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Western Gray Kangaroo (Macropus fuliginosus) Fact Sheet: Behavior & Ecology

Western Gray Kangaroo (Macropus fuliginosus)

Activity Cycle

Daily activity patterns

  • Daily activity strongly influenced by changes in temperature and day length, as well as humidity and wind (which has a cooling benefit) (Arnold et al. 1988)
    • Weather conditions influence grazing, resting postures (crouching, standing, lying), and shade-seeking behaviors
  • In hot weather, rest in shallow hip-holes made in the shade (Eldridge and Coulson 2015)
  • Generally active at dawn and dusk (crepuscular) and sometimes at night (nocturnal), but activity patterns variable (Eldridge and Coulson 2015)
    • Patterns seem to vary with season, weather, location, and food availability (Dawson 2013; Eldridge and Coulson 2015)
    • For some individuals, habitat areas used during the day vs. night overlap very little; for other individuals, large amount of overlap
      • For instance, may shift from using shaded, shrub woodland during sunny daytime hours to open woodland/farmland during the night (Arnold et al. 1992)
  • Majority of non-resting time is spent feeding, particularly in winter (Dawson 2013)
    • Forage 6-10 hours per day, often around dawn and dusk (Priddel 1986)
      • Begin foraging later in the evening on hot days (Arnold et al. 1988)
    • Spend about 20% less time foraging during the summer (may be due to shorter nights and high daytime temperatures)
      • Reduces water loss because food held in gut longer and feces are drier
    • Males often feed for about an hour longer per day compared to females; may need to feed longer to take in more energy to support their larger bodies

Movements and dispersal

Home range

  • Most adults are resident, have relatively small home ranges, and infrequently disperse far (Priddel et al. 1988a; Eldridge and Coulson 2015)
    • Priddel et al. (1988b) found that more than 90% of western gray kangaroos moved a distance of less than 6 km (3.7 mi) and 99% moved less than 20 km (12.4 mi)
  • Strong site fidelity to their home ranges, even over multiple years (Arnold et al. 1992; Dawson 2013)
    • Exception: Young, mature males (about 5 years old, 45 kg/100 lb) may move a short distance (1 km, or 0.6 mi) to establish new home ranges
    • Exception: Females leaving their natal area (Neaves et al. 2013)
  • Boundaries of home range somewhat fixed (Dawson 2013)
    • May gradually ‘drift’ over weeks or months, especially in open country
  • A kangaroo’s home range may shift, expand, or contract with changes to food supply (typically caused by spatial differences in rainfall) (Pople et al. 2007; Dawson 2013), although not all studies have found evidence of this (e.g., Priddel et al. 1988a)
  • Average home range sizes larger in semi-arid environments compared to pasture lands adjacent to wooded cover (Eldridge and Coulson 2015)
  • Home ranges of male and females overlap extensively, with those of older males generally being larger (Arnold et al. 1992; Eldridge and Coulson 2015)
    • In one study, large males had nighttime home ‘activity’ ranges twice the size of females; home ranges of young males were comparable in size to females (Dawson 2013)

Longer-range movements

  • Though uncommon, some individuals do disperse and move far (Dawson 2013, except as noted)
    • About 6% of individuals reported to move farther than 10 km (6.2 mi) away
    • Long movements of up to 85 km (53 mi) documented (Priddel et al. 1988b)
    • Some individuals make long distance movements and then return to areas they previously used
  • Gene flow over distances of greater than 100 km (62 mi) is common (Eldridge and Coulson 2015)
    • Maintains connectivity among populations (Neaves et al. 2013)
    • Some genetic evidence suggests males disperse quite far (Neaves et al. 2013)

Barriers to movement (Chachelle et al. 2016)

  • Roadways and railways divide kangaroo habitat into smaller areas
  • When kangaroos cross roadways to reach grazing areas, potential for injury/death to motorists and kangaroos
  • Construction of large freeway underpasses allows western gray kangaroos to move between habitat fragments without risk to motorists and kangaroos (unlike fencing off areas); not shown to affect home range size

Responses to danger

  • Avoid or vacate habitat areas where potential predators are detected (Parsons et al. 2007; Mella et al. 2014)

