Thylogale thetisred-necked pademelon

Geographic Range

Red-necked pademelons (Thylogale thetis) are only found in parts of eastern Australia. They range from eastern Queensland to just below mid-coast of New South Wales. (Nowak, 1995)

Habitat

The habitat of red-necked pademelons consists of rainforests, thick scrub or grassland areas, and eucalyptus forests. (Wahungu, et al., 2001)

Physical Description

Red-necked pademelons have a head and body length of 290 to 630 mm, with a tail length of 270 to 510 mm. They exibit sexual dimorphism in size, with the males weighing approximately 7 kg compared to the average female weight of 3.8 kg. ("Thylogale thetis (Red-necked pademelon)", 2002; Nowak, 1995)

Red-necked pademelons are grizzled gray in color above with a light hip stripe often present. The short tail of these animals is only lightly furred. It is also thick and rounded. (Nowak, 1995)

  • Sexual Dimorphism
  • male larger
  • Average mass
    females-3.8, males-7 kg
    lb
  • Average mass
    3800 g
    133.92 oz
    AnAge
  • Range length
    290 to 630 mm
    11.42 to 24.80 in

Reproduction

Little is known about mating systems in pademelons. Males in captivity tend to be somewhat aggressive toward one another. Taken with the pronounced sexual dimorphism in this species, this is suggestive of polygyny. Polygyny is common in macropods. (Nowak, 1995)

It has been recorded that female red-necked pademelons when in oestrus will be found around larger males, suggesting active mate choice by females. (Ord, et al., 1999)

Red-necked pademelons reach sexual maturity at about 18 months of age. Reproduction occurs in the autumn and spring in the north, and during the summer in the south. These pademelons usually give birth to a single young, although twins have been recorded in the genus. (Nowak, 1995)

Embryonic diapause is known to occur in red-necked pademelons. Embryonic diapause is when the division of the cells in the embryo stops when there are about 100 cells. This "started" but unfinished embryo is held in the uterus until conditions are right for development to continue. This allows for an embryo to be in the uterus while a mother is weaning another joey in the pouch. Once the nursing joey is weaned, development of the embryo can continue. The embryo experiences a short "actual" gestation period of approximately 30 days, but can stay in the pouch for up to 6 1/2 months. (Nowak, 1995)

In all marsupials, the young are altricial, and must make their way from the birth canal into a pouch, where they receive milk from the mother and complete their development. (Nowak, 1995; Nowak, 1995)

In another member of the genus, T. billardierii, a joey stays in the pouch for 202 days, and weaning occurs about 4 months after the young permanently leave the pouch. Sexual maturity is slightly earlier in T. billardierii than in T. thetis, and it is possible that these other developmental events occur slightly later in the latter species as well. (Nowak, 1995)

  • Breeding interval
    These pademelons are apparently able to produce offspring once per year.
  • Breeding season
    Breeding occurs during the autumn and spring in the north, and during summer in the south.
  • Range number of offspring
    1 to 2
  • Average number of offspring
    1
  • Average number of offspring
    1
    AnAge
  • Average gestation period
    30 days
  • Average age at sexual or reproductive maturity (female)
    18 months
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    555 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    18 months

Parental care in this species has not been detailed in the literature. However, like other macropods, it is likely that the bulk of parental care is performed by the mother. Mothers nurse their joeys in a pouch, providing them with protection and grooming, until the young have developed enough to leave the pouch. Leaving the pouch permanently is a slow process, and during that time, the mother continues to nurse, groom, and protect her offspring. It is likey that T. thetis is like other macropods in this respect. (Nowak, 1995)

  • 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
    • provisioning
      • female

Lifespan/Longevity

I found no documented information on this topic.

  • Average lifespan
    Status: captivity
    9 years
    AnAge

Behavior

Red-necked pademelons are solitary animals, sometimes forming small groups. They will sleep during most of the day in leaf litter and may bask in the sun when cold. (Nowak, 1995)

Red-necked pademelons rely on saltatorial locomotion for movement. They have an increased muscle fiber to tendon area ratio in their ankles. The tendons may be size or function dependent, and the strength of these tendons may limit locomotion. Thylogale thetis may also travel on all four legs and drag its tail behind, but, as in other macropods, this type of locomotion is reserved for slower travel. (Bennett, 2000; Nowak, 1995)

