Geographic Range
There is only one extant population of Gilbert's potoroos. This population lives
in the Two People's Bay park area of Western Australia.
- Biogeographic Regions
- australian
Habitat
Gilbert's potoroos are entirely terrestrial. In the Two People's Bay park area, the
potoroos hide from predators in the brushy undergrowth. Other members of the genus
Potorous
also prefer living in thick scrub, forest, low bushes, or long grass.
- Habitat Regions
- tropical
- terrestrial
- Terrestrial Biomes
- savanna or grassland
- scrub forest
Physical Description
Gilbert's potoroos measure approximately 558 mm in length, with the tail taking up
158 mm of this total. The short, silky coat of Gilbert's potoroos are grayish-brown,
fading to a reddish-brown color on the back. The under parts are whitish-gray, and
the tail consists of hairs which are gray at the base turning into black at the tips.
The face is long and narrow with a black line running from the nose to the forehead.
- Other Physical Features
- endothermic
- homoiothermic
- bilateral symmetry
Reproduction
The reproductive behavior of Gilbert's potoroos has not yet been studied in detail
by scientists. In
Potorous tridactylus
, the mating system is polygamous. Gilbert's potoroos may share a similar mating
system.
The reproductive behavior of Gilbert's potoroos has not yet been studied in detail by scientists. However, reproduction in Potorous tridactylus has been well documented, and it is likely that Potorous gilbertii is similar in many respects. The following information pertains to P. tridactylus .
Females typically breed two times a year at any time during the year. Litters always
containt a single pup, which is born after a gestation period of approximately 38
days. Females may breed again immediately after giving birth, but the newly conceived
embryo remains dormant and implantation is delayed for at least four and a half months,
or until the first pup dies. Females can breed starting at one year of age. Newborn
pups measure 3/4 inches long at the time of birth. It takes 10 minutes for the pup
to crawl to the mother's pouch. In the pouch, the pup attaches to a teat, where it
remains for two months. Pups continue to suckle until four months of age.
- Key Reproductive Features
- iteroparous
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- fertilization
- viviparous
Parental care in
Potorous gilberti
has not been described. However, as marsupial mammals, some generalizations about
these potoroos can be made. It is likely that most parental care is provided by the
mother, first when the offspring is in her pouch, and later when it becomes more mobile.
Females typically provide their young with protection, grooming, and food while they
are still dependent.
- Parental Investment
- altricial
-
pre-fertilization
- provisioning
-
protecting
- female
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-weaning/fledging
-
provisioning
- female
-
protecting
- female
-
provisioning
Lifespan/Longevity
The lifespan of
Potorous gilbertii
is unknown, but its close relative,
Potorous tridactylus
, is known to live up to 7 years in the wild and up to 12 years in captivity.
Behavior
Little is known about the behavior of Gilbert's potoroos. However,
Potorous tridactylus
, a closely related species, is primarily nocturnal. Males are considered territorial,
but they defend home ranges only when nearby females are in estrus.
Potorous tridactylus
typically lives a in simple nest, with females spending a particularly large amount
of time nesting while they are breeding.
- Key Behaviors
- motile
Home Range
Information on the home ranges of P. gilbertii is not available.
Communication and Perception
The communication patterns of of Gilbert's potoroos are unknown. However, as with
other marsupial mammals, these creatures can perceive visual stimuli, noises, and
smells. It is not known what role scent, visual signals, or vocalizations play in
their communication.
Food Habits
The food habits of Gilbert's Potoroos have not been studied, but one can infer that
it is primarily herbivorous by studying the habits of its relative,
Potorous tridactylus
. Fungi are the major food of
Potorous tridactylus
, although these potoroos will also consume roots, grass, other vegetables, and an
occasionally insect in the summertime. The roots and tubers are dug up with the potoroo's
foreclaws.
Potorous gilbertii
reportedly digs holes in the ground while feeding, so it is likely that it is feeding
on roots or fungi, also.
