WALLABY: CHARACTERISTICS, CLASSIFICATION, HABITAT, SPECIES, BEHAVIOR - BIOLOGY - 2025

The wallaby or wallaby is the common name for any species of diprotodont marsupial, a member of the Macropodidae family, whose size is smaller than that of kangaroos. The size can vary from 46 centimeters to 1.8 meters.

At present, there are about 30 species, distributed mainly in Australia and the islands of New Guinea. In these regions it lives in mountains, jungles or rocky areas.

Wallaby. Source: pixabay.com

Its hind limbs are powerful, while the front limbs are shorter, but with just as strong musculature as the hind limbs. The wallaby has an elongated and small head, compared to the body.

As for the eyes, they are large and are located on the sides of the head. The muzzle is elongated, ending in a small mouth, whose upper lip is divided.

characteristics

- Size

The dimensions of the wallaby are smaller than those of the kangaroo. Depending on the species, it can be medium or small in size. In general, the largest ones can measure 1.8 meters, with a weight of 42 kilograms.

As for the smallest member of this group, it is the dwarf wallaby. Its body has a length of 46 centimeters and a body mass of approximately 1.6 kilograms.

- Extremities

The hind limbs are powerful and narrow, much more compact than that of kangaroos. This particularity allows it to move agilely in the wooded areas where it lives. In addition, when the wallaby fights, it can provide strong kicks with its hind legs. These have four fingers, two of which are vestigial.

Also, they have large elastic tendons. In these, the energy of elastic tension, used in the jumps, is stored. On the other hand, rebound occurs due to the spring action of the tendons, instead of being the product of muscular effort.

In relation to the forelimbs, they are short and have five fingers, including a non-opposable thumb. Each of these ends in a sharp claw. These legs are made up of a large group of muscles, which in males are particularly strong.

This is because they are used in fights and in demonstrations of dominance before the group. In addition, the wallaby uses its front legs to jump long distances and to jump, while moving at great speed.

- Tail

The tail is long and has a thick base. Likewise, it is muscular, which contributes to the maintenance of body balance, just as it intervenes when the animal moves in a pentapedal manner. Also, it supports the body while resting.

- Fur

The hair is soft, woolly and short. With regard to coloration, it varies according to the genus and the species. However, it is generally bright and each wallaby can present two or three different shades.

Coat colors include gray, light brown, brownish-brown, and reddish. alternated with white hairs that give it a gray appearance. Some may have stripes on the head, hind legs, or back.

An example of this diversity of colors is the red-necked wallaby (M. rufogriseus), which has reddish shoulders and back of the neck, while the flanged wallaby (Onychogalea fraenata) has stripes on the shoulders.

Also, the pretty-faced wallaby (M. elegans) has cheek markings and the rock wallaby (Petrogale lateralis) has a body in shades of gray and brown, with stripes and patches.

- Teething

The wallaby lives in dense forests, where it mainly feeds on leaves. Due to the characteristics of the vegetables you eat, you need flat teeth, which help grind food. Thus, their teeth are not sharp, so the crowns of the molars are less pronounced.

However, this mammal has a sharp mouthpiece, located in the upper jaw. This is used to cut the plants, when this is necessary. Also, unlike kangaroos, the wallaby maintains its premolars.

- Marsupio

The pouch is a fold of skin that covers the female's breasts, forming an epidermal pouch. In this, the breeding culminates its development. This structure is in the ventral position, opening horizontally in the frontal area.

The bursa is made up of powerful and flexible ligaments and muscles. This allows it to adjust to the size that the baby acquires as it develops. On the other hand, the mother can contract said muscles, to close the pouch and thus keep the youngster safe.

Another peculiarity of the pouch is that it is covered with sweat glands, which secrete antimicrobial substances. This has the function of protecting the embryo from bacteria, parasites and viruses. Also, on the inside, it lacks hairs, so direct contact with the skin keeps the young person in a warm environment.

Features

The baby is born when it is still an embryo. At that time, it only has developed the forelimbs, which it uses to move from the mother's uterus to the marsupium. In the bag, the embryo attaches itself to one of the breasts, where it obtains a highly nutritious milk rich in antibodies.

The composition of this milk varies, to satisfy the requirements of the young, as it is developing. This remains in the pouch for about eight months, although it can come regularly for six more months.

