Wallaby


 * Prehistoric Animal (Giant Short-Faced Kangaroo) Future Animal (Wallion)**

The **Red-necked Wallaby**, or //**Macropus rufogriseus**//, is the most common species of wallaby in the world. The species is widespread in the temperate areas of south-eastern Australia and in most of Tasmania, where it is commonly known as the **Bennett’s Wallaby**. The Red-necked Wallaby is a marsupial belonging to the family Macropodidae, which also includes kangaroos, pandemelons and tree-kangaroos.

The name //wallaby// originated from a native name given to the animals by the Eora Aboriginal tribe in New South Wales. The term wallaby is used as an informal designation to classify any macropod smaller than a kangaroo or wallaroo. As a result, any complete lists of wallaby species are arbitrary, although most lists put the number of wallaby species as around 30.

The following report describes both the habitat of the Red-necked Wallaby, and five different structural, behavioural and physiological adaptations that this animal has evolved in order to thrive in its environment. = Scientific Classification =


 * ** Level ** || ** Classification ** ||
 * Kingdom || Animalia ||
 * Phylum || Chordata ||
 * Class || Mammalia ||
 * Infraclass || Marsupialia ||
 * Order || Diprotodontia ||
 * Family || Macropodidae ||
 * Genus || Macropus ||
 * Species || M. rufogriseus ||

= Habitat =

Red-necked Wallabies are perfectly adapted to the unique Australian environment. The species requires a particular combination of environmental factors to develop, mate and reproduce. Red-necked Wallabies predominantly live in heavily timbered areas of open forest near the Australian coastline. Their geographical range stretches from Rockhampton in Queensland to the eastern border of South Australia on the Australian mainland. (See map 1) Red-necked Wallabies also live in Tasmania and on many of the Bass Strait Islands, although it remains unclear whether some of the islands have native wallaby populations or introduced ones.
 * Geographical Range**

Like most other wallabies, red-necked wallabies thrive in rugged sclerophyll forests. They are much less common on the great semi-arid plains further inland, which are better suited to kangaroos - the leaner, taller and more fleet-footed relatives of the wallaby. Sclerophyll forests are characterised by plants (normally wattles, eucalypts and banksias) with short, hard and often spiky leaves. The word “sclerophyll” comes from the Greek words //sclero// (stiff) and //phyllon// (leaf). Although Red-necked Wallabies prefer to live in areas of dense vegetation (due to the rich sources of food and shelter), they have a versatile habitat compared to other species of wallaby. Tasmanian Red-necked Wallabies, or Bennett’s Wallabies live on the mountains of Tasmania.
 * Vegetation**

Due to its relatively large size, the Red-necked Wallaby has few natural predators to fear in its environment. The few predators that do hunt wallabies include canines such as dingoes and foxes as well as large reptiles such as snakes and crocodiles. Red-necked wallabies are herbivores. Their diet consists mainly of grasses and herbs on the forest floor.
 * Predators**

In terms of climate, the habitat of Red-necked Wallabies is generally temperate, although the northern part of its geographic range along the coast of Queensland is subtropical with warm, humid summers and mild winters, and the climate of Tasmania is much cooler, with four distinct seasons.
 * Climate**

The natural habitat of other species of wallaby varies greatly depending on the group that the species belongs to. The main groups are rock, swamp, brush, forest and shrub wallabies. Rock wallabies in particular live in the southern deserts of Australia, near loose piles of large boulders, vertical rock cliffs with caves and mid-level ledges and isolated rock stacks. Swamp wallabies, as their name suggests, live in swamps along the east coast of Queensland. They inhabit thick undergrowth in woodlands and forests.
 * Other Species of Wallaby**

= = = Adaptations and Environmental Pressures =

One of the most obvious and practical physical adaptations of the Red-necked Wallaby are its large, muscular hind legs and oversized feet. In fact, //Macropodidae,// the family that wallabies and kangaroos belong to, is Greek for “big foot”. All wallabies (and kangaroos) have the unique ability to store elastic potential energy in their tendons within their hind legs. This allows wallabies to propel themselves by using the spring action of their tendons as opposed to using muscular effort. This saves valuable energy when the wallaby is travelling across the Australian bush.
 * Adaptation 1 (Structural):**

As a result of this adaptation, wallabies have the ability to travel swiftly across the forest floor while exerting very little effort. This not only allows them to escape from predators such as the dingo or the fox, but also enables wallabies to locate food much quicker than most other Australian animals, as the wallaby’s legs are built for agility in densely forested areas.

