Wombats (Vombatus and Lasiorhinus spp.) Fact Sheet: Behavior & Ecology

• Generally nocturnal - little activity during day
  • Typically emerge from burrow at sunset to graze for several hours (Wells 1989)
  • Summer - more active from midnight to early morning
  • Winter - more active from late afternoon to early evening
• Most of time in underground burrows (see Burrowing, below)
  • Common wombats - 2/3 time in burrow on average (Triggs 1996)
  • Northern hairy-nosed wombats - 2-6 h above ground per day (Johnson 1991)
  • Southern hairy-nosed wombats - 6+ h above ground per day (McIlroy 2008)
  • Sleep in burrow up to 16 h to conserve energy
  • May bask in sun at/near burrow entrance during cooler months

• Individual home range - small for an herbivore - variable across species and between individuals
  • Includes burrows, feeding places, rubbing posts, dust-bathing patches, etc.
  • Connected by network of paths
• Common wombat (Jackson 2003; McIlroy 2008; Triggs 1996)
  • Home range 2-82 ha (5-203 acres)
    • Size depends on distribution of burrows relative to feeding areas
    • Smaller core area used more intensively
• Northern hairy-nosed wombat (Johnson 1991)
• Home range around 25 ha (62 acres)
  • Estimated in study of 14 radio-collared wombats in the Epping Forest colony
  • Core areas (70% of activity) averaged 5.8 ha (14 acres)
• Southern hairy-nosed wombat
  • Home range about 1.3-7.8 ha (3-19 acres) (Finlayson et al. 2005; Walker 2006)
    • Extremely small compared to other herbivores in same environment
      • Western grey kangaroo (Macropus fuliginosus) has home range of 380 ha (939 acres) (Tyndale-Biscoe 2005)
    • Different individuals have overlapping ranges

• Wombats are the only large, burrowing, herbivorous mammal (Johnson 1998; Steele & Temple-Smith 1998; Triggs 1996)
  • A semi-fossorial (burrowing) lifestyle is a key characteristic of wombats (Shimmin et al. 2001-2002)
    • One of largest of all burrowing mammals, and the only large burrowing herbivore
    • Most large herbivores cope with low-energy diet by spending much of their time feeding over large ranges
      • Typically spend much of their time feeding over large ranges
    • Most large burrowing animals (e.g. aardvark, giant pangolin) live on energy-rich insect diets
    • Wombats unique - live on low-quality grazing diet but have small ranges and spend much of their time in burrows
      • Energy-conserving physiological and behavioral adaptations make this possible
• Benefits of burrowing (Woolnough & Steele 2001)
  • Behavioral regulation of internal temperature
    • External environment harsh - up to 35-40°C (95-104°F) in summer, to 0°C (32°F) or below at high elevations in winter
    • Wombats unable to internally regulate body temperature adequately in outside temperatures >25°C (77°F) (Jackson 2003)
    • Burrows have fewer temperature extremes than outside
  • Burrows used for behavioral regulation of water balance
    • Need to conserve water in arid environment
    • Burrows have higher humidity than outside
• Costs of burrowing (Shimmin et al. 2001-2002; Woolnough & Steele 2001)
  • Large investment of time and energy to construct burrows - increases with size of animal
    • In study of captive southern hairy-nosed wombats under controlled digging conditions, wombats excavating 10-15 cm (4-6 in) tunnel in 50 min consumed about 12,000 times as much energy as walking that distance (Shimmin et al. 2001-2002)
      • Based on this study, excavating a 10-m (33-ft) tunnel would take 80 hrs and consume more energy than walking 120 km (75 mi)
  • Limited space - reduced range size, reduced ability of individuals to disperse
  • Limited air circulation - low oxygen, high CO2
  • Limited movement
  • Sensory deprivation