In this sense, although the wallaby is fully developed, the mother carries it in the bag to defend it from the threat of predators.

- Locomotion

The wallaby has a muscular system designed to keep moving by jumping, without incurring an exaggerated expenditure of energy.

In addition to this powerful limb musculature, this group of macropods has a set of tendons that connect the tail with the hip bones. This unique combination of muscles and tendons allows the wallaby to move efficiently.

Likewise, it has caudal vertebrae that are adapted for lateral movements, which are part of the locomotor repertoire.

Regarding the jump, both hind legs are propelled at the same time from the ground, being able to do it at different speeds, depending on their need. Likewise, it is capable of maintaining a constant speed for a long time.

On the other hand, when traveling at low speed, it does so using penta-pedal locomotion. In this movement, it uses the tail, with which, together with the front legs, it forms a tripod. As this occurs, the hind limbs are brought forward.

In the pentapedal movement, the role of the tail is fundamental, since its propulsion force is greater than that exerted by the front and rear legs.

Classification and species

The wallaby belongs to the same family as kangaroos and often the same genus. However, the term is an informal designation used to designate macropods that are smaller than kangaroos. The classification would be as follows:

Genus: Macropus

Species:

Genus: Lagostrophus

Species:

Genus: Dorcopsis

Species:

Genus: Onychogalea

Species:

Genus: Thylogale

Species:

Genus: Dorcopsulus

Species: Dorcopsulus macleayi.

Genus: Wallabia

Species: Wallabia bicolor.

Habitat and distribution

Distribution

The wallaby is widely distributed throughout Australia, although it is also found on the island of New Guinea. However, it has been introduced in various regions worldwide.

Thus, in New Zealand it is located on the island of Kawau, in the area around Lake Tarawera and in South Canterbury. It also lives on the Isle of Man, between England and Ireland. In that island territory it lives mainly in the Ballaugh Curraghs wetlands.

In Hawaii there is a small exotic population, in the Kalihi Valley area, on the island of Oahu. In addition, it is found in Peak (England), on the island of Inchconnachan (Loch Lomond-Scotland) and on the island Lambay, on the east coast of Ireland.

Relative to the United Kingdom, it was introduced in Devon, Teignmouth, Devon, East Sussex, Ashdown Forest and the islands of Bute and Lundy. In France, the wallaby is found in the southern area of ​​the Rambouillet forest, west of Paris.

Habitat

These species inhabit very varied areas, including mountains, savannas, rocky areas, or jungles. Thus, its preferred regions are the rugged or wooded, rather than the open arid plains. As for the smaller wallabies, they prefer forests.

Each species lives in a specific area, where it has the right conditions to develop. For example, the red-necked wallaby (M. rufogriseus), inhabits the scrublands of southeastern Tasmania and Australia.

The whip-tailed wallaby (M. parryi) is found in the coastal open forests of eastern Australia. Likewise, quokka or short-tailed scrub wallaby (Setonix brachyurus) is restricted to the islands of Western Australia, especially Rottnest Island and Bald Island.

State of conservation

Wallabies are grouped into several genera, which include numerous species. A large part of these populations decrease day by day, which causes them to be in danger of extinction.

Some have already disappeared from their natural habitat, such as the Grey's wallaby (Macropus greyi), the eastern wallaby (Lagorchestes leporides) and the claw-tailed wallaby (Onychogalea lunata).

Another important group is threatened. The IUCN has included several species in its red list, among which are the Proserpine rock wallaby (Petrogale persephone), the rock wallaby (Petrogale inornata) and the red-necked wallaby (Macropus rufogriseus).

Also, there are the yellow-legged rock wallaby (Petrogale xanthopus), the Mareeba wallaby (Petrogale mareeba), and the swamp wallaby (Wallabia bicolor).

Threats

The wallaby is threatened by multiple factors, one of the main ones being the loss and fragmentation of its natural habitat. This situation has the consequence that populations are forced to live near urbanized areas.

Because of this, the mammal can die from collision with vehicles on the roads and from the predation of foxes and dogs. Also, in some regions, the wallaby is considered a pest of crops, which is why it is hunted by the locals.

Another fact that affects these populations is competition with other domestic herbivorous animals and with introduced species, such as sheep, rabbits and goats. In addition, species such as the yellow-legged wallabies have been hunted for their skins and to market their meat.

