Animal Diversity Web

Ge­o­graphic Range

The moun­tain pygmy pos­sum, Bur­ramys parvus, lives in the alps of Vic­to­ria and New South Wales, Aus­tralia. More specif­i­cally, it is found atop the Mount Bo­gong, Mount Loch and Mount Hig­gin­botham moun­tain ranges of Vic­to­ria. In New South Wales, it is found pre­dom­i­nantly in the moun­tain ranges of Kosciusko Na­tional Park, which in­clude Mount Townsend, Mount Kosciusko, and Mount Blue Cow (Broome and Mansergh 1994). Bur­ramys parvus ranges in el­e­va­tion from 1400m to 2230m (Stra­han 1995).

• Biogeographic Regions
• australian
  • native

Habi­tat

Bur­ramys parvus lives in a cold, wet cli­mate. Snow is pos­si­ble year round, but is most fre­quent be­tween June and Sep­tem­ber. When snow is not blan­ket­ing the ground, rain and pow­er­ful winds are typ­i­cal. The New South Wales and Vic­to­rian alps an­nual rain­fall is greater than 1500mm. The al­ti­tude of the alps causes tem­per­a­tures to be low, sel­dom ex­ceed­ing 10 de­grees cel­sius from May to Sep­tem­ber (Broome and Mansergh 1994). The habi­tat of this species can be de­scribed as a boul­der­field. Re­cur­rent wet­ting and freez­ing of water on the rock sur­face­shas led to frag­men­ta­tion of boul­ders. These frag­ments pro­vide nec­es­sary pro­tec­tion from the harsh cli­matic con­di­tions and alpine preda­tors. Bur­ramys parvus often has been found nest­ing among the crevices. Plants es­tab­lish in shal­low frag­ments, pro­vid­ing the moun­tain pygmy pos­sum with plen­ti­ful re­sources (Stra­han 1995). These plants are typ­i­cally low shrubs with grasses in­ter­mixed (Stra­han 1983).

• Terrestrial Biomes
• tundra
• mountains

Phys­i­cal De­scrip­tion

Bur­ramys parvus is a small, ro­dent­like mar­su­pial. Both sexes are about 110mm in head and body length, with males being slightly longer and heav­ier than fe­males. The tail of B. parvus is pre­hen­sile, rang­ing from 140mm in fe­males to 148mm in males (Stra­han 1983). The fur is fine, but dense. The dor­sal side is grey, with a darker sec­tion at the back and head mid­line. The ven­tral sur­face is light cream, with males de­vel­op­ing a bright fawn-or­ange in breed­ing sea­son. The forepaws are dex­ter­ous, eas­ily able to ma­nip­u­late food, while on the hind­foot the hal­lux aids in climb­ing (Broome and Mansergh 1994).

• Other Physical Features
• endothermic
• bilateral symmetry

• Average mass

  45 g

  1.59 oz

  AnAge

• Average basal metabolic rate

  0.205 W

  AnAge

Re­pro­duc­tion

Bur­ramys parvus fol­lows a low fe­cun­dity, high longevity life strat­egy. The moun­tain pygmy pos­sum has a non-breed­ing sea­son from Jan­u­ary-April, when it gain sweight for the com­ing win­ter and the young dis­perse. The in­ac­tive sea­son, from May-Sep­tem­ber, is hi­ber­na­tion sea­son for B. parvus. From Sep­tem­ber through De­cem­ber, B. parvus is in an ac­tive sea­son of breed­ing. B. parvus fe­males are polye­strous but lim­ited to one lit­ter per year by the need to store fat re­serves for hi­ber­na­tion. With­out suf­fi­cient fat, the fe­males die. In re­sponse to fat re­serve lim­i­ta­tions, B. parvus syn­chro­nizes its re­pro­duc­tion with spring, when nu­tri­ent rich Bo­gong moths are abun­dant. Breed­ing oc­curs an­nu­ally for many con­sec­u­tive years. Re­pro­duc­ing fe­males have been found up to 12 years of age, which makes them one of the longest lived small ter­res­trial mam­mals.

