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biologie artikel (Interpretation und charakterisierung)

Kangaroos





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





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Appearance
SPECIES

MALES

FEMALES
HEIGHT*

WEIGHT
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





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Behaviours



SOCIAL INTERACTION

these are actions that promote the unity of a group; don\'t include either displays of aggression or reproductive behaviour

BETWEEN GROUP MEMBERS:

mutual nose touching and sniffing, touching the lips of another, other touching and sniffing, grooming others, nuzzling a female\'s pouch

submissive behaviour - one animal, often smaller, holds its body close to the ground and its head may quiver

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:

mother grooms a young at foot while it is suckling or just after

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

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

play-fighting



AGGRESSION

fights (\'boxing\') between large males are rare

most fights are one-sided and end quickly; the challenged individual usually moves away

a submissive \'cough\'/cluck is heard in eastern greys, wallaroos, euros but not in reds

threat displays indicate an intention to act aggressively; these include upright posture, stiff-legged walking, pulling on grass or bushes





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Distribution



Between them, the kangaroos range over most of Australia.

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





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Feeding



reds and greys may feed in large mobs - size depends on the quality of food

most active at dawn and dusk; relatively inactive in middle of both day and night

time spent grazing varies seasonally between 7 and 14 hours

rest during the day in the shade of woodland; move onto grasslands to feed

eat a variety of plants but mainly grasses





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Hopping



kangaroos are unique in being the only large animals that use hopping for locomotion

they walk at slow speeds and start hopping as speed increases



ENERGETICS OF HOPPING


when hopping starts its costs are high

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

for red kangaroos, the most comfortable speed is 20-25 km/hr

as speed increases up to about 40 km/hr, the hopping rate remains constant but the length of the hop increases

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

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





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Mortality




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





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Reproduction



GENERAL

reds, euros, wallaroos - breed continuously under good conditions; greys are usually seasonal breeders

marsupial reproduction depends on lactation to nourish the poorly developed young; consequently, female marsupials have a greater investment in the care of their young

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

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

kangaroos have a relatively long gestation period compared to other marsupials ranging from about 31-36 days

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

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

in the euro, wallaroos, and red the young is continuously attached to the nipple until 120-130 days

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)

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)

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

young first emerges from the pouch usually by falling out; this occurs after 185 days in reds, up to 298 days for western greys

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

joeys entering the pouch complete a somersault and end up facing the pouch opening

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





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Social System



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

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

 
 




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