Social Behavior

Kangaroo “groups” have loose, but structured membership

  • Gray kangaroos are the most social macropods (Staker 2006)
  • Complex group hierarchies: “Groups” and “subgroups” are the fundamental units of social structure in a kangaroo population (Dawson 2013)
  • Membership in groups is partially open, with considerable movement of individuals in and out of groups (Johnson 1983; MacFarlane and Coulson 2009; Eldridge and Coulson 2015)
    • Some non-random associations reported, but no scientific basis for so-called "kangaroo mobs"
  • Adult females with young and juveniles form the core of groups (Dawson 2013)
    • A few adult males may be in contact with adult female groups
  • Associations among mature males are loose and not long-lasting (Dawson 2013)
    • In some populations, males seem to seek out the company of other males (results in male-female segregation) (MacFarlane and Coulson 2009)
      • May provide opportunities for males to size up rivals or practice fighting (Johnson 1983; MacFarlane and Coulson 2009)
    • Johnson (1983) observed that, during winter, western gray kangaroos formed larger all-male groups and were more gregarious; during spring and summer, males interacted with females
  • Average group size: about 3 individuals (range 1-16) (Arnold et al. 1990; Dawson 2013)
    • Usually found in small groups of 3 to 6 individuals (Dawson 2013)
    • Large aggregations may form around food, water, and shade (Dawson 2013)
  • Group size tends to be larger in areas of higher population density and in more open habitats (Eldridge and Coulson 2015)
    • Members can better share the duties of scanning for predators and spend more time feeding; may also result in competition and resource depletion (Dawson 2013)
  • Dominance hierarchies (Dawson 2013)
    • Size and age largely determine dominance ranking in captivity and in the wild
    • Large and medium males dominant over females
    • Reproductive condition may factor into dominance interactions among females
  • Western gray and eastern gray kangaroos sometimes form mixed-species groups (Dawson 2013)
    • Western gray kangaroos will move farther from cover in order to feed
    • Rarely seen in the tall eucalyptus woodland favored by eastern gray kangaroos

Seasonal changes in behavior

  • Sexual segregation (males and females do not interact) during non-breeding season (winter) (Coulson et al. 2006; Eldridge and Coulson 2015)
  • During the breeding season, large, adult males move around their home range, surveying and assessing the reproductive state of females (Eldridge and Coulson 2015)

Non-aggressive behaviors (Dawson 2013, except as noted)

  • Low levels of aggression among kangaroos, except between males during the breeding season
  • Touch
    • Mutual nose touching or touching on the body; often used when an individual joins a group
    • Licking lips or part of another individual’s body (among group members)
    • Nuzzling the pouch of a female
  • Grooming
    • Head, ears, and back frequently nibbled or raked with paws (Coulson 1997)
    • Group members may help each other groom hard-to-reach places, although self-grooming also often reported (also, McCullough and McCullough 2000)
  • Social play
    • Mostly occurs between young males, and mothers and offspring (Sarah Garnick, personal communication, 2017)
  • Common interactions
    • Males approaching females (non-sexual)
    • Mothers and young (e.g., grooming, nursing)

Communication

Visual communication

  • Individuals in foraging groups monitor one other (Eldridge and Coulson 2015)
  • Body postures alert other kangaroos to danger (alarm behavior) (McCullough and McCullough 2000)
    • Rise up on hind legs and tail to look for the source of disturbance
  • Males display to opponents

Vocalizations and auditory communication

  • ‘Cough’ vocalization (Dawson 2013)
    • Used to signal dominance and gain access to shade/food
  •  ‘Ha’ vocalization (Dawson 2013)
    • Produced while pushing, when a kangaroos attempts to displace an opponent
  • Clicking call (observed in captivity) (Coulson 1997)
    • Used by females to call a joey to return to the pouch
  • Young may give short, ‘bleating’ or ‘hissing’ calls when they lose contact with their mother (Coulson 1997)
  • Produce loud ‘thumps’ by jumping in the air and then bringing feet down hard on the ground (Eldridge and Coulson 2015)
    • May communicate to a potential predator that it has been detected
    • Other kangaroos may also be alerted to the predator’s presence

Olfactory communication (Eldridge and Coulson 2015)

  • Thought to play an important role, but is poorly understood
  • Odors of the mouth and nose may be involved in identification of individuals or social classes
  • Glands of male western gray kangaroos secrete an oily substance which has a strong odor (“smells like curry”)
    • Mark vegetation, and during courtship, certain body parts of females (e.g., head)
  • Olfaction also helps males assess the reproductive state of females
  • Smells produced by mother kangaroos may help guide newborns to her pouch; scientific studies needed