Stud­ies have suc­cess­fully mapped out the re­pro­duc­tive time­line of the moun­tain pygmy pos­sum (Mansergh and Scotts 1990). Mat­ing oc­curs be­tween late Sep­tem­ber and mid Oc­to­ber. Fe­male es­trous lasts ~20 days. After fer­til­iza­tion, a ges­ta­tion pe­riod of 13-16 days en­sues, fol­lowed by birth in the last week of Oc­to­ber of four al­tri­cial young (Mansergh and Scotts 1990). The young have well de­vel­oped fore­limbs and heads for trav­el­ing from the cloaca to the pouch. The fe­male cleans a trail for the young to the pouch, where the young at­tach to a teat (Broome and Mansergh 1994). Fre­quently the fe­male bear smore than four young, lead­ing to more off­spring than teats. Under these cir­cum­stances, the 'slow­est' young will not have a teat when it ar­rives in the pouch, and will die. The lac­ta­tion pe­riod lasts 30 days, with a sub­se­quent nest­ing pe­riod of 30-35 days (Stra­han 1995). The young are fully weaned and in­de­pen­dent after 65 days. Young dis­perse be­tween Jan­u­ary and March (Lee and Cock­burn 1985). At ap­prox­i­mately 1 year of age, the young begin mat­ing. Only 50% of the re­pro­duc­ing young will sur­vive, due to the in­abil­ity of younger B. parvus to main­tain fat re­serves for hi­ber­na­tion (Mansergh et al. 1990). By their sec­ond sum­mer, young are fully ca­pa­ble of sus­tain­ing them­selves for both ac­tiv­i­ties (Stra­han 1995).

• Key Reproductive Features
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual

• Average number of offspring

  3.5

  AnAge

• Average gestation period

  15 days

  AnAge

• Average age at sexual or reproductive maturity (female)
  Sex: female

  320 days

  AnAge

• Average age at sexual or reproductive maturity (male)
  Sex: male

  320 days

  AnAge

Lifes­pan/Longevity

• Average lifespan
  Status: wild

  4.0 years

  Max Planck Institute for Demographic Research

• Average lifespan
  Status: captivity

  7.0 years

  Max Planck Institute for Demographic Research

Be­hav­ior

The moun­tain pygmy pos­sum is a calm, so­cial an­i­mal, rarely en­gag­ing in com­pe­ti­tion for space or food. Bur­ramys parvus is se­cre­tive and noc­tur­nal. Dur­ing the day, it sleeps curled in a ball to re­tain heat. In cap­tiv­ity, its tem­pra­ment is much the same. Moun­tain pygmy pos­sums have been seen run­ning over the backs of each other with lit­tle dis­tur­bance. They also seem to so­cially groom each other. Only when dis­tressed does B. parvus make a low gut­tural vo­cal­iza­tion (Broome and Mansergh 1994). Mat­ing be­hav­ior of B. parvus is cued by sev­eral fac­tors, in­clud­ing spring equinox, ar­rival of Bo­gong moths, male en­croach­ment into natal areas, and dis­ap­pear­ance of snow (Mansergh and Scotts 1990). The be­hav­ior of B. parvus has a char­ac­ter­is­tic pat­tern, with the male first pur­su­ing a fe­male and sniff­ing her anal re­gion. If the fe­male chooses to mate, she al­lows him to mount and clasp her flanks. Cop­u­la­tion lasts sev­eral min­utes, after which the male leaves. The fe­male may show ex­treme post-cop­u­la­tory ag­gres­sion to­wards the male if he chooses to stay in the vicin­ity after cop­u­la­tion (Broome and Mansergh 1994).

