By Peter Hundt
Geographic Range
The range of endangered bridled nail-tailed wallabies has been reduced to 11,470 hectares in the Taunton Scientific Reserve in northeastern Austalia. This reserve is located near the city of Dingo in Central Queensland. (Hendrikz and Johnson, 1999)
Biogeographic Regions:
australian 
(native ).
Habitat
At one time, Onychogalea fraenata inhabited the semi-arid region of eastern Australia. This region is made up mainly of Acacia shrub land and grassy woodlands. Now it is only found in Taunton National Park although a population has recently been released into Idalia National Park. (Lundie-Jenkins, 2001)
These animals are found in the following types of habitat:
tropical ; terrestrial .
Terrestrial Biomes:
savanna or grassland ; scrub forest .
Physical Description
(8.8 to 17.6 lbs)
(31.1 to 56.3 in)
Onychogalea fraenata is named for the white "bridle" line that starts on the center of the neck and goes around the shoulders and ends at the forearms on each side. A black stripe runs dorsally across the whole body. (Lundie-Jenkins, 2001)
Males weigh between 5 and 8 kg, whereas females weigh from 4 to 5 kg. The head and body length of this species is 430 to 700 mm, with the tail contributing an additional 360 to 730 mm to the total length. (Lundie-Jenkins, 2001; Nowak, 1999)
The genus Onychogalea gets its common name, nail tailed wallabies, from a small, horny spur (3 to 6 mm) at the end of the tail. This "nail" is partially concealed by hair. (Lundie-Jenkins, 2001; Nowak, 1999)
Some key physical features:
endothermic ; bilateral symmetry .
Sexual dimorphism: male larger.
Reproduction
Females of this species are capable of producing three offspring per year.
Breeding is not seasonal when conditions are favorable.
Onychogalea fraenata mates polygynously. Males roam widely, checking nonestrus females briefly by smell. They may accompany estrus females that they encounter for up to a week. Groups of males sometimes accumulate around receptive females. These males follow females roughly in order of body weight, and the largest male appears to defend access to the female. (Lara and Fisher, 1999)
The main difference between O. fraenata and most other terrestrial macropods is that there is no dominance hierarchy prior to encounter. Because O. fraenata is solitary, males cannot establish dominance relationships until they have encountered one another. However, these animals can recognize dominance from prior encounters, so rather than waste energy on another combat sequence they behave toward one another based upon the hierarchy determined in previousl encounters. (Lara and Fisher, 1999)
Copulation times may exceed more than ninety minutes, which is longer than most macropods. (Lara and Fisher, 1999)
During estrus cycles, females increase their home range. They also increase their activity, and are more attractive to males prior to mating. Such features are not unique to this species, but are common in most solitary mammals. (Lara and Fisher, 1999)
Male that are the largest in size and have the largest home ranges have higher copulatory success. Males and females participate in mate chasing. Because females do not appear to be attempting to evade the males, based on their slow speed and repetitive movements, this appears to be some sort of courtship behavior. (Lara and Fisher, 1999)
Mating systems:
polygynous .
Onychogalea fraenata has been studied both in captivity and wild. In captivity, these animals breed continuously. Females have an average estrous cycle of 32.6 days and gestation lasts an average 23.6 days. Newborns spend 119 to 126 days in the pouch. Males reach sexual maturity in about 270 days, whereas females reach it in 136 days. (Lara and Fisher, 1999; Lundie-Jenkins, 2001)
If conditions are suitable in the wild, bridled nailtail wallabies can raise up to three young per year and mate continuously throughout the year. (Lara and Fisher, 1999; Lundie-Jenkins, 2001)
Key reproductive features:
iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous .
Like other macropods, O. fraenata, have extremely altricial young. Young are born excessively underdeveloped, and must complete their delopment inside the mother's pouch, attached to her nipple. Based on the mating system, it is unlikely that there is paretal care provided by males. (Lara and Fisher, 1999)
Parental investment:
no parental involvement; altricial ; pre-fertilization (protecting: female); pre-hatching/birth (provisioning: female, protecting: female); pre-weaning/fledging (provisioning: female, protecting: female); pre-independence (protecting: female).
Lifespan/Longevity
Not much information is available regarding the lifespan/longevity of this species. However, individuals in captivity have lived 5.5 years. (Lundie-Jenkins, 2001)
Behavior
Onychogalea fraenata is a solitary animal and is nocturnal, emerging at night to feed on forbes and grasses. During the day it spends most of its time underneath grass or a bush in a small shallow nest. (Lundie-Jenkins, 2001)
Home Range
Male home ranges are about 60 ha while females home ranges are about 25 ha. Movement is very restricted during the day, but at night movement increases to between 10 and 200 meters per hour. (Lundie-Jenkins, 2001)
Key behaviors:
terricolous; saltatorial ; nocturnal ; motile ; sedentary ; solitary ; dominance hierarchies .
Communication and Perception
Very little information was available on communication in O. fraenata. However, some generalizations can be made, based on what we know of mammals in general, and other macropods in particular.
These animals are known to transmit information through scent cues, especially when females are in estrous. Males determine the readiness of females to mate based upon their smell. In addition, there is some visual and tactile communication during mating, based upon chasing behavior and the mating process itself. (Lara and Fisher, 1999; Lundie-Jenkins, 2001)
Other macropods are known to vocalize, and it is likely that O. fraenata is similar. (Nowak, 1999)
Food Habits
Onychogalea fraenata feeds on a diverse selection of forbes, grasses, and woody browse. During observation in Taunton National Park, these foods were selected by the animals: The herbaceous forb Portulaca oleraceae, pigweeds such as Helipterum spp., daisies such as Trianthema triquetra and Zalea galericulata, and grasses such as Sporobolus carolii, Chloris divaricata, Dactyloctenium radulans, and Bothriochloa bladhi. (Lundie-Jenkins, 2001)
Plant Foods:
leaves.
Predation
- European red foxes (Vulpes vulpes)
- dingos (Canis lupus dingo)
No information on anti-predator adaptations was available for O. fraenata. Native dingoes may be predators of these animals. Exotic carnivores such as red foxes may prey on these animals. (Lundie-Jenkins, 2001)
Ecosystem Roles
Onychogalea fraenata feed on a variety of plants and may affect plant communities in then region. (Lundie-Jenkins, 2001)
Economic Importance for Humans: Negative
This species has little effect on humans.
Economic Importance for Humans: Positive
Because nail-tailed wallabies are only found in national parks, they may be important for ecotourism. (Lundie-Jenkins, 2001)
Ways that people benefit from these animals:
ecotourism .
Conservation Status
Onychogalea fraenata is part of a large recovery plan. The number of these wallabies has declined due to competition with domestic animals, habitat destruction, and the introduction of carnivores (mainly foxes and dingos). Onychogalea fraenata has already been successfully reintroduced into the Idalia National Park and there are plans for other reintroductions from animals in captive breeding programs. The species is listed as Endangered by IUCN and is on Appendix I of CITES. (Lundie-Jenkins, 2001)
Contributors
Nancy Shefferly (editor), Animal Diversity Web Staff.
Peter Hundt (author), University of Wisconsin-Stevens Point. Chris Yahnke (editor, instructor), University of Wisconsin Stevens Point.
