Wallaroo

Characteristics

Common Wallaroos have course, shaggy fur that ranges from reddish-brown to a very dark blue-grey. The species has shorter, wider torsos and shorter limbs (especially hind legs and tails) than other kangaroos and wallaroos. The hind feet are short and broad with roughened soles to provide extra grip. These distinctions are thought to provide advantages in the rocky terrain where they live. Four subspecies of common wallaroo are recognized: eastern, euro, northern, and Barrow Island euro. Subspecies can be distinguished by size, color, and genetic variations.

Species Specifics

Of the three species of wallaroo the common wallaroo is best known, and widest ranging by far. They are the stockiest of the wallaroos and the only species that is found on rocky hillside habitats. The black wallaroo and antilopine wallaroo are both restricted to small ranges in far northern Australia.

Physical Characteristics

As plant eaters, wallaroos have specialized teeth for cropping grass and complex forestomachs, similar to ruminants, for fermentation breakdown of plant fiber.Common Wallaroos have shorter limbs that other kangaroos, which is thought to be an adaptation for balancing and hopping around on the rocky hillsides they frequent. They also have short, broad hind feet with roughened soles to provide grip.

Ecology

Habitat

Typically inhabit mountainous areas with steep escarpments, rocky hills, overhangs, and caves that provide shelter during periods of high temperature. They can also inhabit shrublands, especially near streams, where the shrubs are dense enough to provide shelter from the heat.

Distribution

Widely distributed throughout Australia. The home range of a wallaroo depends on the availability of suitable vegetation. A male wallaroo will make use of a home range of approximately 2.5 square kilometers over the span of a year. A female's home range is much smaller (generally less than 1 square kilometer) so a male's home range may overlap with several females' ranges, giving him more breeding opportunities.

Diet

Wallaroos graze almost exclusively on grass and shrubs

Ecological Web

Primary consumer. It is likely that wallaroos help disperse seeds through their grazing. Young wallaroos are vulnerable to predation by red foxes.

Activity and Behavior

Activity Pattern

Wallaroos generally rest during the hottest part of the day in the shadows created by the overhangs and caves in their rocky habitat. They come out in the evening to graze on vegetation. In the arid extremes of their range, especially during the hottest months of the year, wallaroos will tend toward nocturality.

Behavior

Hopping is a very curious mode of locomotion for large animals, but scientific studies have shown it to be more efficient that quadrupedal running at moderate to high speeds. The energy costs are high when the animal first starts hopping, but as its speed increases the energy costs change little, allowing them to use less energy than a quadrupedal animal when moving at high speeds.

Social Behavior

Wallaroos are generally solitary but will form loose groups of convenience around abundant food sources. These groups are highly flexible in size and composition. Social interaction is most common between young and their mothers. A mother and her mature young will often still rest together during the day and groom each other.

Reproductive Behavior

Wallaroos are opportunistic breeders, able to breed throughout the year when conditions are favorable. They are considered polygynous in that males will mate with more than one female. Males compete for access to females through 'boxing matches,' which mostly involve their powerful feet. After mating, the fetus will develop for an average of 36 days inside the female's uterus before a tiny baby is born. The newborn, at less than an inch long, climbs up the mother's body and into her pouch where it attaches to a nipple and remains for 6 to 7 months.

Offspring

One young born at a time. The joey will spend most of its time in its mother's pouch for the first 9 months, and will rely on the mother for food (nursing and post-weaning) for about 20 months. The mother and offspring usually retain a strong bond even when the young is independent. The father will protect his offspring until they are weaned but does not maintain a relationship beyond that point. A female can have one young in the pouch, one older joey out of the pouch, and one dormant fertilized embryo held in reserve. This embryo will implant and begin development once the joey in the pouch is weaned.

Conservation

Status

Currently listed as Least Concern by the IUCN. Common Wallaroo populations are stable and the animals are widespread and relatively common in appropriate habitats.

Historical

The first species clearly related to modern wallaroos appeared in the Pliocene period, 4-5 million years ago. Wallaroo and kangaroo relatives were able to radiate widely across Australia with the drying of the continent and expansion of grasslands that occurred during this same period. The extinction of giant kangaroos of the megafauna era is thought to coincide with the arrival of Aboriginal people to the continent, between 40,000 and 60,000 years ago. European explorers would have been greeted by our modern day wallaroo, and have not much affected their overall population. Wallaroos have lost habitat to the building of cities, but have gained habitat in areas that were once too arid for them to survive but are now suitable habitat due to water being provided for agricultural animals.

Current Threats

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