After birth and growth of young males, fe­males are ag­gres­sive to­wards them and force them to leave the natal area. Older males leave first, fol­lowed by ju­ve­nile males and some­times ju­ve­nile fe­males. Over time, the sex ratio of a natal area be­comes fe­male bi­ased (Stra­han 1995). The seden­tary fe­males have a bet­ter re­source pool than the dis­persed males, lead­ing to in­creased longevity of fe­males (Mansergh and Scotts 1990). In fact, fe­males are four to five times more likely to sur­vive the win­ter than males (Menkhorst 1995). This type of so­cial or­ga­ni­za­tion has been termed ma­tri­archi­cal re­source de­fence polyg­yny (Mansergh and Scotts 1990).

Fe­male's natal areas have com­mu­nal nest­ing sites and over­lap­ping home ranges. Older fe­males tend to share their ranges with up to 10 younger fe­males. It is likely that the younger fe­males are ge­netic de­scen­dants of the older fe­male. Only dur­ing nightly for­ages do the fe­males leave the natal area. Since the natal area is in the higher el­e­va­tions, where food is more abun­dant, these dis­per­sals are rel­a­tively short dis­tances (Broome and Mansergh 1994).

Males have less struc­tured home ranges. When not in­vad­ing the fe­male's range to mate, the males are no­mads, for­ag­ing dur­ing the evening over broad ex­panses of nu­tri­ent poor re­sources (Broome and Mansergh 1994). Their for­ag­ing dis­tances can reach rel­a­tively long dis­tances, de­creas­ing their like­li­hood of sur­vival due to preda­tors and in­suf­fi­cient nu­tri­ents.

• Key Behaviors
• motile

Com­mu­ni­ca­tion and Per­cep­tion

• Perception Channels
• tactile
• chemical

Food Habits

The moun­tain pygmy pos­sum is best de­scribed as an om­ni­vore-in­sec­ti­vore-grani­vore- fru­gi­vore. While eat­ing habits of B. parvus are di­verse, the di­ver­sity of prey is low, mak­ing B. parvus a spe­cial­ized feeder, ac­cord­ing to the sea­son. Dur­ing the 'ac­tive sea­son' from Oc­to­ber-April, B. parvus' diet con­tains high en­ergy food. Dur­ing this pe­riod, B. parvus is an om­ni­vore and in­sec­ti­vore, feed­ing heav­ily upon the Bo­gong moth (Agro­tis in­fusa), which mi­grates yearly to the Aus­tralian alps for breed­ing. The yearly mi­gra­tion of the moth pro­vides a pre­dictable, en­ergy rich and abun­dant food sup­ply for B. parvus. Stud­ies con­ducted by Mansergh and as­so­ci­ates (1990) re­veal that the Bo­gong moth con­sti­tutes over 33% of the total 'ac­tive sea­son' diet of B. parvus. A later study by Smith and as­so­ci­ates (1992) re­ported that the moth may ac­tu­ally be the only di­etary item dur­ing the re­pro­duc­tive sea­son (Oc­to­ber-De­cem­ber) of B. parvus. It has been found that fe­males take a higher per­cent­age of Bo­gong moths than males, due to the con­cur­rent breed­ing sea­son and ad­di­tional nu­tri­tional sup­ple­ments re­quired to raise off­spring (Smith and Broome 1992). Other in­sects, con­sumed in sparse quan­ti­ties, are cater­pil­lars, mil­li­pedes, bee­tles and spi­ders (Broome and Mansergh 1994). As the ac­tive sea­son pro­gresses, the abun­dance of Bo­gong moths de­creases, lead­ing to a di­etary switch from moths to seeds and berries. The moun­tain pygmy pos­sum prefers the seeds of habi­tat spe­cific species such as Moun­tain Plum-pine, Ram­bling Bram­ble, and Snow Beard-heath, dur­ing the months of Jan­u­ary-April (Broome and Mansergh 1994).

Dur­ing the 'non-ac­tive', or hi­ber­na­tion sea­son, B. parvus caches seeds and berries, which con­sti­tute over 75% of their diet from May-Oc­to­ber (Broome and Mansergh 1994). The moun­tain pygmy pos­sum is the only mar­su­pial found to cache non-per­ish­able food items (Menkhorst 1995).