Feeding

This macropod is herbivorous and its diet is based on a wide variety of plants, among which are shrubs, grasses, mosses and fungi. Also, eat grasses, shrubs, hay, tree bark, fruits, and vegetables.

On the other hand, you can go long periods of time without drinking water. A factor that contributes to meeting your need for water is the intake of plants, which are high in liquid. Even several species, such as the Tammar wallaby, can drink seawater.

Digestive process

Once the animal takes the food, it uses its lips and tongue to push it towards the molars. They chew food, using their flat structure and the side-to-side movement of the jaw.

In addition, there are three important muscles, the masseter, temporal and pterygoid, which are attached to the jaw and temple. These contribute to the biting and chewing process of vegetables.

The wallaby's digestive system is characterized by having a large salivary gland. It produces high levels of saliva, which contains a high concentration of bicarbonate and sodium ions. In addition, this mammal can regurgitate part of the ingested vegetables, thus contributing to the degradation of cellulose.

Stomach

In relation to the stomach, it is divided into two cavities: the anterior and the posterior. The front chamber is shaped like a sac and contains abundant bacteria. It is in the tubiform and sacciform areas of this area that bacterial fermentation occurs.

In this way, the breakdown of cell wall elements, such as lignin, cellulose and hemicellulose, begins.

On the other hand, the posterior stomach is the smallest part of this organ. This is where acid digestion mainly takes place. Thus, this part of the stomach receives the pre-digested mass, on which acids and enzymes act.

The organic compounds obtained from the degradation of food are used to obtain the necessary energy in the different organic processes.

www.youtube.com/watch?v=uKi0pXhQitE

Reproduction

Sexual maturity in males occurs around two years, while the female can reproduce when she is between 14 and 19 months. As for the mating season, it can be at any time of the year. However, unions are more frequent during the summer, from December to February.

Males can fight with others, for the right to copulate with females. In relation to the reproductive process, it begins when the ovum is fertilized by the sperm. Once fertilized, it becomes embedded in the wall of the uterus.

In the particular case of the wallaby, the placenta does not originate. The egg feeds on the yolk that surrounds it. Once it is completely consumed, the embryo is born. This occurs around day 28, counting from fertilization.

Development of the embryo

The embryo emerges from the mother's body through an opening called the cloaca. It moves using its forelimbs, traveling through the mother's fur, until it reaches the pouch.

Once inside, the embryo goes to the nipples. Because the muscles that allow him to suck milk are not developed, the nipple swells inside his mouth. Subsequently, the jaw develops and the young can unhook and suck voluntarily.

After four or five months, the young man comes out of the bag. However, he returns to this if he feels threatened.

A few days after giving birth, the female goes into heat again and reproduces. This new fertilized egg can enter a stage of inactivity, called embryonic diapause. Its development is activated again when the previous calf leaves the pouch.

Behavior

The wallaby is usually an active animal at night and at dawn, but these patterns could vary by species. Smaller species are generally solitary, while larger ones can form groups.

During the summer, this mammal tends to congregate around a body of water. In the hours where the heat is extreme, it remains in its resting place, going out to look for its food when the ambient temperature drops.

It is not usually an aggressive animal, but if it feels in danger, it can kick the predator. For this it uses its powerful hind legs.

In the event of perceiving a threat, the wallaby alerts its conspecifics, striking the ground hard with its hind legs. In addition, he can fight, using his forelimbs, making movements similar to boxing.

To communicate, he may cough, growl or whistle. When the mother needs to call her calf, she can make a snap.

References

1. Sara Reardon (2017). Wallaby milk acts as a placenta for babies. Gene-expression analysis suggests that marsupial placentas take two different forms. Recovered from nature.com.
2. Jennifer Horton (2019). What's the difference between a wallaby and a kangaroo ?. Recovered from animals.howstuffworks.com.
3. Encycloapedia Britannica (2019). Wallaby. Recovered from Britannica.com
4. Dawson, R. (2015). Morphological correlates of pentapedal locomotion in kangaroos and wallabies (Family: Macropodidae). Recovered from research-repository.uwa.edu.au.
5. Baudinette RV, Snyder GK, Frappell PB. (1992). Energetic cost of locomotion in the tammar wallaby. Recovered from ncbi.nlm.nih.gov.
6. Wikipedia (2019). Wallaby. Recovered from en.wikipedia.org.