• Unique digging style (Shimmin et al. 2001-2002; Triggs 1996)
  • Digs several strokes with one forefoot then switches sides
  • Backs up pushing loosened soil behind - deposits outside entrance, creating ramp
  • Lies on side scratching at roof/walls to enlarge
  • Bites off vegetation/roots in path (eats if edible)
  • Very fast diggers
    • A common wombat in the wild was observed to dig 1 m (3.3 ft) in 1 night, 6 m (20 ft) in 1 week (Triggs 1996)
    • In a controlled research study, captive southern hairy-nosed wombats excavated average of 20-30 kg (44-66 lb) dirt in 50 min, with one excavating 42 kg (93 lb) (Shimmin et al. 2001-2002)
• Burrow design and use (Jackson 2003; Matthews & Green 2012; Shimmin et al. 2001-2002; Steele & Temple-Smith 1998)
  • Burrow design differs between wombat species
    • Features in common
      • Generally elliptical in cross-section (width > height)
      • Maximum depth about 200 cm (79 in)
      • Variable length - 1.5-60 m (5-200 ft)
      • One or more chambers (sleeping; waiting areas)
  • Common wombat - loose arrangement of burrows
    • Individuals use about 10 single-entrance burrows
      • About 3 burrows get most use
    • Large nesting/sleeping chambers
      • Lined with twigs, leaves, bark, grasses, ferns
      • May assist temperature regulation in cool habitat
  • Northern hairy-nosed wombats - loose cluster of small warrens
    • Warrens: systems of branching, interconnecting burrows
    • Major warrens have 1-7 entrances connected by surface trails
    • Up to 10 warrens loosely clustered in a few hectares, surrounded by small single-entrance burrows
    • Burrows excavated horizontally into shoulder of sandy gully
      • Stabilized by tree roots
      • Above waterline in wet season
  • Southern hairy-nosed wombat - large, complex warrens shared by many individuals
    • Warrens often old, used by many generations
      • Maintained and extended - complexity increases with age
      • May include several burrows; burrows may branch with several entrances
    • Warrens show large range of complexity, size
      • 1-100 entrances per warren
      • Largest in 1 study had about 30 entrances, 100 m (330 ft) of tunneling (Shimmin et al. 2001-2002)
    • 10-20 warrens per colony
    • Small chambers occur frequently along tunnel - may be resting points or places to leave young
    • Individuals use multiple burrows and up to 10 warrens
      • Allows wombats to cover different parts of their home range over a number of nights
      • 1 study tracked 1 individual to 14 burrows (Matthews & Green 2012)
    • Individuals rarely share burrows, but several may share a warren

• Generally solitary outside of breeding season (Jackson 2003)
  • Common wombats (Triggs 1996)
    • Typically found alone, although use shared trails, rubbing posts, feeding places, burrows
    Southern hairy-nosed wombats
    • Somewhat more gregarious - may share a warren but rarely a burrow (Taggart 2008)
    • Closely related males show preferential burrow- and warren-sharing (Walker 2008)
• Minimal social contacts with other wombats (Triggs 1996)
  • Common wombats can communicate with and recognize a colony member
  • 2-3 individuals may feed within 30-40 m (10-13 ft) but generally don't approach closer than about 3 m (10 ft)
  • Several may seek refuge from predators or severe weather together in nearest burrow

• Vocalization (Jackson 2003; Triggs 1996)
  • Stress
    • May scream loudly and gnash teeth
  • Separation of mother and young
    • Young - repeated soft "huh huh" when mother out of sight
    • Mother - "huh huh" in reply
  • Invasion of personal territory warning
    • At close approach of another individual
    • Begins with low guttural growl
    • Followed by repeated high, loud, rasping hiss - may rise to level of screech
  • More aggressive warning - possible prelude to fight
    • May be initiated when 1 wombat meets another, or hears/smells another far away
    • Initiated by 1 individual with series of vocalizations - flat "chicker chicker" and rasping "chur"
    • Answered by the other, followed by series of calls and answers
    • May continue for some time, ending either in non-confrontational passage or chase initiated by either individual
  • During fight
    • May produce throaty snorts and nasal squeals (common wombat)
• Posturing (Triggs 1996)
  • Hostile gestures may occur before fight
    • Individual stands, or sits with front feet wide apart and body humped to appear larger
    • Head swings side-to-side while teeth mimic biting and body shivers
• Olfactory cues (Steele & Temple-Smith 1998; Triggs 1996)
  • Scent marking
    • Cloacal scent glands secrete brownish liquid containing pheromones (hormones used for communication)
    • May deliberately leave scent trail by depositing a few drops on ground or objects
      • In path as individual enters burrow or moves around range
      • On top of scats
  • Fecal deposits
    • Large volumes - common wombats average 80-100 scats per night
    • Scattered across territory
      • Often on trails or entrances to occupied burrows
      • Often on new or altered objects in territory
  • Scratch marks
    • Southern hairy-nosed wombats leave scratch sites on tracks
    • Typically 10-20 cm (4-8 in) in fresh earth

