainforest soil is not suitable for this use. Secondly, forests have been felled to supply tropical hardwoods for furniture-making and building. Woods such as mahogany have been highly prized in wealthy countries for hundreds of years.

More than half of Earth’s rain forests have already been lost due to the human demand for wood and arable land. Rain forests that once grew over 14 percent of the land on Earth now cover only about 6 percent. And if current deforestation rates continue, these critical habitats could disappear from the planet completely within the next hundred years.

The reasons for plundering rain forests are mainly economic. Wealthy nations drive demand for tropical timber, and cash-strapped governments often grant logging concessions at a fraction of the land’s true value. “Homesteader” policies also encourage citizens to clear-cut forests for farms. Sustainable logging and harvesting rather than clear-cutting are among the strategies key to halting rain forest loss.

• Logging interests cut down rain forest trees for timber used in flooring, furniture, and other items.
• Power plants and other industries cut and burn trees to generate electricity.
• The paper industry turns huge tracts of rain forest trees into pulp.
• The cattle industry uses slash-and-burn techniques to clear ranch land.
• Agricultural interests, particularly the soy industry, clear forests for cropland.
• Subsistence farmers’ slash-and-burn rain forest for firewood and to make room for crops and grazing lands.
• Mining operations clear forest to build roads and dig mines.
• Governments and industry clear-cut forests to make way for service and transit roads.
• Hydroelectric projects flood acres of rain forest.

Rainforests in different parts of the world often have similar species, but because they have developed separately for thousands of years, they each have their own characteristics. Both South American jaguars and African leopards have spotted skins that camouflage them in the dappled light of the forest floor. Like leopards, jaguars have rings of black spots on their coats, but they also have smaller spots within those rings.

Body structure: The jaguar is stockier and more muscular than the leopard, with a compact body, a broader head and powerful jaws.  The jaguar’s tail is also generally shorter than the leopard’s tail.

Fur pattern: Though jaguars and leopards both have coats that feature rosette patterns, a jaguar’s rosettes have spots inside them. Both jaguars and leopards can have either golden colored fur or appear black, which is called melanistic.

Body size: The leopard is considered the smallest of the four “big cats.” The other three are the tiger, lion, and jaguar.

Behavior: Jaguars and leopards can both swim very well.  Though jaguars love to spend time in the water, leopards will avoid it.

Jaguars are braver than leopards when it comes to facing off with another species that’s bigger.  Leopards tend to shy away at the sight of a bigger animal like a lion or hyena while jaguars will boldly stand their ground or even attack anaconda or large caimans in their native habitats.

Habitat range: In the wild, jaguars and leopards inhabit totally different continents. The jaguar once roamed from Argentina in South America all the way up to the Grand Canyon in Arizona.  Today, jaguars have been almost completely eliminated from the US and are endangered throughout their range, stretching down to Patagonia in South America.

On the other hand, leopards are found throughout most of Africa and Asia, from the Middle East to the Soviet Union, Korea, China, India, and Malaysia.

Strictly speaking, tropical rainforests should fall within the tropics — between the Tropic of Capricorn and the Tropic of Cancer. In fact, most are found even nearer to the equator. South America, Africa and Asia have large areas of rainforest.

CENTRAL AMERICA

This region was once entirely covered with rainforest, but large areas have been cleared for cattle ranching and for sugar cane plantations. Like other major rainforests, the jungles and mangrove swamps of Central America contain many plants and animals found nowhere else.  Central America is famous for its large number of tropical birds, including many kinds of parrots.

THE AMAZON

The Amazon jungle is the world’s largest tropical rainforest.  The forest covers the basin of the Amazon, the world’s second longest river. The Amazon is home to the greatest variety of plants and animals on Earth.  A 1/5 of all the world’s plants and birds and about 1/10 of all mammal species are found there.

AFRICA

Central Africa holds the world’s second largest rainforest.  To the south east, the large island of Madagascar was once intensively forested, but now much of it is gone. Africa contains areas of high cloud forest, mangrove swamps and flooded forests.  The island of Madagascar is home to many unique plants and animals not found anywhere else.

SOUTHERN ASIA

The rainforests of Asia stretch from India and Burma in the west to Malaysia and the islands of Java and Borneo in the east.  Bangladesh has the largest area of mangrove forests in the world. In Southeast Asia the climate is hot and humid all year round. In the mainland Asia it has a subtropical climate with torrential monsoon rains followed by a drier period.

AUSTRALASIA

Millions of years ago, Australia, New Zealand and the island of New Guinea formed part of a great forested southern continent, isolated from the rest of the world.   Today these countries contain many different species of animal that occur nowhere else. Undergrowth in Australia’s tropical forests is dense and lush.  The forests lie in the path of wet winds blowing in from the Pacific.