A wallaby is a small or middle-sized macropod native to Australia and New Guinea, with introduced populations in New Zealand,[1] Hawaii, the United Kingdom and other countries. They belong to the same taxonomic family as kangaroos and sometimes the same genus, but kangaroos are specifically categorised into the four largest species of the family. The term "wallaby" is an informal designation generally used for any macropod that is smaller than a kangaroo or a wallaroo that has not been designated otherwise.[2]
There are nine species (eight extant and one extinct) of the brush wallaby (genus Notamacropus). Their head and body length is 45to and the tail is 33to long. The 19 known species of rock-wallabies (genus Petrogale) live among rocks, usually near water; two species in this genus are endangered. The two living species of hare-wallabies (genus Lagorchestes; two other species in this genus are extinct) are small animals that have the movements and some of the habits of hares. The three species (two extant and one extinct) of nail-tail wallabies (genus Onychogalea) have one notable feature: a horny spur at the tip of the tail; its function is unknown. The seven species of pademelons or scrub wallabies (genus Thylogale) of New Guinea, the Bismarck Archipelago, and Tasmania are small and stocky, with short hind limbs and pointed noses. The swamp wallaby (genus Wallabia) is the only species in its genus.Another wallaby that is monotypic is the quokka or short-tailed scrub wallaby (genus Setonix); this species is now restricted to two offshore islands of Western Australia which are free of introduced predators. The seven species of dorcopsises or forest wallabies (genera Dorcopsis (four species, with a fifth as yet undescribed) and Dorcopsulus (two species)) are all native to the island of New Guinea.
One of the brush wallaby species, the dwarf wallaby (Notamacropus dorcopsulus), also native to New Guinea, is the smallest known wallaby species and one of the smallest known macropods. Its length is about 46cm (18inches) from the nose to the end of the tail, and it weighs about 1.6kg (03.5lb).[3]
Wallabies are hunted for meat and fur.
The name wallaby comes from Dharug walabi or waliba.[4] Another early name for the wallaby, in use from at least 1802, was the brush-kangaroo.[5]
Young wallabies are referred to as "joeys", like many other marsupials. Adult male wallabies are referred to as "bucks", "boomers", or "jacks". Adult female wallabies are referred to as "does", "flyers", or "jills". A group of wallabies is called a "mob", "court", or "troupe". Scrub-dwelling and forest-dwelling wallabies are known as "pademelons" (genus Thylogale) and "dorcopsises" (genera Dorcopsis and Dorcopsulus), respectively.
Although members of most wallaby species are small some can grow up to approximately two metres in length (from the head to the end of the tail). Their powerful hind legs are not only used for bounding at high speeds and jumping great heights, but also to administer vigorous kicks to fend off potential predators. The tammar wallaby (Notamacropus eugenii) has elastic storage in the ankle extensor tendons, without which the animal's metabolic rate might be 30–50% greater.[6] It has also been found that the design of spring-like tendon energy savings and economical muscle force generation is key for the two distal muscle–tendon units of the tammar wallaby (Macropus-Eugenii).[7] Wallabies also have a powerful tail that is used mostly for balance and support.
Wallabies are herbivores whose diet consists of a wide range of grasses, vegetables, leaves and other foliage. Due to recent urbanization many wallabies now feed in rural and urban areas. Wallabies cover vast distances for food and water, which is often scarce in their environment. Mobs of wallabies often congregate around the same water hole during the dry season.
Wallabies face several threats. Dingoes, domestic and feral dogs, feral cats, and red foxes are among their predators. Humans also pose a significant threat to wallabies due to increased interaction (wallabies can defend themselves with hard kicks and biting). Many wallabies have been involved in vehicular accidents, as they often feed near roads and urban areas.
Wallabies are not a distinct genetic group. Nevertheless, they fall into several broad categories. Brush wallabies of the genus Notamacropus, like the agile wallaby (Notamacropus agilis) and the red-necked wallaby (Notamacropus rufogriseus), are most closely related to the kangaroos and wallaroos and, aside from their size, look very similar. These are the ones most frequently seen, particularly in the southern states.
Rock-wallabies (genus Petrogale), rather like the goats of the Northern Hemisphere, specialise in rugged terrain and have modified feet adapted to grip rock with skin friction rather than dig into soil with large claws. There are at least 19 species and the relationship between several of them is still poorly understood. Several species are endangered. Captive rock-wallaby breeding programs, like the one at Healesville Sanctuary, have had some success and a small number have recently been released into the wild.
The banded hare-wallaby (Lagostrophus fasciatus) is thought to be the last remaining member of the once numerous subfamily Sthenurinae, and although once common across southern Australia, it is now restricted to two islands off the Western Australian coast which are free of introduced predators. It is not as closely related to the other hare-wallabies (genus Lagorchestes) as the hare-wallabies are to the other wallabies.
New Guinea, which was, until fairly recent geological times, part of mainland Australia,[8] has at least five species of wallabies.
Wallabies are widely distributed across Australia, particularly in more remote, heavily timbered, or rugged areas, less so on the great semi-arid plains that are better suited to the larger, leaner, and more fleet-footed kangaroos. They also can be found on the island of New Guinea.[9]
Wallabies of several species have been introduced to other parts of the world, and there are a number of successfully breeding introduced populations, including:
The term "wallaby" is not well defined and can mean any macropod of moderate or small size. Therefore, the listing below is arbitrary and taken from the complete list of macropods.
Genus Notamacropus
Genus Wallabia
Genus Petrogale
Genus Lagostrophus
Genus Lagorchestes
Genus Onychogalea
Genus Dorcopsis
Genus Dorcopsulus
Genus Thylogale
Genus Setonix