Kangaroos

roo.gif (957 bytes) Aliases roo.gif (957 bytes) Feeding roo.gif (957 bytes) Reproduction
roo.gif (957 bytes) Appearance roo.gif (957 bytes) Hopping roo.gif (957 bytes) Social System
roo.gif (957 bytes) Behaviours roo.gif (957 bytes) Mortality roo.gif (957 bytes) Status
roo.gif (957 bytes) Distribution
The sources of this information are provided under Resources

Aliases

Taxonomic classification
Superfamily Macropodoidea big footed
62 species in Australia & Papua New Guinea
size 1 kg - 90 kg
Family       Macroprodinae kangaroos and wallabies
Genus         Macropus kangaroos
six largest species of the family

Relationships among Kangaroos

Genus

Macropus

Kangaroos share:

  1. large size

  2. grazers
    - specialised teeth for cropping grass
    - complex forestomachs for the breakdown of plant fibre by fermentation

Species rufus fuliginosus giganteus antilopinus robustus bernadus
Common Names Red Kangaroo,
Marloo. Blue-flier (female)
Western Grey, black-faced kangaroo, sooty kangaroo, mallee kangaroo, stinker Eastern Grey, forester, scrubber, Great Grey Antilopine Kangaroo Common Wallaroo, Euro, briggada Black Wallaroo
Grouping Red Kangaroo Grey Kangaroos Antilopine Kangaroo

Wallaroo / Euro


Appearance

Species males females
  Height* Weigh Height* Weight
Red Kangaroo 1.8 m 90 kg 1.25 m 35 kg
Grey Kangaroos 1.6 m 70 kg 1.2 m 35 kg
Antilopine Kangaroo 1.5 m 49 kg 1.0 m 20 kg
Euro 1.6 m 58 kg 1.2 m 25 kg
Black Wallaroo 1.0 m 22 kg 0.8 m 13 kg
*  Height is measured when sitting up on their haunches.

MUZZLE DIFFERENCES
Red Kangaroo black and white patch at side of muzzle; the tip of the nose is naked and sharply outlined
Grey Kangaroos muzzle covered by fine hair; only the margins of the nostrils are bare black skin
Euro - Wallaroo nose is completely naked

Behaviours

Social interaction

roo.gif (957 bytes) these are actions that promote the unity of a group; don't include either displays of aggression or reproductive behaviour

Between group members:

roo.gif (957 bytes) mutual nose touching and sniffing, touching the lips of another, other touching and sniffing, grooming others, nuzzling a female's pouch
roo.gif (957 bytes) submissive behaviour - one animal, often smaller, holds its body close to the ground and its head may quiver
roo.gif (957 bytes) play-fighting among young, subadults, or mother and young - two animals involved grasp each other around the neck, touching forepaws and kicking

Mother and offspring:

roo.gif (957 bytes) mother grooms a young at foot while it is suckling or just after
roo.gif (957 bytes) young nuzzles its mother's pouch either to get in or to suckle or for reassurance the young may put its head into the pouch for a few seconds
roo.gif (957 bytes) young licks its mother's lips for several minutes, apparently collecting saliva; it is thought that this may result in the passage from mother to young of the digestive micro-organisms required for the fermentation of vegetation for nutrition
roo.gif (957 bytes) play-fighting

Aggression

roo.gif (957 bytes) fights ('boxing') between large males are rare
roo.gif (957 bytes) most fights are one-sided and end quickly; the challenged individual usually moves away
roo.gif (957 bytes) a submissive 'cough'/cluck is heard in eastern greys, wallaroos, euros but not in reds
roo.gif (957 bytes) threat displays indicate an intention to act aggressively; these include upright posture, stiff-legged walking, pulling on grass or bushes

Distribution

roo.gif (957 bytes)  Between them, the kangaroos range over most of Australia.
roo.gif (957 bytes)  In some areas there may be only one species while in other places several species occur.

Species Habitat preference
Red Kangaroo
  • arid and semi-arid regions;
  • most of the vegetated habitats - grasslands, shrublands, mulga
Western Grey Kangaroo
  • dry regions of the inland (lower half of the continent) and Western Australia
Eastern Grey Kangaroo
  • eastern third of the continent;
  • wide variety of habitats - high mountain forests, semi-arid ranglands;
  • only kangaroo found in Tasmania
Antilopine Kangaroo
  • monsoonal region of north Australia;
  • grassy, eucalypt woodlands
Euro group (4 subspp)
  • most widespread of the kangaroos;
  • most of the continent except the southern edge;
  • rough, hilly country
Black Wallaroo
  • central and western Arnhem Land in the Northern Territory;
  • woodlands, shrub cover, monsoonal forest

Feeding

roo.gif (957 bytes) reds and greys may feed in large mobs - size depends on the quality of food
roo.gif (957 bytes) most active at dawn and dusk; relatively inactive in middle of both day and night
roo.gif (957 bytes) time spent grazing varies seasonally between 7 and 14 hours
roo.gif (957 bytes) rest during the day in the shade of woodland; move onto grasslands to feed
roo.gif (957 bytes) eat a variety of plants but mainly grasses

Hopping

roo.gif (957 bytes) kangaroos are unique in being the only large animals that use hopping for locomotion
roo.gif (957 bytes) they walk at slow speeds and start hopping as speed increases

