Red Kangaroo (Macropus rufus) Fact Sheet: Physical Characteristics

Body measurements

Data sources: Novak (1999), Wilson & Mittermeier (2015)

General

• Largest of the marsupial mammals; the largest kangaroo
• Has small head, large dark eyes, large ears, a thick tail used as a prop when sitting or standing and for balance when hopping (Nowak 1999)
• Distinguished by a white underbelly and white patch from the corner of the mouth to the base of the ear (Newsome 1995)

Pelage

• In general, coat is short, blue-grey to red on back; white on belly (Grzimek & Ganslosser 1990)
• Females usually a smoky blue but can also be red like many males (Dawson 1995)
  • In northwest, both sexes are typically red
• Tip of tail pale (not dark like grey kangaroos) (Dawson 1995)
• Paws and toes are dark (Staker 2006)
• Surface of nose is hairless and well-defined (Grzimek & Ganslosser 1990)
  • Skin on nose grainy and dusky in color (not shiny black like wallaroos) (Dawson 1995)
• Black and white patch on side of muzzle; broad white stripe from corner of mouth to ear (Dawson 1995)
• Very dense and fine fur: 62 fibers/mm (62 fibers/0.04 in) (Tyndale-Biscoe 2005; Staker 2006)
  • Increases insulation in both hot and cold weather
  • Texture feels like soft wool, unlike fur of other kangaroos

• Marked sexual dimorphism (Newsome 1995)
  • Males larger and nearly twice as heavy as females
  • Males' shoulders and arms proportionally larger than that of females
• Unlike most other kangaroos, male and female red kangaroos often have coats of different colors (Jarman 1989)
  • Sex-specific coloration visible even in juveniles
  • Some males may be female-colored; some females, male-colored

Adaptations to Desert Heat (Tyndale-Biscoe 2005) 

• Seek shelter under saltbushes or mulga bushes
• Reduce activity to a minimum
• Postures helps avoid heat load:
  • Stand with large tail pulled under body
  • Tail is shaded from sun but air can flow around body to help cooling
• Panting
  • Enhanced by larger nasal passages than those of other kangaroos
  • More efficient than sweating, because it cools core body temperatures, especially in the brain
• Sweating
  • Sweat only when exercising
  • To conserve water, stop sweating when they stop hopping, even if body temperature still high
• Spreading saliva from maxillary salivary glands (which is different than digestive saliva) on forearms
  • Saliva has less protein and phosphates than digestive saliva from parotid gland
  • Water evaporation on arms cools blood in large veins in forearm
• Can maintain plasma volume when dehydrated (Denny & Dawson 1975)
  • 8% drop of plasma volume, even when body weight decreases by 20% (Schmidt-Nielsen 1964)
  • Camels and burros have similar physiologies to kangaroos (Schmidt-Nielsen 1964) (Yousef et al. 1970)
    • Camels lose less than 10% of plasma volume
    • Burros lose 7% of plasma volume
• Urea from urine is recycled in the foregut, saving valuable protein and water (Dawson 1995)
• Juvenile kangaroos are more sensitive than adults to extremes of cold or heat (Munn et al. 2007):
  • Red kangaroos regularly experience temperatures below 0°C (32 °F) and in excess of 45° C (113 °F)
  • In order to cope with thermal extremes, juveniles work harder than adults to maintain their body temperature
    • At low temperatures juveniles take larger breaths than adults
    • At high temperatures juveniles breathe faster

Other Physical Characteristics

• Features shared with all other members of the taxonomic order Diprotodontia (Nowak 1999; Agar 2008):
  • A large outward projecting incisor on each lower jaw
  • Second and third digits of hind foot are fused (syndactyly), joined by a skin covering with a single claw
• Features shared with all macropods (Nowak 1999):
  • Long narrow feet
  • Hind limbs longer and stronger than forelimbs
  • Forelimbs have 5 digits
  • Pouch opens forward, has 4 teats
  • Very small or non-existent vocal cords (Symington 1898)
• Hind limbs in larger kangaroos have unusual properties compared to other animals (McGowan et al. 2008; Bennett & Taylor 1995):
  • Tendons that extend the ankle generate larger than normal stresses and store more elastic strain energy
  • Higher elastic strain energy results in a reduced tendon safety factor
  • The need to minimize tendon and bone stresses limits the largest body size possible for hopping kangaroos and wallabies
• Large ears can move independently, through 180° (Tyndale-Biscoe 2005)
• Visual capacity of large kangaroos and wallabies similar to that of rabbits and ungulates (Tyndale-Biscoe 2005)
  • Eyes high on skull
  • Field of vision wide - a tammar wallaby can see 324° for detecting movement in almost any direction
  • Overlap of vision from both eyes is about 25°
    • A rabbit has about 24° of binocular vision
    • A cat has 98° of binocular vision
• Teeth move forward slowly and eventually fall out, making room for molars erupting behind (Nowak 1999)
  • Four sets of molars thus erupt in a lifetime
  • Animals with similar tooth development: elephants, manatees
  • Very old kangaroos may have only one tooth left in each jaw (Marshall & Corruccini 1978)
• Toenails shorter than those of other kangaroo species (Staker 2006)
• Paws and forearms used only occasionally (Weisbecker & Sanchez-Villagra 2006):
  • Pulling down branches
  • Fighting
  • Grooming
  • Holding open the pouch for cleaning

The fur of the red kangaroo has a distinct, wooly texture, unlike other kangaroos.

Its coat provides insulation against both hot and cold weather.

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

Agar (2008)
Bennett & Taylor (1995)
Dawson (1995)
Denny & Dawson (1975)
Grzimek & Ganslosser (1990)
Jarman (1989)
Marshall & Corruccini (1978)
McGowan et al. (2008)
Newsome (1995)
Nowak (1999)
Schmidt-Nielsen (1964)
Staker (2006)
Symington (1898)
Tyndale-Biscoe (2005)
Weisbecker & Sanchez-Villagra (2006)
Yousef et al. (1970)