Animal Diversity Web

Ge­o­graphic Range

Ground cus­cuses (Pha­langer gym­no­tis) are found on the is­lands of New Guinea, Yapen, Mis­ool, Salawati and the Aru Is­lands. Al­though rare, they have also been sighted in south­ern­most re­gions of New Guinea. ("Ground Cus­cus", 2004; Flan­nery, 2004; Wil­son and Reeder, 2005)

• Biogeographic Regions
• australian
  • native

• Other Geographic Terms
• island endemic

Habi­tat

Pha­langer gym­no­tis oc­cu­pies a va­ri­ety of habi­tats in­clud­ing rain­forests, caves and gar­dens. It is found from sea level up to 2,700 m but is most com­mon at the lower end of its al­ti­tu­di­nal range. Pri­mar­ily ter­res­trial, P. gym­no­tis seeks refuge in dens, which are con­structed in caves, under trees, and along stream beds. It may also be found in cul­ti­vated gar­dens, de­spite close prox­im­ity to hu­mans. ("Ground Cus­cus", 2004; George, 1987; Leary, et al., 2010; Ma­jnep and Bul­mer, 2007; Ra­mono and Nash, 1992)

• Habitat Regions
• temperate
• tropical
• terrestrial

• Terrestrial Biomes
• forest
• rainforest

• Other Habitat Features
• suburban
• caves

• Range elevation

  0 to 2,700 m

  0.00 to ft

Phys­i­cal De­scrip­tion

Pha­langer gym­no­tis has a short, coarse, grey-brown or sil­ver-grey coat that con­tains a dark mid-dor­sal stripe. Fur con­tin­ues down the rump, cov­er­ing the top of the tail. The re­main­der of the tail is cov­ered in small bumpy growths that in­crease fric­tion for grip­ping. Pha­langer gy­mo­tis has lit­tle to no fur on the ears. The lack of fur on the ears and the dark dor­sal stripe dis­tin­guish P. gym­no­tis from other mem­bers of its par­ent genus, Pha­langer. At higher al­ti­tudes, tail fur is more dense and may have a white tip. Sim­i­lar to other mem­bers of Pha­langer, P. gym­no­tis has five dig­its on each foot, in­clud­ing a sin­gle op­pos­able digit on the hind feet. The op­pos­able digit is the only digit lack­ing a claw. Ground cus­cuses vary in mass from 1,500 g to 4,850 g and in length from 310 mm to 539 mm. Tail length makes up a sig­nif­i­cant por­tion of its body length and ranges from 290 mm to 335 mm. In­di­vid­u­als in the north­ern­most part of its range tend to be larger, while in­di­vid­u­als at higher al­ti­tudes are smaller than those a lower al­ti­tude. (Feiler, 1978; Flan­nery, 1995; Flan­nery, 2004; George, 1987; McNab, 2008)

The skulls of Pha­langer gym­no­tis fea­ture a pow­er­ful zy­go­matic arch and promi­nent sagit­tal crest, a nar­row ros­trum, and short paroc­cip­i­tal processes. Pha­langer gym­no­tis is fur­ther di­vided into two sub­species, P. gym­no­tis gym­no­tis and P. gym­no­tis leu­cip­pus, which are dif­fer­en­ti­ated by the wider palate and broader nasals of P. gym­no­tis gym­no­tis. The basal meta­bolic rate of P. gym­no­tis is 518.2 cm^3 oxy­gen/hour. Sex­ual di­mor­phism has not been re­ported in this species. (Feiler, 1978)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Range mass

  1,500.0 to 4,850.0 g

  to oz

• Range length

  310.0 to 539.0 mm

  12.20 to 21.22 in

• Average basal metabolic rate

  518.2 cm3.O2/g/hr

Re­pro­duc­tion

Lit­tle is known about breed­ing in Pha­langer gym­no­tis in the wild. In cap­tive pop­u­la­tions, males court fe­males by chas­ing and bit­ing prospec­tive mates when they are in es­trus. Chas­ing may occur dur­ing day­light hours, but is most com­mon at night, as Pha­langer gym­no­tis is noc­tur­nal. Al­though the mat­ing sys­tem is un­known, it is ei­ther polyg­y­nous or polyg­y­nan­drous, as males have been noted mat­ing with at least two dif­fer­ent fe­males. (Shoe­maker and Crox­ton, 1982)