Tactile communication

  • Only plays a minor role in communication among kangaroos and their relatives, except during grooming, fighting, courtship/mating, and between mothers and their young (Eldridge and Coulson 2015)
  • Joeys often lick mothers and surrogate mothers in captivity (Staker 2006)
    • Licking strengthens joey-mother bond
  • See Non-aggressive Behaviors
  • See Agonistic Behavior and Defense

Agonistic Behavior and Defense

Dominance-submission interactions may be subtle (Coulson 1997; Dawson 2013)

  • Aggression in kangaroos often initiated to gain access to shade or feeding areas
  • Submission may be indicated by:
    • A submissive individual moving away and/or coughing
    • Slight changes in body posture
    • Changes in head or ear position
  • Dominant individuals supplant submissive individuals much more often than encounters escalate to fights
  • Dominant females able to displace females and small males

Aggressive acts (Dawson 2013, and as noted)

  • Threat postures
    • Upright postures, including standing on tip-toe while using tail for balance
    • Stiff-legged walking
      • Observed in males, particularly when a rival will neither fight nor retreat
      • Dominant individual circles rival in this stance
    • Lips pulled back to reveal front teeth (Coulson 1997)
    • Males pull at vegetation or clump vegetation into their chest (Staker 2006)
      • Display thought to have originated from scent marking behavior, but now has strong, visual elements (e.g., chest scratching, fur raking) (Dawson 2013; Eldridge and Coulson 2015)
  • Vocalizations
    • ‘Cough’ (Coulson 1997)
      • Loud and pronounced
  • Quivering (Coulson 1997)
  • Pushing and chasing
    • Individuals grasped around their middle and pushed away
    • ‘Ha’ vocalization may be made during pushing
    • Aggressor may hit an opponent with its forepaw and continue chasing and hitting as the opponent flees
  • Fights
    • Used to establish dominance hierarchies
    • May fight for access to drinking water, resting sites, or by males seeking access to females in estrous
    • Rise high on hind legs and use sharp front claws to slash at opponent and sharp teeth to bite opponent (McCullough and McCullough 2000)
    • Ritualized fighting or ‘boxing’ exhibited by males
      • May be preceded by intense scratching/grooming or high standing postures
      • McCullough and McCullough (2000) report more clawing/slashing and less wrestling/kicking observed among western gray kangaroos compared to other species
      • Groom and scratch themselves during breaks in the fights
      • Winner decided when one animal retreats; the stronger individual (also typically the one who initiates the fight) usually wins
    • Young kangaroos thought to learn these behaviors at an early age; short ‘play fights’ between mothers and young or two young males

Territorial Behavior

Home ranges limited by certain factors

 

  • Not strongly territorial (Sarah Garnick, personal communication, 2017)
  • Dawson (2013) states: “For kangaroos, home ranges are not ‘territories’ because they seem not to be defended; however, subtle pressures (e.g. kinship, size and sex) seem to limit overlap in home ranges at times.”
  • Also see Movements and Dispersal

 

Other Behaviors

Licking the lips of another kangaroo

  • Young observed to lick their mother’s lips, apparently to collect saliva (Dawson 2013)
    • By this action, microorganisms which help in digestion of vegetation may pass from the mother to soon-to-be-weaned young

Play behavior

  • Usually only between mothers and their young (Dawson 2013)
  • Play fighting observed in other species of kangaroos, such as eastern gray kangaroo and antilopine kangaroos (Dawson 2013)

Response to flying insects

  • When flies or mosquitoes are abundant, kangaroos frequently shake their heads and flap their ears (McCullough and McCullough 2000)

Ecological Role

Varied impacts

  • As highly mobile grazers, kangaroos fill many important roles related to nutrient cycling, habitat structuring, etc. (Sarah Garnick, personal communication, 2017)

Important disperser of seeds

  • Disperse small and medium-sized seeds of native and non-native plants (especially herbaceous plants); more frequently disperse non-native species (Calvino-Cancela 2011)
  • Western gray kangaroos, along with emus (Dromaius novaehollandia) and European rabbits (Oryctolagus cuniculus), are the most important seed dispersers in southwestern Australia (Calvino-Cancela 2011)