Predation
Predation by introduced European foxes and feral cats is thought to have played a
major role in the disappearance of Gilbert's potoroos. Researchers believe that the
tiny population of Gilbert's potoroos in Two People's Bay managed to survive because
the park did not employ the usual method of burning vegetation in the park. This extra
brush gave the potoroos a place to hide from predators and allowed them to survive
to the present. In addition, some field researchers report that Natives in Australia
would occasionally kill the potoroos in large numbers.
Ecosystem Roles
The role that Gilbert's potoroos play in their local ecosystem is unknown. However, it can be inferred from their food habits that they modify the vegetation in communities in which they live, and may disturb the soil, influencing plant regeneration.
Economic Importance for Humans: Positive
It is not known whether Gilbert's potoroos have any positive effects on human populations. Although there are reports that P. gilbertii was formerly hunted, because of the species' current restricted distribution, it is not likely that it is a significant resource to indigenous peoples.
Economic Importance for Humans: Negative
It is not known whether Gilbert's potoroos have any negative effects on human populations.
Although the closely related species,
Potorous tridactylus
, is considered a pest by many farmers because it causes damage to potato crops by
scratching for food in the ground, it is not likely that Gilbert's potoroos are a
significant pest because of their restricted distribution.
Conservation Status
Gilbert's potoroos are considered one of Australia's most endangered mammals. Gilbert's
potoroos were presumed extinct until the species was rediscovered in Two People's
Bay in 1994. Many different factors have contributed to the near extinction of this
species. These include predation by introduced foxes and feral cats, disease, poisoned
baits, and loss of land due to grazing cattle. Recent scientific studies indicate
that the single known small population of Gilbert's potoroos has experienced a dramatic,
recent genetic bottleneck. The animals are likely vulnerable to disease due to lack
of genetic variation. To prevent the extinction of Gilbert's potoroos, scientists
estimate that the population must be increased to at least 500 individuals in order
to provide sufficient genetic variation (the current population size is unknown).
To do this, the Two People's Bay area must be conserved, local predators must be controlled,
captive breeding programs must be created, and searches for other possible remaining
populations of Gilbert's potoroos should be conducted.
Additional Links
Contributors
Nancy Shefferly (editor), Animal Diversity Web.
Jennifer Gumas (author), Michigan State University, Barbara Lundrigan (editor, instructor), Michigan State University.
- Australian
-
Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- 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.
- scrub forest
-
scrub forests develop in areas that experience dry seasons.
- 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.
- 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.
- 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).
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- fertilization
-
union of egg and spermatozoan
- internal fertilization
-
fertilization takes place within the female's body
- viviparous
-
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
- 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.
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- motile
-
having the capacity to move from one place to another.
References
Gilbert's Potoroo Action Group, 2004. "Gilbert's Potoroo - Australia's Most Endangered Mammal" (On-line). Accessed June 05, 2007 at http://www.potoroo.org/ .
Harper, F. 1945. Extinct and Vanishing Mammals of the Old World . Baltimore: The Lord Baltimore Press.
Lydekker, R. 1896. A Handbook to the Marsupialia and Monotremata . Edward Lloyd.
Lyne, G. 1967. Marsupials and Monotremes of Australia . Sydney: Halsted Press.
Marlow, B. 1968. Marsupials of Australia . Hong Kong: Jacaranda.
Nowak, R. 1991. Potoroos. Pp. 87-88 in Walker's Mammals of the World , Vol. 1, 5th Edition. Baltimore and London: The Johns Hopkins University Press.
Sinclair, E., B. Costello, J. Courtenay, K. Crandall. 2002. Detecting a genetic bottleneck in Gilbert's Potoroo ( Potorous gilbertii ) (Marsupialia: Potoroidae), inferred form microsatellite and mitochondrial DNA sequence data. Conservations Genetics , 3: 191-196.
Sinclair, E., A. Murch, M. Di Renzo, M. Palermo. 2000. Chromosome morphology in Gilbert's potoroo, Potorous gilbertii (Marsupialia: Potoroidae). Australian Journal of Zoology , 48: 281-287.
IUCN. 1997. "The IUCN Red List of Threatened Species" (On-line ). Accessed 03/09/03 at http://www.redlist.org .