Pha­langer gym­no­tis mates year round and gives birth to a sin­gle new­born. Al­though ges­ta­tion lasts 13 days, de­layed im­plan­ta­tion may occur, length­en­ing the time be­tween cop­u­la­tion and birth. Fe­males are al­most al­ways found to have a sin­gle young in their pouch, so the breed­ing in­ter­val is as­sumed to cor­re­spond with the length of time to in­de­pen­dence for young. Young re­main in the moth­ers pouch for ap­prox­i­mately three months, at which point they exit the pouch at night. They con­tinue to sleep in the pouch until the age of 5-7 months, when they leave per­ma­nently. Time to wean­ing is un­clear as the con­tin­ued use of the pouch makes wean­ing ob­ser­va­tions dif­fi­cult. ("Ground Cus­cus", 2004; Shoe­maker and Crox­ton, 1982)

• Key Reproductive Features
• iteroparous
• year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• viviparous
• delayed implantation

• Breeding season

  Phalanger gymnotis breed year round

• Range number of offspring

  1 (low)

• Average gestation period

  13 days

• Range time to independence

  5 to 7 months

Young are al­tri­cial and re­main in the mother's pouch, not leav­ing per­ma­nently until the age of 5-7 months. The mother pro­vides milk, but time to wean­ing is un­known. Young exit the pouch first at night, at ap­prox­i­mately 3 months old. The young do not exit dur­ing the day to sleep alone until the age of 4 to 5 months. (Flan­nery, 1995; Shoe­maker and Crox­ton, 1982)

• Parental Investment
• altricial
• female parental care
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • female

Lifes­pan/Longevity

The lifes­pan of wild Pha­langer gym­no­tis is un­known, but in­di­vid­u­als at least 15 years of age have been recorded in cap­tiv­ity. (Flan­nery, 1995; Good­night, et al., 2007)

• Range lifespan
  Status: captivity

  15 (high) years

Be­hav­ior

Out­side of mat­ing sea­son, Pha­langer gym­no­tis is soli­tary and aso­cial, and in­di­vid­u­als are often ag­gres­sive to­ward con­specifics. Fight­ing is com­mon and in­cludes hiss­ing, honk­ing, foot thump­ing and strik­ing op­po­nents with the fore­limbs. Pha­langer gym­no­tis con­structs ter­res­trial dens and for­ages in the mid to lower canopy at night. It gen­er­ally re­mains on low, sta­ble branches while for­ag­ing. Using a flex­i­ble, grip­ping tail and op­pos­able hind thumbs, P. gy­mo­tis is an ac­com­plished climber and can eas­ily tra­verse for­est habi­tats. Pha­langer gym­no­tis is al­most en­tirely noc­tur­nal, how­ever, some in­di­vid­u­als have been seen out­side their dens dur­ing the early morn­ing. ("Ground Cus­cus", 2004; Flan­nery, 1995; Shoe­maker and Crox­ton, 1982; Wil­son and Reeder, 2005)

• Key Behaviors
• arboreal
• scansorial
• terricolous
• nocturnal
• motile
• solitary

Home Range

There is no in­for­ma­tion avail­able re­gard­ing the home range of Pha­langer gym­no­tis.

Com­mu­ni­ca­tion and Per­cep­tion

Pha­langer gym­no­tis uses urine and cloa­cal gland se­cre­tions as scent mark­ers. The scent, pro­duced by both males and fe­males, is said to smell like cof­fee. It likely uses pheromones to de­mar­cate ter­ri­to­r­ial bound­aries and to at­tract po­ten­tial mates. Ground cus­cuses com­mu­ni­cate vo­cally be­fore and dur­ing mat­ing and while fight­ing. While fight­ing, P. gym­no­tis hisses, honks, and foot thumps to com­mu­ni­cate ag­gres­sion. (Flan­nery, 1995; Shoe­maker and Crox­ton, 1982)

• Communication Channels
• acoustic
• chemical

• Other Communication Modes
• pheromones
• scent marks

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

Pha­langer gym­no­tis is pri­mar­ily fru­giv­o­rous, but also con­sumes eggs, seeds, and leaves. It for­ages on the fruit and leaves of plants from nu­mer­ous gen­era, in­clud­ing Elaeo­car­pus, Ficus, Pip­turus, Pan­danus, Oe­nathe, Run­gia, and Ficus odoardii. Fruit is col­lected from trees and from the ground. Fe­male ground cus­cuses have been ob­served fill­ing their pouches with fruit and then re­turn­ing to their home dens where it is stored. (Flan­nery, 1995; Ganslosser and Et­ter-Ganslosser, 1990; Hume, et al., 1997; Mack and Wright, 2005; Wil­son and Reeder, 2005)

