Macropus dorsalis (black-striped wallaby) is a marsupial that makes its home in Australia. Historically, M. dorsalis was widespread throughout New South Wales and Queensland. Due to the destruction of their habitat, the current range for M. dorsalis is now confined to a small part of northern New South Wales and areas of Queensland. (Hoolihan and Goldizen, 1998)
Macropus dorsalis prefers warm, wet summers and dry winters. These wallabies can usually be found in dense areas of vegetation. These areas include dense rainforests, forests with a substantial under story, and areas of regrown brigalow scrub, which provide shelter during the day. Many times, they will be found on the edge of these dense vegetation areas, where they can migrate out into the pastures at night to feed. (Evans and Jarman, 1999)
Macropus dorsalis gets its common name, black-striped wallaby, from the black stripe that runs along the middle of its back. The head and body stand from 100 cm to 159 cm in height, with the tail being 54 to 83 cm in length. Like other members of the Macropodidae, the length of the tail is an adaptation that allows them to balance both when moving and sitting still. The hind legs also tend to be larger and stronger than the front legs, allowing these animals to use a jumping motion for movement. Adult males tend to be three times larger than adult females. (Feldhamer, et al., 1999; "Guide To Caring For Australian Animals", 2002)
Details on the mating habits of M. dorsalis are not available in the literature. However, other species in the genus Macropus are polygynous. Males compete for access to females. This competition can become very intense, with injuries occuring to the competitors in the interaction. There have been accounts of females also being injured when males are overly aggressive in pursuing them. Generally, the dominant male in a social group will be the one to mate with the females. Because of the extreme sexual dimorphism in M. dorsalis, it is likely that the mating system of this species is similar. (Hand, 1989)
The general reproductive behavior of the genus Macropus is interesting in several respects. Like all members of the order Diprododontia, these animals lack a placenta, and so are unable to efficiently provide nutrients and oxygen to a large fetus. They therefore give birth to very altricial young, which are then nursed in a pouch, where they complete their development. (Nowak, 1999)
Females in Macropus are reported to be polyestrus. The estrus cycle of most members of the genus is between 28 and 45 days in length. Females may be receptive to males only for a breif time during this cycle. Females of species which have been studied undergo a postpartum estrus, within two days of parturition, and typically conceive at that time. (Nowak, 1999)
The breeding season of this species has not been reported. In captivity, births of M. dorsalis have been recorded as occuring in March, September, and October. When a female is not nursing a joey, gestation is short in the genus, ranging from 33 to 35 days. However, the embryo undergoes a diapause if the mother is nursing another offspring when conception occurs. Embryonic dispause happens after the egg is fertilized and the embryo begins to develop, but the development is arrested at around the 70 to 100 cell stage. Because of the short gestation and the need for an empty pouch in which to nurse and incubate a newborn joey, this diapause is highly adaptive. After the first joey leaves the mother's pouch for good, then the embryo in the mother resumes the process of development. Because of embryonic diapause, a mother can rapidly produce a new offspring, should her first joey fail to survive the harsh Australian environment. (Feldhamer, et al., 1999; Hand, 1989; "Guide To Caring For Australian Animals", 2002; Nowak, 1999)
Although details are not available for M. dorsalis, other members of the genus weigh less than one gram at birth (Macropus rufus weighs 0.75 g). and it is likely that M. dorsalis neonates are comparably small. The newborn makes its way by squirming from the birth canal to the opening of the pouch, which it enters. Once in the pouch, the young attaches to a nipple. In M. rufus, the young does not let go of the nipple until it is 70 days old, and does not stick its head out of the pouch until it is 150 days old. It may begin to leave the pouch for short intervals by the age of 190 days, and may permanently leave the pouch by about 235 days of age. Within Macropus development seems to take about the same amount of time, despite differences in final adult size, so it is likely that these events are similarly timed in M. dorsalis. Weaning occurs in M. dorsalis between 10 and 12 months of age, and the young become more or less independent at that time. The average age of independence is reported to be 300 days of age. (Feldhamer, et al., 1999; Hand, 1989; "Guide To Caring For Australian Animals", 2002; Nowak, 1999)
Males are sexually mature at the age of 20 months, whereas females are sexually mature as young as 14 months. (Feldhamer, et al., 1999; Hand, 1989; "Guide To Caring For Australian Animals", 2002)
Parentla investment in this species has not been documented. However, in Macropus, a great deal is known. After the gestation period, the joey soon finds its way into the mother's pouch where it begins the development process. The mother feeds the joey with her milk while the joey is still confined to the mother's pouch. After 5 to 6 months the joey may begin to leave the pouch for short periods of time, always returning to the mothers pouch. A joey will then begin to spend 1-2 hours a day out of the mother's pouch, and begin feeding on grass four times a day at the age of around 7 months. The joey becomes increasingly independent and spends more time out of the pouch, relies less on the mother for milk, and finally becomes independent by about a year of age. Males have no role in parental care. ("Guide To Caring For Australian Animals", 2002; Nowak, 1999)
The lifespan of M. dorsalis has not been reported, but information on the genus Macropus reveals that they can live to be 20 years of age in captivity, but may only survive to be 10 years of age in the wild. It is likely that this species is similar to other members of the genus. ("Western Grey Roos", 2002; Nowak, 1999)
Black-striped wallabies generally live in groups of from 2 to 20 animals. Most of the feeding is done in groups. Animals typically remain within 30 meters of each other during feeding times. This closeness allows for communication in the dense vegetation, where sounds would be hard to hear from a distance farther than 30 meters. Black-striped wallabies stay withing closer proximity of other group members than do other macropods, which live in open areas and do not have vegetation to block the sound. (Hoolihan and Goldizen, 1998)
Macropus dorsalis has open-membership groups. This means that group membership changes over time, and individuals do not always maintain the same associations. Groups size also varies over time. (Hoolihan and Goldizen, 1998)
Macropus dorsalis sleeps during the day and feeds during the night, making them primarily nocturnal.