Energetics of hopping

roo.gif (957 bytes) when hopping starts its costs are high
roo.gif (957 bytes) as speed increases, the energy costs change little which means that a kangaroo hopping at a moderate speed (>15 km/hr) uses less energy than a similarly-sized animal that is running
roo.gif (957 bytes) for red kangaroos, the most comfortable speed is 20-25 km/hr
roo.gif (957 bytes) as speed increases up to about 40 km/hr, the hopping rate remains constant but the length of the hop increases
roo.gif (957 bytes) although red kangaroos can hop at speed of 65-70 km/hr for short distances, at these speeds the hopping rate increases as well as the hop length
roo.gif (957 bytes) while hopping has benefits in energy expenditure at high speed, at low speeds (below 6 km/hr) they have an awkward walk using their hind legs with the tail providing additional support for the front legs, and this is both clumsy and energetically expensive

CAUSES OF MORTALITY

Lack of Nutrition

particularly in young animals that don't have body reserves
Predation dingoes, eagles, foxes, humans
Disease filarioid nematode worm, Pelecitus roemeri found in the connective tissue; lumpy jaw caused by bacterium Fusobacterium necrophorum *
Environmental stress drought, flooding, severe wet and cold weather
* the incidence of mortality by disease vectors usually involves the interrelationship of some of the other factors listed

General

roo.gif (957 bytes) reds, euros, wallaroos - breed continuously under good conditions; greys are usually seasonal breeders
roo.gif (957 bytes) marsupial reproduction depends on lactation to nourish the poorly developed young; consequently, female marsupials have a greater investment in the care of their young
roo.gif (957 bytes) females coming into oestrus extend their area of activity to attract the largest male in that area; so, a large male will be able to mate with more females
roo.gif (957 bytes) there are indications that a female (of some species) may invest less in male offspring in years when conditions are poor and that this explains the increased male mortality of young males; the reasoning behind this is that to be a successful breeder a male needs to be large and males raised in poor seasons will never become the dominant male, whereas a female produced during a poor season will still breed and pass on her mother's genes

Gestation and birth

roo.gif (957 bytes) kangaroos have a relatively long gestation period compared to other marsupials ranging from about 31-36 days
roo.gif (957 bytes) exhibit embryonic diapause - a viable embryo is carried in the uterus with its development arrested at an early stage (except the Western Grey); development is recommenced after final pouch exit by the previous young
roo.gif (957 bytes) mother assists the newly-born into the pouch through pouch cleaning and birth posture (characteristic for each species); in reds, the female brings her tail forward between her hind legs and leans back against a tree while antilopines don't require back support and greys don't bring the tail forward; the newborn are visible for about three minutes before disappearing into the pouch

Lactation

roo.gif (957 bytes) in the euro, wallaroos, and red the young is continuously attached to the nipple until 120-130 days
roo.gif (957 bytes) composition of the milk is tailored to the requirements of the developing young e.g. around the time of hair formation, there is an increase in sulphur-containing amino acids (hair has a high content of sulphur-containing proteins)
roo.gif (957 bytes) facilitates the transfer of immunity to the newborn that is now in an unsterile pouch; around birth the mammary glands secrete a clear fluid that has free-floating cells and maternal immunoglobulins (similar to the colostrum of placental mammals)
roo.gif (957 bytes) mother can simultaneously produce milk of two different compositions for the joey that has emerged from the pouch but is not weaned and for the newborn

Emergence from the pouch

roo.gif (957 bytes) young first emerges from the pouch usually by falling out; this occurs after 185 days in reds, up to 298 days for western greys
roo.gif (957 bytes) mother's muscles control pouch size and opening; when she is alarmed, the pouch is pulled tight against her body so that the joey cannot emerge; she can relax the pouch and let the joey fall out; she can also contract the pouch and tip the joey out
roo.gif (957 bytes) joeys entering the pouch complete a somersault and end up facing the pouch opening
roo.gif (957 bytes) even after permanent emergency, the joey will continue to suckle on its usual teat for some months

TIMING OF SEXUAL MATURITY (months)
Species Male Female
Red 24 15-20
Western Grey 31 14
Eastern Grey 48 18
Euro 24 21

Social system

roo.gif (957 bytes) generally sedentary, home range (the area covered by an individual in the normal activities of feeding, mating, and caring for young) of a few kilometres across; home ranges are not defended
roo.gif (957 bytes) show fidelity to the home range, often returning after being forced away to find food in other places during drought

GROUPINGS OF INDIVIDUALS
Aggregation grouping of individuals at a resource (food, water, shade); individuals are not necessarily interacting
Mob a set of individuals whose home ranges overlap; commonly interact with each other; young animals and a lesser number of adults may disperse to different mobs; sufficient interaction to establish dominance hierarchies in relation to feed and shade for resting
Group social neighbourhood of an individual; members of a group communicate and interact as a unit; consist of less than 6 individuals; mainly females and their offspring, particularly daughters

 

Species Typical group size* Aggregation size Home range size**
Red 3 - 4 20 150 ha
Western Grey 2 - 16 100 ha
Eastern Grey 3 - 23 80 20 ha
Eastern Grey  (Tasmania) 5
Antilopine 3 - 12 50 female14 ha
male 76 ha
Euro 2 - 3 10-37 ha
* (from Dawson TJ, 1995, p29)
** depends on sex, season, habitat, time span

Status

roo.gif (957 bytes) None of the kangaroos are endangered, although locally populations may be limited.

References - books