• Primary Diet
• herbivore
  • frugivore

• Animal Foods
• eggs

• Plant Foods
• leaves
• seeds, grains, and nuts
• fruit

• Foraging Behavior
• stores or caches food

Pre­da­tion

Other than hu­mans, Pha­langer gym­no­tis has no doc­u­mented preda­tors. Hu­mans prey upon P. gym­no­tis using traps, dogs, and tra­di­tional hunt­ing meth­ods. The noc­tur­nal, soli­tary, and ar­bo­real habits of P. gym­no­tis likely re­duces risk of pre­da­tion. (Leary, et al., 2010; White­head, 2000)

• Known Predators

  • humans Homo sapiens
  • domestic dog Canis lupus familiaris

Ecosys­tem Roles

Fruit dis­per­sion may be in­creased by Pha­langer gym­no­tis. As large fru­gi­vores, ground cus­cuses are one of the only species large enough to dis­perse vir­tu­ally all fruits in the New Guinean rain­for­est. By translo­cat­ing fruit and in­gest­ing seeds, P. gym­no­tis is likely an im­por­tant seed dis­perser through­out its ge­o­graphic range. Par­a­sites spe­cific to this species have not been doc­u­mented. (Mack and Wright, 2005; Shoe­maker and Crox­ton, 1982)

• Ecosystem Impact
• disperses seeds

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Pha­langer gym­no­tis is hunted for its meat year round and is an im­por­tant pro­tein source for rural pop­u­la­tions through­out Papua New Guinea. In some com­mu­ni­ties, P. gym­no­tis is con­sumed only by se­nior el­ders of the com­mu­nity and is con­sid­ered to have med­i­c­i­nal qual­i­ties. (Dwyer, 1982; Leary, et al., 2010; White­head, 2000)

• Positive Impacts
• pet trade
• food
• source of medicine or drug

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Ground cus­cuses may dwell in and around cul­ti­vated gar­dens and eat crops such as sweet pota­toes. (Ma­jnep and Bul­mer, 2007; Ra­mono and Nash, 1992)

• Negative Impacts
• crop pest

Con­ser­va­tion Sta­tus

Al­though hunt­ing has sig­nif­i­cantly re­duced local pop­u­la­tions of Pha­langer gym­no­tis, the species re­mains widely dis­trib­uted and is abun­dant through­out its ge­o­graphic range. It is clas­si­fied as a species of "least con­cern" on the IUCN's Red List of Threat­ened Species. In In­done­sia, P. gym­no­tis is pro­tected by law and can­not be cap­tured, kept or traded. Until re­cently, it was ac­cept­able for only the most se­nior mem­bers of many re­gional tribes in New Guinea to con­sume Pha­langer gym­no­tis, and as a re­sult, was in­fre­quently hunted. As food taboos in rural vil­lages changed dur­ing the 1970s and 1980s, P. gym­no­tis be­came an ac­cept­able food source for mem­bers of al­most all so­cial lev­els re­sult­ing in in­creased pres­sure from hunt­ing. ("Ground Cus­cus", 2004; Flan­nery, 2004; Ma­jnep and Bul­mer, 2007; Ra­mono and Nash, 1992; White­head, 2000)

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  No special status

Other Com­ments

Pha­langer gym­no­tis was for­merly a mem­ber of the genus Spi­lo­cus­cus, but mol­e­c­u­lar data led to its re­clas­si­fi­ca­tion. It in­cludes two sub­species, P. gym­no­tis gym­no­tis and P. gym­no­tis leu­cip­pus. (Feiler, 1978; Os­borne and Chris­tidis, 2002)

Con­trib­u­tors

Colleen Macke (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, Phil Myers (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor, John Berini (ed­i­tor), An­i­mal Di­ver­sity Web Staff.

Ref­er­ences

2004. Ground Cus­cus. Pp. 64-65 in M Hutchins, D Kleiman, V Geist, eds. Grz­imek's An­i­mal Life En­cy­clo­pe­dia, Vol. 13, 2 Edi­tion. Farm­ing­ton Hills, MI: Thom­son Gale.

Dwyer, P. 1982. pp. 529-542. Jour­nal of An­i­mal Ecol­ogy, Vol. 51, No. 2: pp. 529-542.

Feiler, A. 1978. Be­merkun­gen über Pha­langer der "ori­en­talis-Gruppe". Pp. 385-395 in Zo­ol­o­gis­che Ab­hand­lun­gen, Vol. 34 Iss. 25. Leipzig, Ger­many: Akademis­che Ver­lags­ge­sellschaft Geest & Por­tig K.-G..

Flan­nery, T. 1995. Mam­mals of the South-West Pa­cific and Moluc­can Is­lands. Ith­ica, NY: Cor­nell Uni­ver­sity Presss.

Flan­nery, T. 2004. Pos­sums of the world : a mono­graph of Pha­langeroidea. Chatswood, NSW, Aus­tralia: Geo Pro­duc­tions.

