By Todd Jewell
Geographic Range
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)
Biogeographic Regions:
australian 
(native ).
Habitat
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)
These animals are found in the following types of habitat:
temperate ; tropical ; terrestrial .
Terrestrial Biomes:
forest ; rainforest ; scrub forest .
Other:
agricultural .
Physical Description
(39.37 to 62.6 in)
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; Noah's Ark Wildlife Coalition and Inc, 2002)
Some key physical features:
endothermic ; bilateral symmetry .
Sexual dimorphism: male larger.
Reproduction
These animals are capable of producing approximately one offspring every year.
Breeding season for this species has not been reported, but births are known to take place in March, September, and October.
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)
Mating systems:
polygynous .
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; Noah's Ark Wildlife Coalition and Inc, 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; Noah's Ark Wildlife Coalition and Inc, 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; Noah's Ark Wildlife Coalition and Inc, 2002)
Key reproductive features:
iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous ; embryonic diapause ; post-partum estrous.
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. (Noah's Ark Wildlife Coalition and Inc, 2002; Nowak, 1999)
Parental investment:
altricial ; pre-fertilization (protecting: female); pre-hatching/birth (provisioning: female, protecting: female); pre-weaning/fledging (provisioning: female, protecting: female); pre-independence (provisioning: female, protecting: female).
Lifespan/Longevity
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. (Kangaroo Conservation Center, 2002; Nowak, 1999)
Behavior
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)
Home Range
The size of the home range in this species has not been reported.
Key behaviors:
terricolous; saltatorial ; nocturnal ; motile ; social ; dominance hierarchies .
Communication and Perception
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; Kangaroo Conservation Center, 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)
Food Habits
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, Moll, and Lisle, 2001)
Plant Foods:
leaves; wood, bark, or stems; seeds, grains, and nuts.
Predation
- humans (Homo sapiens)
- dingos (Canis lupus dingo)
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, Moll, and Lisle, 2001)
Ecosystem Roles
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)
Key ways these animals impact their ecosystem:
disperses seeds.
Economic Importance for Humans: Negative
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, Moll, and Lisle, 2001)
Ways that these animals might be a problem for humans:
crop pest.
Economic Importance for Humans: Positive
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. (Kangaroo Conservation Center, 2002)
Ways that people benefit from these animals:
ecotourism .
Conservation Status
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)
Other Comments
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, Moll, and Lisle, 2001)
For More Information
Find Macropus dorsalis information at
Contributors
Nancy Shefferly (editor), Animal Diversity Web Staff.
Todd Jewell (author), University of Wisconsin-Stevens Point. Chris Yahnke (editor, instructor), University of Wisconsin Stevens Point.
