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Macropus bernardusblack wallaroo

By Evan Hyatt

Geographic Range

Black Wallaroos are found in limited areas on the sandstone escarpment and plateau of the western edge of Arnhem Land, a region of northern Australia located to the west of the Gulf of Carpentaria.

Habitat

These animals usually occur in a wide range of vegetation types varying from closed forests to open Eucalyptus forests to hummock grasslands and heaths. In most cases, they are found in areas that have large boulders in the landscape.

Physical Description

The Black Wallaroo is one of the smallest species in the kangaroo family. They are roughly two thirds the size of northern wallaroos. They range from .8 meters tall in females, up to about 1 meter tall in males. The name comes from the color of the males, which are a sooty brown to glossy black, while females are a dark brown to grey color. The ears are shorter than nothern wallaroos. Unlike kangaroos where the muzzle is covered with hair, the black wallaroo's nose is completely naked.

  • Range mass
    13 to 22 kg
    28.63 to 48.46 lb

Reproduction

The Black Wallaroo, similar to other wallaroos, breed continously throughout the year under good conditions. Females often increase their area of activity in order to attract the largest most dominant male in that area. Reproduction often depends on lactation to nourish the underdeveloped young, which depends on the availability of food resources.

The female gestates between 31 and 36 days, and once born, the young, which are only a few centimeters in length, find their way to the mother's pouch and attach themselves to a nipple. A young is attached to the nipple until approximately 4 months of age, during which time the mother may be carrying another embryo in the uterus in an "embryonic diapause" or halted state of development. After the young detach themselves from the nipple, they continue to live in the pouch, but the mother is able to give birth to the other baby, which has resumed uterine development. The female wallaroo is then able to support two different aged joeys in the pouch simultaneously.

  • Breeding season
    All year
  • Range gestation period
    31 to 36 days
  • Average weaning age
    6 months

The young emerge from the pouch after about 6 months. The mother can control the opening of the pouch with muscles to either keep the joey inside when the mother is alarmed or to get the joey to exit the pouch. Even after the joey is not living in the pouch anymore, it returns to the pouch to suckle for many months.

Lifespan/Longevity

  • Average lifespan
    Status: captivity
    11.8 years
    AnAge

Behavior

The Black Wallaroo is a rather solitary animal, except while breeding; with no more than three individuals being found in a group (usually an adult male and female, along with a large young) Mothers often groom their young while it is still suckling but after it has exited the pouch.

Aggressive behaviors are shown between males, but rarely lead to injury, and usually end quickly. Threatening displays include stiff-legged walking, pulling on grass or bushes, and upright postures.

These animals are extremely shy, running until out of sight if approached. This makes them difficult to study, thus making the black wallaroo probably the least known of the kangaroos.

Communication and Perception

Food Habits

Black Wallaroos are grazers, who spend between 7 and 14 hours a day feeding, depending on the season. They are most active at dawn and dusk, but relatively inactive during the middle of both the day and night when they are resting. They eat mostly grasses and shrubs but will occasionally eat other plants.

  • Plant Foods
  • leaves

Predation

The Black Wallaroo uses camoflauge to hide from predators. They are also rather quick, and they rely on speed to escape predators.

Predators include eagles, which take the young, dingos, foxes, crocodiles, and humans.

Economic Importance for Humans: Positive

There are not many positive benefits to humans mainly because these animals live in such a small area of Australia. They do not intrude on farm land, and do not disturb crops. They are the only type of kangaroo which is not good to eat; the meat has a rank and unpleasant smell and taste.

Conservation Status

The Black Wallaroo occurs naturally in a very small area, so it is important to protect this area. A large part of their habitat is located in the Kakadu National Park in Australia, which is already protected. The largest threat to the survival of the species is the change of fire patterns in their home range, which has altered the flora composition in the area where they live. Little is known about the abundance or population of this species, however, which makes it hard to determine if they are threatened by this change of fire patterns.

Other Comments

Wallaroo actually means, "rock kangaroo."

Contributors

Evan Hyatt (author), University of Michigan-Ann Arbor, Bret Weinstein (editor), University of Michigan-Ann Arbor.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

altricial

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.

bilateral symmetry

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.

chemical

uses smells or other chemicals to communicate

delayed implantation

in mammals, a condition in which a fertilized egg reaches the uterus but delays its implantation in the uterine lining, sometimes for several months.

endothermic

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.

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

folivore

an animal that mainly eats leaves.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

herbivore

An animal that eats mainly plants or parts of plants.

internal fertilization

fertilization takes place within the female's body

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

temperate

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).

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

References

Dr. Ann, May 20, 2000. "Australian Wildlife" (On-line). Accessed 10-08-01 at http://www.australianwildlife.com.au/default.htm.

Maxwell, S., A. Burbidge, K. Morris. December, 1996. "Action Plan for Australian Marsupials and Monotremes" (On-line). Accessed 10-08-01 at http://www.ea.gov.au/biodiversity/threatened/action/marsupials/26.html.

Strahan, R. 1995. Mammals of Australia. Chatswood, New South Wales: Reed Books.

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