Bur­ramys parvus is well adapted to its spe­cial­ized diet. The moun­tain pygmy pos­sum has agile fore­limbs that per­mit ma­nip­u­la­tion of seeds, berries and in­sects. The hard coats of seeds and in­sect ex­oskele­tons are eas­ily opened with a pla­giaula­coid pre­mo­lar. Bur­ramys parvus uses its procum­bent lower in­cisors to scoop out the in­te­rior of the seed or in­sect.

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Con­ser­va­tion­ists con­sider Bur­ramys parvus eco­nom­i­cally im­por­tant to re­search. The con­fined habi­tat and home ranges of B. parvus make it ideal for stud­ies on wildlife man­ag­ment, es­pe­cially those with rapidly de­clin­ing pop­u­la­tion. By es­tab­lish­ing broad range meth­ods to ef­fec­tively treat an­i­mal pop­u­la­tions, less mon­e­tary funds will be re­quired for species spe­cific method de­vel­op­ment.

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Ski in­dus­tries some­times feel their land ac­quis­tion op­por­tu­ni­ties are being thwarted by ef­forts aimed at con­ser­va­tion of B. parvus habi­tats. Re­cent con­ser­va­tion ef­forts (tun­nel build­ing) for B. parvus have been tol­er­ated and ac­cepted by es­tab­lished ski re­sorts. How­ever, it has be­come in­creas­ingly dif­fi­cult for new en­tre­peneurs in the in­dus­try to find un­pro­tected por­tions of B. parvus habi­tat to de­velop.

Con­ser­va­tion Sta­tus

The Moun­tain Pygmy Pos­sum lives in the Aus­tralian alps, where the ski in­dus­try has been grow­ing since the mid 1950's. Lev­el­ing and groom­ing of land for ski trails has greatly af­fected the amount of avail­able habi­tat for B. parvus. While B. parvus of­tens makes its home in ski lodge foun­da­tions, the dis­per­sal of males to and from the natal site has be­come in­creas­ingly dif­fi­cult. Also prob­lem­atic is the de­struc­tion of trees and shrubs, which B. parvus uses for food. Suf­fi­cient field data were col­lected in 1979 by Ken Nor­ris, an Aus­tralian zo­ol­o­gist, and his as­so­ci­ates to place a threat­ened label on B. parvus. A de­bate be­tween tourism econ­o­mists and wildlife con­ser­va­tion­ists soon de­vel­oped (Broome and Mansergh 1994). Since these de­bates, mea­sures have been taken to de­crease the amount of habi­tat frag­men­ta­tion and de­struc­tion by the ski in­dus­try. For the B. parvus habi­tats in es­tab­lished ski re­sorts, un­der­ground tun­nels with sim­u­lated B. parvus habi­tat sub­strate have been con­structed to aid in dis­per­sal be­tween in­tact habi­tat and ski re­sort habi­tat (Mansergh and Scotts 1992). These tun­nels have be­come re­spected at the ski re­sorts by tourists and gov­ern­ment of­fi­cials alike. Fu­ture man­age­ment plans to save B. parvus in­clude pro­tect­ing un­de­stroyed lands and buffer lands sur­round­ing the ski areas, con­tin­u­ing to de­vise tun­nel­ing sys­tems for al­ready af­fected B. parvus pop­u­la­tions, mon­i­tor­ing ef­fects of snow groom­ing on B. parvus habi­tats and pop­u­la­tions, and mak­ing the pub­lic more aware of the vul­ner­a­bil­ity of this an­i­mal (Broome and Mansergh 1994).

The pre­sent habi­tat of B. parvus is less than 10 square kilo­me­ters. The pre­sent pop­u­la­tion of B. parvus is no more than 2600 adults (Stra­han 1995).