Locomotion in macropods is unique among mammals. When moving rapidly, these animals hop using only their hind legs, keeping their tails extended behind them for balance. However, when moving slowly, macropods use all four feet and their tails in locomotion. (Nowak, 1999)
Young joeys are known to box playfully, but the same behavior in adult males is serious business. Adult males box to determine who dominance ranking within the group. Dominance rank influences mating prospects. (Hoolihan and Goldizen, 1998; Nowak, 1999)
The size of the home range in this species has not been reported.
Information on communication in this species is scant. M. dorsalis uses vocal communication to maintain contact between individuals when groups are in thick underbrush. Some members of the genus Macropus will growl to alarm predators. (Hoolihan and Goldizen, 1998; "Western Grey Roos", 2002)
Other forms of communication also play some role in this species. Tactile communication is used in the boxing play of young joeys, as well as in the sparring of adults. It probably also occurs during mating, and it definitely happens between a mother wallaby and her joey. Visual signals such as body postures are probably also important in aggressive encounters, although because of the dense vegetation in the habitat of this species, it can be assumed that visual signals are not used over long distances. (Hoolihan and Goldizen, 1998)
Black-striped wallabies feed mainly on monocot grasses, but also browse on forbs and other shrubs. They have the ability to change diet to eat more shrubs when there is less grass available in the winter. They prefer the soft, leafy part of the plant. M. dorsalis generally feeds during the night in either pastures or open fields. (Baxter, et al., 2001)
Humans are one of the main predators of M. dorsalis. Ranchers receive permits to hunt them on their land. The goal of the ranchers is to elimate M. dorsalis from their land, beause these wallabies damage crops and pastures. It is also likely that dingos prey upon this species. (Baxter, et al., 2001)
Macropus dorsalis is an important disperser of seeds. Seeds of monocots upon which M. dorsalis feeds have a higher chance of germination if they have gone through the digestive system of M. dorsalis. Wallabies also help replenish nutrients to the area through their feces. To the extent that this species serves as prey, they affect predator populations. (Jarman, 1994)
Macropus dorsalis has not been reported to have any particular positive impact on human economies. However, the genus Macropus is an important animal in zoos across the world. Also, there may be some ecotourism related to these animals, as foreign visitors to Australia like to see macropods in their natural habitat. ("Western Grey Roos", 2002)
Macropus dorsalis is considered to be a pest. Ranchers have long believed that M. dorsalis has caused the depletion of grass in their pastures. Even though studies have shown that cattle are the main cause of the depletion of grasses in the pastures, the Queensland Parks and Wildlife Service allows ranchers to hunt wallabies on their land. Ranchers have also cleared areas of brush, destroying areas for the wallabies to take shelter during the day. (Baxter, et al., 2001)
The loss of M. dorsalis has been of some concern in Australia. Much of the land that used to be covered in dense forest has now been cleared for agricultural fields and pastures. This has caused a decline in both the range and population size of M. dorsalis. Management is the key to the survival of black-striped wallabies. Dense forested areas need to be maintained and restored to ensure their survival. Also, allowing the ranchers to hunt them during the dry season when grass is not as abundant would have a smaller impact on the populations than the current hunting regime. (Hoolihan and Goldizen, 1998)
Macropus dorsalis is a species that has been studied very little, and more biological studies need to be done on the species to get a better understanding of how these animals fit into the ecosystem. This would allow biologists to better manage the population of back-striped wallabies in the future. (Baxter, et al., 2001)
Nancy Shefferly (editor), Animal Diversity Web.
Todd Jewell (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor, instructor), University of Wisconsin-Stevens Point.
Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.
uses sound to communicate
living in landscapes dominated by human agriculture.
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
uses smells or other chemicals to communicate
ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates
humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.
At about the time a female gives birth (e.g. in most kangaroo species), she also becomes receptive and mates. Embryos produced at this mating develop only as far as a hollow ball of cells (the blastocyst) and then become quiescent, entering a state of suspended animation or embryonic diapause. The hormonal signal (prolactin) which blocks further development of the blastocyst is produced in response to the sucking stimulus from the young in the pouch. When sucking decreases as the young begins to eat other food and to leave the pouch, or if the young is lost from the pouch, the quiescent blastocyst resumes development, the embryo is born, and the cycle begins again. (Macdonald 1984)
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
union of egg and spermatozoan
an animal that mainly eats leaves.
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
An animal that eats mainly plants or parts of plants.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
having more than one female as a mate at one time
rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.
specialized for leaping or bounding locomotion; jumps or hops.
scrub forests develop in areas that experience dry seasons.
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
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Evans, M., P. Jarman. 1999. Diets and feeding selectivities of bridled nailtail wallabies and black-striped wallabies. Wildlife Research, 26: 1-19.
Feldhamer, G., L. Drickamer, S. Vessey, J. Merritt. 1999. Mammalogy: Adaptatation, Diversity, and Ecology. USA: McGraw Hill.
Hand, S. 1989. Care and Handling of Australian Native Animals. Australia: Surrey Beatty & Sons Pty Limited.
Hoolihan, D., A. Goldizen. 1998. The grouping dynamics of the black-striped wallaby. Wildlife Research, 25: 467-473.
Jarman, P. 1994. The eating of seedheads by species of Macropodidae. Australian Mammalogy, 17: 51-63.
Nowak, R. 1999. Walker's Mammals of the World, Sixth Edition. Baltimore and London: The Johns Hopkins University Press.