Interspecies Interactions

Interactions with other kangaroos

  • Range overlap with three other large kangaroo species (eastern gray kangaroo, red kangaroo, euro/common wallaroo) in some parts of its range (Munn et al. 2014), as well as many smaller macropods (e.g., wallabies) (Sarah Garnick, personal communication, 2017)
  • May feed with eastern gray kangaroos in open grassland, but limited habitat overlap (western gray kangaroos use more scrub with heath and shrubs, whereas eastern gray kangaroos tend to use taller woodlands with grasses and herbs) (Dawson 2013)

Interactions with livestock and agriculture

  • Edge of the western gray kangaroo’s arid range overlaps with merino sheep (bred for wool) (Munn et al. 2014)
  • Kangaroos and merino sheep eat some of the same plants, but little evidence exists to suggest competition (red kangaroos) (Dawson 2013)
    • Older male and small female kangaroos most affected by sheep during dry times of year
    • Munn et al. (2014) report no observations of agonistic behaviors between sheep and western gray kangaroos; sheep ate mainly tree browse whereas kangaroos ate grasses
  • Some economic losses for landholders (Dawson 2013)
    • Impacts
      • Damage to cereal crops
      • Competition between kangaroos and livestock for food; this is the main concern of most farmers
      • Kangaroos drinking water provided for livestock
    • Estimates of perceived loss reported, but actual levels of loss unknown
    • See Commercial Hunting

Locomotion

Hopping

  • Kangaroos achieve continuous movement through the bipedal hop (called “saltatory locomotion”) (Dawson 2013)
  • Hopping uncommon among vertebrates (Dawson 2013)
    • Besides kangaroos and their relatives, only frogs and some small mammals (e.g., desert rodents) use this form of locomotion
    • Hopping is also rare among mammals, especially large mammals (Dawson 2013)
      • Special to kangaroos, their macropod relatives, four families of small rodents, and the kultarr (Antechinomys laniger)
      • Kangaroos are the only vertebrate larger than 5 kg (11 lb) that hops; none known from fossil evidence, either (Dawson 2013)
  • Hopping saves energy when moving at higher speed (beginning at 6-7 kph, or 3.7-4.3 mph, but most efficient above 12 kph, or 7.5 mph) (Dawson 2013)
    • Advantageous for sustaining speed
    • At high speed, a kangaroo uses only half the energy of a quadrupedal mammal
  • Take longer strides to move faster (S. Garnick, personal communication, 2017)
  • Stride frequency also increases at higher speeds (above 35-40 kph/22-25 mph) (Dawson 2013)
  • Walking or hopping at slow speeds has a relatively high energy use (Dawson 2013)
  • If have enough time and space to get moving, kangaroos can out-speed predators, such as dingoes (Dawson 2013)
  • Recorded speeds
    • Highest speeds reliably observed: about 55-60 kph (34-37 mph) (red and gray kangaroos similar) (Dawson 2013)
    • Preferred speed of the red kangaroo: about 20 kph (12.4 mph) (Dawson 2013)

Walking

  • Kangaroos use four limbs and their tail for propulsion (termed “pentapedal locomotion”) (Dawson 2013)
    • Front legs and tail support the kangaroo’s body weight, as the two hind limbs are brought forward (Dawson et al. 2014)
  • An energetically costly gait (Dawson 2013)
    • Uses double the energy compared to a walking dog
  • Walk mostly at slow speeds, up to 6 kph (3.7 mph); rarely walk fast (Dawson 2013)
  • Quickly transition from slow walking (e.g., during feeding or while relaxing) to rapid hopping (e.g., to flee danger or otherwise move far) (Dawson 2013)
  • Body structures are limiting; tradeoff between efficiency at high speeds and inefficiency at slow speeds, especially for large-bodied animals (Dawson 2013)
  • Contrary to popular belief, kangaroos can walk backwards (Staker 2006)

Swimming

  • Good swimmers (Dawson 2013), but only swim if they have to; is not typical behavior (Sarah Garnick, personal communication, 2017)
  • Alternate hind legs as they “doggie paddle” (Dawson 2013)

Beat the Heat

Western gray kangaroo resting

In hot weather, western gray kangaroos spend much of their time resting.

Image location: Toronto Zoo.

Image credit: Ber'Zophus via Wikimedia Commons; CC Attribution ShareAlike 2.5 Generic license. Public domain.

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