• IUCN Red List

  Critically Endangered
  More information

Other Com­ments

The moun­tain pygmy pos­sum was dis­cov­ered as a fos­sil by Robert Broome in 1894. He named the species Bur­ramys parvus, mean­ing small rock mouse, al­though it is not a mouse at all (Broome and Mansergh 1994). Den­ti­tion stud­ies re­vealed a pla­giaula­coid pre­mo­lar, like that char­ac­ter­is­tic of the fam­ily Po­toroidae. From this ob­ser­va­tion, it was ques­tioned whether the pygmy pos­sum was ac­tu­ally a tiny kan­ga­roo (Ride 1970). For sev­enty years, B. parvus was con­sid­ered a fos­sil, until again found in a Vic­to­rian alps ski lodge in 1966 by ac­ci­dent (Ride 1970). An­other in­ter­est­ing as­pect of B. parvus life his­tory is hi­ber­na­tion. Bur­ramys parvus hi­ber­nates in the cold alps win­ter. It puts on large amounts of fat, which serves as en­ergy dur­ing the re­duced meta­bolic and body tem­per­a­ture state of tor­por. Dur­ing tor­por, B. parvus rolls it­self into a ball and tucks its tail around the body. Al­though en­er­get­i­cally costly to re­warm the body, B. parvus oc­ca­sion­ally arises dur­ing hi­ber­na­tion to feed on the seeds cached in its bur­row (Broome and Mansergh 1994). The hi­ber­na­tion pe­riod lasts for 6 months, from Feb­ru­ary through July.

Con­trib­u­tors

Jamie Ben­der (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

Broome, L. and Mansergh, I. 1994. The Moun­tain Pygmy Pos­sum of the Aus­tralian Alps. New South Wales Uni­ver­sity Press, New South Wales.

Lee, A. and Cock­burn, A. 1985. Evo­lu­tion­ary Ecol­ogy of Mar­su­pi­als. Cam­bridge Uni­ver­sity Press, Mel­bourne.

Mansergh, I., Bax­ter, B., Scotts, D., Brady T., and Jol­ley, D. 1990. Diet of the Moun­tain Pygmy Pos­sum, Bur­ramys parvus, and other small mam­mals in the alpine en­vi­ron­ment at Mt. Hig­gin­botham, Vic­to­ria. Aus­tralian Mam­mal­ogy 13:167-177.

Mansergh, I. and Scotts, D. 1992. Habi­tat con­ti­nu­ity and so­cial or­ga­ni­za­tion of the Moun­tain Pygmy Pos­sum re­stored by tun­nel. Jour­nal of Wildlife Man­age­ment 53: 701-707.

Mansergh, I. and Scotts, D. 1990. As­pects of the life his­tory and breed­ing bi­ol­ogy of the Moun­tain Pygmy-Pos­sum, Bur­ramys parvus, in alpine Vic­to­ria. Aus­tralian Mam­mal­ogy 13:179-191.

Menkhorst, P.W. 1995. Mam­mals of Vic­to­ria: dis­tri­b­u­tion, ecol­ogy, and con­ser­va­tion. Ox­ford Uni­ver­sity Press, Mel­bourne.

Ride, R.D.L. 1970. A Guide to the Na­tive Mam­mals of Aus­tralia. Ox­ford Uni­ver­sity Press, Mel­bourne. Smith, A.P. and Broome, L. 1992. The ef­fects of sea­son, sex and habi­tat on the diet of the Moun­tain Pygmy Pos­sum. Wildlife Re­search 19:755-58.

Stra­han, R. 1983. The Aus­tralian Mu­seum com­plete book of Aus­tralian Mam­mals: the Na­tional Pho­to­graphic Index of Aus­tralian Wildlife. Angus and Robert­son, Lon­don.

Stra­han, R. 1995. Mam­mals of Aus­tralia. Reed Books, Chatswood, New South Wales.

Wil­son and Reeder. 1997. http://​nmnhwww.​si.​edu/​gopher-menus/​MammalSpeciesoftheWorld.​html.​