One possible environmental pressure that could have stimulated the gradual development of big, strong hind legs in wallabies is the sheer vastness of the Australian continent combined with the generally low fertility of Australian land. These two factors mean that the distance between two food sources for the wallaby may be very far. Wallabies developed their large legs and efficient method of travelling to allow them to reach food faster. This increases the chance of survival. The strong hind legs would have also allowed wallabies to increase their chances of escaping from predators.

Another structural adaptation of the Red-necked Wallaby is its long muscular tail. The tail of the wallaby serves as a steadying “rudder” when leaping, and can function as a third leg when the wallaby is stationary and resting. The tail may also give extra traction to the wallaby as it moves around, providing an extra point of contact between the wallaby and the forest floor.
 * Adaptation 2 (Structural):**

As a result of this adaptation, wallabies rarely, if ever, lose their balance and tip over. Although they are bipedal like humans, wallabies are much steadier than Homo sapiens. They have the ability to travel at high speeds through rough, uneven terrain. This allows wallabies to escape easily from their predators, increasing their chances of survival and reproducing.

The environmental pressure that gave rise to the wallaby’s tail could potentially have been the same as the pressure that stimulated the development of strong hind legs - the sheer vastness of the Australian continent combined with the generally low fertility of Australian land. These two factors mean that the distance between two food sources for the wallaby may be very far. Wallabies developed their strong tails to increase their mobility and allow them to reach food faster. This increases the chance of survival. The strong tail would have also allowed wallabies to increase their chances of escaping from predators.

The Red-necked Wallaby has a natural born instinct to flee at the first sign of danger. In fact, this behavioural adaptation is at time so overwhelming that they have been known to run in front of moving cars and jump off cliffs in extreme cases. Their instinct to flee is triggered by their strong sense of smell and acute hearing. When Red-necked Wallabies hear or smell a potential predator, they instinctively use their strong hind legs to propel themselves through the forest and away from danger.
 * Adaptation 3 (Behavioural):**

As a result of this adaptation, healthy Red-necked Wallabies are rarely ever caught by their predators. Their tendency to flee at the slightest disturbance makes them very difficult prey to locate, and when Red-necked Wallabies do come in contact with predators, their speed and agility usually allows them to escape safely. This increases their chances of survival and reproducing.

The environmental pressure that the instinct to flee at the sign of danger is most likely the constant pressure of being eaten by skilled hunters such as the fox and the dingo, who themselves have evolved a wide range of skills to locate and kill prey. This pressure created a natural selection process where the less alert wallabies perished and the ones that fled at the first sign of danger survived to pass on their genes to the next generation.

Red-necked Wallabies live in Australia, one of the driest and hottest continents on Earth. One way that Red-necked Wallabies keep cool is by licking their paws and wrists. Wallaby skin is thinner on their forearms than on the rest of their body, and the blood vessels are very close to the surface of their skin in those areas. As the saliva from a wallaby’s tongue evaporates it cools the skin down.
 * Adaptation 4 (Structural/Behavioural):**

As a result of this adaptation, Red-necked Wallabies can keep cool during the hot Australian summers, even after travelling many kilometres through forests in search of food. Licking uses much less water than sweating does. As a result Red-necked Wallabies can cool their body down while conserving as much water as they can. This is vital to the survival of the species, as Australia often goes through periods of drought, and the Red-necked Wallaby can go without water for prolonged periods of time. media type="youtube" key="YPFa451HkEw" height="349" width="425" align="right"

The environmental pressure that gave rise to this adaptation has been confirmed to be the hot, arid climate of the Australian continent. This unique climate has forced wallabies to evolve an efficient way of cooling their bodies down while conserving precious water.

One of the most fascinating adaptations of female Red-necked Wallabies (as well as many other mammals) is their ability to temporarily freeze the development of an embryo during pregnancy. This occurs in areas with poor food sources and in times of severe drought. The process is known as embryonic diapause. Mammals use diapause to time the birth of their offspring to meet favourable environmental or metabolic conditions. It is to a female's benefit to have ideal conditions (e.g. mild weather, available food) before giving birth, as reproduction has a high energy cost.
 * Adaptation 5 (Physiological):**

As a result of this adaptation, mother Red-necked Wallabies can dramatically decrease the chances of their offspring dying in infancy by the development of an they sense favourable conditions. This increases the ability of Red-necked Wallabies to produce fertile offspring.

One possible environmental pressure that gave rise to this adaptation is predators, harsh environmental conditions or lack of available food killing off many Red-necked Wallabies during infancy. This threatens the existence of the species as a whole and as a result natural selection encouraged the development of embryonic diapause to increase the chances of Red-necked Wallabies producing fertile offspring.



= Bibliography =

= =
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