• Highly aggressive behavior is normal (Jackson 2003)
  • After emerging from pouch (about 9 mo old) - become aggressive
  • Post-weaning (about 18 mo old) - become very aggressive
  • Female approaching estrus - increasingly aggressive towards young
    • Severe biting and chasing (Böer 1998)
  • May dispute use of a burrow
  • May defend favorite feeding area (Triggs 1996)
  • During capture, may bite, scratch, or attack
• Confrontations may involve warning vocalizations, hostile posturing (Triggs 1996)
  • May end in chase sequence
    • Pursuer and pursued may change roles
• Fighting is rare
  • May involve bites to face, ears, rump, flanks (Wells 1989)
  • Head-on conflicts occur in burrows or entrances when individual in burrow resists entry of another (Triggs 1996)

Territorial Behavior

• Territorial with respect to feeding areas (Jackson 2003)
• Individuals may dispute use of a burrow (Triggs 1996)

Play

• Young wombats - after leaving pouch, common wombats show bursts of vigorous play (Triggs 1996)
  • Play initiation: stand completely still on stiff front legs, then jerk head/shoulders up (may lift front feet off ground)
  • Common play behaviors
    • Toss head from side to side
    • Jump in air with all four feet off ground
    • Roll over on side
    • Gallop off then comes to sudden stop, reverse direction, race back to mother, veer off just before collision
    • Lie on stomach, throw head back and swing it side-to-side with lips drawn back in "grin"
    • Run up slope and roll down on side
• Captive wombats - play behaviors observed in southern hairy-nosed wombats in zoo (Moeller 1990)
  • Biting, tossing, chasing plastic pail
• Standing on hind legs whipping towel side-to-side with head tosses
• Leaping into air with all legs off ground, chasing tail in circles, rolling on ground

• Plantigrade - walk on whole sole of foot
  • Common in animals that walk more than run (humans, bears, etc.)
  • Video - northern hairy-nosed wombat walking (front and rear views) (DEHP 2012)
• Generally walk but can move rapidly
  • Slowly over short distances, rapidly across longer distances; can gallop to escape aggression/danger (Triggs 1996)
  • Southern hairy-nosed wombat can move at speeds >40 km/h (25 mph) (Taggart & Temple-Smith 2008)

• Predators (Jones & Barmuta 1998; Menkhorst & Knight 2011; Triggs 1996)
  • Humans
  • Dingoes (Canis lupus)
    • Introduced 3,500-4,000 years ago by Asian seafarers (Corbett 2008)
  • Wild dogs (feral dog-dingo hybrids)
  • Red foxes (Vulpes vulpes)
    • Introduced in 1860s and 1870s by European settlers for sporting purposes (Catling & Coman 2008)
  • Few natural predators - in Tasmania:
    • Tasmanian devils (Sarcophilus harrisii)
  • To a lesser extent, male spotted-tailed quolls (Dasyurus maculatus)
• Defense (Triggs 1996)
  • Crouches in burrow entrance - presents broad, reinforced rump to attacker
    • Responds to touch with powerful thrust against burrow roof/wall - can crush head of attacker
  • In open - can deliver crushing bite, stab with lower incisors

The muscular forelegs of wombats are adept at excavating burrows.

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.

Finlayson et al. (2005)
Horsup & Johnson (2008)
Jackson (2003)
Johnson (1991)
Johnson (1998)
Matthews & Green (2012)
McIlroy (2008)
Shimmin et al. (2001-2002)
Steele & Temple-Smith (1998)
Taggart & Temple-Smith (2008)
Triggs (1996)
Tyndale-Biscoe (2005)
Walker (2006)
Wells (1989)
Woolnough & Steele (2001)