Sugar Glider (Petaurus breviceps) Fact Sheet: Physical Characteristics

Body measurements

Data sources: Suckling (1984), Lindenmayer (2002), Jackson (2012)

Body

• One of the smallest lesser gliders (genus Petaurus) (Jackson 2015a)
• Body size highly variable (Jackson 2015a)
  • Increases with latitude (i.e., larger in colder regions farther south) (Quin et al. 1996)
• Skin membrane for gliding (patagium) unites front and hind limbs (Endo et al. 1998; Jackson 2015b; Nowak 2018b, except as noted)
  • Two layers of connective tissue with muscles and nerves
  • Extends from wrists to ankles (Suckling 2008)
  • Folds along flanks when not gliding
• Also see “Gliding” in Locomotion

Coloration

• Variable throughout range (Jackson 2015a)
• Upperparts gray (Nowak 2018a)
  • May have blue or brown infusion (Suckling 2008)
  • Single black stripe from crown to rump (Jackson 2015b)
• Underparts pale cream to medium gray (Jackson 2015a)
• Tail dark gray (Fleay 1947; Jackson 2015a)
  • In 20 to 50% of individuals, transitions to black or white near tip

Pelage

• Fur fine and silky (Smith 1973; Nowak 2018a)
  • Increases lift and aids gliding (Nachtigall 1979)
• Northern subspecies have shorter fur than southeastern subspecies (P. b. breviceps) (Jackson 2015a)
• Also see “Tail,” below

Head and teeth

• Face
  • Short (Jackson 2015a)
  • Blunt (Jackson 2015a)
  • Sensory hairs (i.e., whiskers) on nose and face (McKay 1989)
    • Aid movement and foraging at night
• Eyes
  • Large (McKay 1989)
  • Protruding (McKay 1989)
  • Tapetum lucidum (light reflecting layer of pigment) (McKay 1989)
    • Aids vision in low-light conditions
• Ears
  • Fairly large (Smith 1973)
  • Oval-shaped (Jackson 2015a)
  • Thin (McKay 1989)
  • No fur (Jackson 2015a)
• Lower incisors long and curved (Smith 1973)
  • Chew into tree bark (Dierenfeld 2009)
  • Also enlarge insect-bored holes to access tree gums (Dierenfeld 2009)
• Large scent gland on head of adult male (Goldingay 2010)

Feet and limbs

• Forefeet
  • Elongated fourth and fifth digits with long claws (Fleay 1947; Smith 1973; Lindenmayer 2002; Dierenfeld 2009)
    • Assist landing and clinging to trees after a glide
    • Fourth digit used to extract insects from under bark and tree crevices
  •  “Winglets” (Jackson 2015b)
    • Fringe of fur on fifth digit of forefeet
    • Increases stability and reduces drag
• Hindfeet (Jackson 2015b)
  • Rotate 180°
    • Able to climb down tree trunks head first
  • Big toe opposable and clawless
    • Provides added grip while climbing
  • Second and third digits fused together (syndactyly)
• Soles of feet
  • Pads have fine striations for added grip (Smith 1973)
• Claws (Jackson 2015b)
  • Sharp
    • Used for climbing

Pouch

• Extends onto female’s flanks (Smith 1973)
• Usually contains 4 teats (Jackson 2015b)
• Two pouch areas (McKay 1989)
  • Two young most typical
• Brown secretion produced when young are in the pouch (Smith 1973)
  • Function undescribed

Tail

• Long (Ride 1970)
  • Used for balance while climbing
• Length of fur similar on all sides of tail (Jackson 2015a)
  • Less dense than in larger-bodied lesser glider species (Jackson 2000b)
• Moderately prehensile (Johnson and Hemsley 2008; Jackson 2015b)

Body size

• Male larger than female (Quin 1995)

Scent glands

• Adult males have scent gland patch on forehead (Smith 1973)
• Also see “Olfactory communication” in Communication

Similar-looking species

• Squirrel glider, Petaurus norfolcensis (Lindenmayer 2002; Suckling 2008)
  • Squirrel glider is larger, has denser fur on tail, and makes different calls than sugar glider (Lindenmayer 2002; Sharpe and Goldingay 2009)

Metabolism

• Low metabolism (Dierenfeld and Whitehouse-Tedd 2018)
  • Adaptation for digesting complex sugars (e.g., plant gum)
• Rely on body fat reserves during winter, when food is less available (Holloway and Geiser 2001a)

Thermoregulation

• Tolerate a wide range of temperatures (Holloway and Geiser 2001b; Suckling 2008)
  • Typical body temperature while resting: about 36.3°C (97.3°F) (Holloway and Geiser 2001b)
• Prevention of overheating
  • Few sweat glands (Johnson and Hemsley 2008)
  • Lay on side or sit upright with limbs extended to dissipate heat (Smith 1973; Fleming 1980)
  • Spread saliva on forelimbs (Fleming 1980)
    • Facilitates dissipation of heat from blood vessels near skin surface
  • Drink small amounts of water (Smith 1973)
• Responses to cold
  • Group huddling
    • In nest, huddle together and share body warmth (Suckling 2008; Nowack and Geiser 2016)
      • Save energy
    • Young less than 100 days old mainly rely on body heat of adults (Holloway and Geiser 2000)
      • Also see “Newborn” in Life Stages
  • Torpor
    • During torpor, body temperature and metabolism reduced to conserve energy (Lindenmayer 2002)
      • Body temperature can fall to below 20°C (68°F) (Fleming 1980; Henry and Suckling 1984)
    • Usually occurs during daytime hours (rest period)
    • Adopt a curled posture, with furred tail covering feet and head (Fleming 1980)
    • Used by sugar gliders during extreme circumstances, not for routine energy savings (Johnson 2011)
      • Often enter short-term torpor (2 to 23 hours at a time) on cold or rainy nights, when little-to-no foraging opportunities (Körtner and Geiser 2000; Geiser et al. 2007; Jackson 2012; Jackson 2015b; Nowak 2018a, and as noted)
      • Deep torpor may also aid survival of severe storms (Nowack et al. 2015)
        • Energy savings of up to 67% (Nowack et al. 2015)
    • Most frequent late June to mid-August (austral winter)
      • Range: May to October

Because its hindfeet rotate 180°, the sugar glider can easily climb down trees and land after long glides.

Climbing is further aided by curved claws and special foot pads.

Also note in this photo how the skin that extends from the sugar glider's wrists to its ankles folds along the animal's sides when not gliding.

Image credit: © David Cook Wildlife Photography at Flickr. CC BY-NC 2.0; some rights reserved.