Home Range

Thylogale thetis has a home range of about 5 to 30 ha. ("Thylogale thetis (Red-necked pademelon)", 2002)

Communication and Perception

Red-necked pademelons communicate with one another using different clicks and by thumping their hind feet. As mammals, they also have visual capability, and probably use some visual signals, such as body postures, to communicate. Although not specifically reported for this species, it is likely that there are some scent cues, especially related to reproduction. Tactile communication occurs between mothers and their young, as well as between mates. (Nowak, 1995; "Red-necked Pademelon-Thylogale thetis ", 2000)

Food Habits

Food consists of grass, leaves, roots and bark. Foraging behaviors of red-necked pademelons consist of feeding on forest edge at night. This apparently reduces their risk of falling prey to diurnal predators. A larger group size increases the range of feeding from forest cover. (Wahungu, et al., 2001)

  • Plant Foods
  • leaves
  • roots and tubers
  • wood, bark, or stems

Predation

Predators of red-necked pademelons are the introduced fox and the dingo, and possibly even large birds of prey. They decrease predation risk by foraging at night. ("Thylogale thetis (Red-necked pademelon)", 2002)

Ecosystem Roles

The major ecosystem role that red-necked pademelons play is that they are food for their predators. Through their foraging habits, they are likely to impact the growth of vegetation. ("Thylogale thetis (Red-necked pademelon)", 2002)

Economic Importance for Humans: Positive

Red-necked pademelons have been important for ecotourism in the areas in which they occur. ("Thylogale thetis (Red-necked pademelon)", 2002)

Economic Importance for Humans: Negative

There is no documented information about red-necked pademelons having a negative effect.

Conservation Status

The distribution of red-necked pademelons has decreased in Australia due to clearance of native vegetation for agriculture, dairying, and forestry. Even with this, the species is common in some areas. (Nowak, 1995)

The red-necked pademelon is not currently protected under CITES or IUCN.

Other Comments

Red-necked pademelon mothers may throw the joey out of their pouch during hard times to ensure that their own survival. This is a type of infanticide, but probably has a low cost to the mother because she is probably already pregnant with another offspring in embryonic diapause, just waiting for conditions to improve before proceding in its development. ("Thylogale thetis (Red-necked pademelon)", 2002)

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Toni Lynn Wainio (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor, instructor), University of Wisconsin-Stevens Point.

Glossary

Australian

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

World Map

acoustic

uses sound to communicate

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

ecotourism

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.

embryonic diapause

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)

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.

fertilization

union of egg and spermatozoan

folivore

an animal that mainly eats leaves.

herbivore

An animal that eats mainly plants or parts of plants.

iteroparous

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).

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.

nocturnal

active during the night

polygynous

having more than one female as a mate at one time

rainforest

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.

saltatorial

specialized for leaping or bounding locomotion; jumps or hops.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

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

solitary

lives alone

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).

terrestrial

Living on the ground.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5? N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

viviparous

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

References

University of Queensland. 2000. "Red-necked Pademelon-Thylogale thetis " (On-line). Mammals of Lamington National Park. Accessed June 23, 2004 at http://lamington.nrsm.uq.edu.au/MainMenu.html.

Hobart & William Smith Colleges and Union College. 2002. "Thylogale thetis (Red-necked pademelon)" (On-line). 2001 QUEENSLAND TERM WILDLIFE FIELD GUIDE. Accessed June 23, 2004 at http://people.hws.edu/mitchell/fguide/show.asp?ID=87.

Bennett, M. 2000. Unifying principles in terrestrial locomotion: Do hopping Australian marsupials fit in?. Physiological-and-Biochemical-Zoology, 73: 726-735.

Nowak, R. 1995. "Pademelons" (On-line). Walker's Mammals of the World Online, V. 5.1. Accessed October 14, 2002 at http://www.press.jhu.edu/books/walkers_mammals_of_the_world/marsupialia/marsupialia.macropodidae.thylogale.html.

Ord, T., C. Evans, D. Cooper. 1999. Nocturnal behaviour of the parma wallaby, Macropus parma (Marsupialia:Macropodoidea). Australian Journal of Zoology, 47: 155-167.

Wahungu, G., C. Catterall, M. Olsen. 2001. Predator avoidance, feeding and habitat use in the red-necked pademelon, *Thylogale thetis*, at rainforest edges. Australian Journal of Zoology, 49: 45-58.