Ganslosser, U., R. Et­ter-Ganslosser. 1990. Pha­langers. Pp. 308-309 in S Parker, ed. Grizmek's En­cy­clo­pe­dia of Mam­mals, Vol. 1, 1990 Edi­tion. Hast­ings-on-Hud­son, NY: Mc­Graw-Hill, Inc..

George, G. 1987. Char­ac­ter­i­sa­tion of the Liv­ing Species of Cus­cus. Pp. 513-515 in M Archer, ed. Pos­sums and Opos­sums: Stud­ies in Evo­lu­tion, Vol. 2. Chip­ping Nor­ton, NSW: Sur­rey Beatty & Sons.

Good­night, A., G. Couto, E. Green, M. Bar­rie, G. Myers. 2007. Chemother­apy and Ra­dio­ther­apy for Treat­ment of Cu­ta­neous Lym­phoma in a Ground Cus­cus. Jour­nal of Zoo and Wildlife Med­i­cine, Vol. 39, Iss.3: 472-475.

Hamil­ton, A., M. Springer. 1999. DNA Se­quence Ev­i­dence for Place­ment of the Ground Cus­cus, Pha­langer gym­no­tis , in the Tribe Pha­lan­gerini (Mar­su­pi­alia: Pha­lan­geri­dae). Jour­nal of Mam­malian Evo­lu­tion, Vol. 6 Iss. 1: 1-17.

Hume, I., M. Run­cie, J. Caton. 1997. Di­ges­tive phys­i­ol­ogy of the ground cus­cus (Pha­langer gym­no­tis), a New Guinean pha­lan­gerid mar­su­pial. Aus­tralian Jour­nal of Zo­ol­ogy, Vol. 45 Iss. 6: 561-571.

Leary, T., R. Sin­gadan, J. Men­zies, K. Hel­gen, D. Wright, A. Al­li­son, L. Salas, C. Dick­man. 2010. "Pha­langer gym­no­tis" (On-line). The IUCN Red List of Threat­ened Species. Ac­cessed Feb­ru­ary 26, 2011 at http://​www.​iucnredlist.​org/​apps/​redlist/​details/​16856/​0.

Mack, A., D. Wright. 2005. The Fru­gi­vore Com­mu­nity and the Fruit­ing Plant Flora in a New Guinea Rain­for­est: Iden­ti­fy­ing Keyston Fru­gi­vores. Pp. 185-194 in A Mack, ed. Trop­i­cal Fruits and Fru­gi­vores: The Search for Strong In­ter­ac­tors. Hei­del­berg, Ger­many: Springer Nether­lands.

Ma­jnep, I., R. Bul­mer. 2007. An­i­mals the An­ces­tors Hunted. Be­lair SA, Aus­tralia: Craw­ford House.

McNab, B. 2008. The Com­par­a­tive En­er­get­ics of New Guinean Cus­cuses (Metathe­ria: Pha­lan­geri­dae). Jour­nal of Mam­mal­ogy, Vol. 85 Iss. 5: 1145-1151.

Os­borne, M., L. Chris­tidis. 2002. Mol­e­c­u­lar re­la­tion­ships of the cus­cuses, brush­tail and scaly-tailed pos­sums (Pha­lan­geri­nae). AUS­TRALIAN JOUR­NAL OF ZO­OL­OGY, vol:50 iss:2: 135-149.

Ra­mono, W., S. Nash. 1992. Con­ser­va­tion of Mar­su­pi­als and Monotremes in In­done­sia. Pp. 13-19 in M Kennedy, ed. Aus­tralian Mar­su­pi­als and Monotremes. Gland, Switzer­land: IUCN. Ac­cessed April 06, 2011 at http://​data.​iucn.​org/​dbtw-wpd/​edocs/​1992-026.​pdf.

Shoe­maker, A., J. Crox­ton. 1982. Hus­bandry and Re­pro­duc­tion of the Ground Cus­cus Pha­langer-gym­no­tis in Cap­tiv­ity. In­ter­na­tional Zoo Year­book, Vol. 22 Iss.1: 176-180.

White­head, H. 2000. Food Rules: Hunt­ing, Shar­ing and Taboo­ing Game in Papua New Guinea. Ann Arbor, MI: The Uni­ver­sity of Michi­gan Press.

Wil­son, D., D. Reeder. 2005. Pha­langer gym­no­tis. Pp. 46 in D Wil­son, D Reeder, eds. Mam­mal Species of the World, Vol. 1, 3 Edi­tion. Bal­ti­more, Mary­land: The Johns Hop­kins Uni­ver­sity Press.