Echidna
TAXONOMIC CLASSIFICATION
| Class | Mammalia | monotremes, marsupials, & placental or eutherian mammals
fur, ability to maintain constant body temperature by internal mechanisms |
| Order | Monotremata | with one hole platypus & echidnas lay eggs, have no teats, single opening (cloaca) for waste products and reproduction (like reptiles and birds), no whiskers, no teeth, no external ears |
| Family | Tachyglossidae | |
| Genus | Tachyglossus | tachy rapid glossus tongue |
| Species | aculeatus | spiny |
| Common Names |
short beaked echidna, spiny anteater, native porcupine
the common name of echidna comes from an earlier scientific name of Echidna hystrix which referred to the Greek goddess Ekhidna who was half reptile, half mammal - reference to an animal that had fur and lactated but layed eggs |
Appearance
GENERAL
- medium-sized, stocky body, small head with long snout, sharp spines on back and sides, very strong
SIZE
- Weight: 2-7 kg (4-15lbs)
- Length: 30-45cm (12-18 inches)
- spines intermingle with fur
- density of fur varies with habitat - dense in Tasmania and in alpine regions; in dry and northern areas, fur is sparse
- covered with tough, hairless skin containing glands and sensory receptors nostrils are at the end of the snout
- used to crush large prey items so that they will fit into the mouth
- tongue can extend 18cm (7in) beyond the end of the snout; flicks in and out up to 100 times per minute; tip of the tongue can bend into a U shape allowing it access to the narrow galleries of ant and termite nests
- stickiness of the tongue caused by saliva the consistency of treacle
- front claws are more powerful than the hind ones, used for digging; the hind claws are used in grooming
- young have nonvenomous spines on the inside of their hind feet; males retain one or both while females may retain one (rare)
Distribution
RANGE
- found throughout Australia; have overlapping home ranges but tend to be solitary except for mating
- home range of 50 hectares on average across different habitats
HABITAT
- very adaptable
- hot arid interior (Simpson Desert) to above the snow line in alpine regions
- flat scrub with sand and tussock to steep rocky mountain country
Feeding
DIET
- mainly ants and termites, but also earthworms, small beetles, larvae of moths and beetles
- avoid the larger biting ants; prefer larvae, pupae, queen, winged ants (not immune to ant bites; roll over and scratch to dislodge biting ants) prefer termites to ants - prefer queens and nymphs; termites live in larger colonies and ants have a larger proportion of their mass as non-digestible exoskeleton
METHODS OF FEEDING
- trap ants by lying on top of the mound with tongue extended on the surface; ants walk onto tongue; can continue for hours
- use front claws to turn over leaf litter or rip into rotting timber
- use snout to turn over soft soil
- use front claws to burrow into mounds - usually in late winter and early spring in the late afternoon when the queens move into the surface galleries thus ensuring the greatest return for the least expenditure of energy
FEEDING RATE
- for a 3kg animal - 200gms of ants in 10 minutes
Lifestyle
SHELTER
- no fixed nest site, shelters under thick bushes, in hollow logs, under piles of debris, or in caves or crevices; use burrows constructed by wombats and rabbits
EFFECTS OF AMBIENT TEMPERATURE
- in cold areas, hibernates for 6-28 weeks of the year depending on local conditions, and factors related to reproduction; males can go into hibernation earlier than females with young; yearlings that don't breed stay longer in hibernation
- have no sweat glands and do not pant, so need to shelter from heat - activity depends on temperature; in hot areas, tends to feed at night; temperate areas commonly feeds around dawn and dusk; when cold may be active in the middle of the day
LIFESPAN
- live more than 10 years; record of 49 years in a Philadelphia zoo
Lifestyle
SHELTER
- no fixed nest site, shelters under thick bushes, in hollow logs, under piles of debris, or in caves or crevices; use burrows constructed by wombats and rabbits
EFFECTS OF AMBIENT TEMPERATURE
- in cold areas, hibernates for 6-28 weeks of the year depending on local conditions, and factors related to reproduction; males can go into hibernation earlier than females with young; yearlings that don't breed stay longer in hibernation
- have no sweat glands and do not pant, so need to shelter from heat - activity depends on temperature; in hot areas, tends to feed at night; temperate areas commonly feeds around dawn and dusk; when cold may be active in the middle of the day
LIFESPAN
- live more than 10 years; record of 49 years in a Philadelphia zoo
Nearest relatives
Zaglossus bruijni
- the long-beaked echidna lives in the highlands of Papua New Guinea and eats mainly earthworms so it is affected by clearing of forests
IN AUSTRALIA
- the other monotreme, the platypus
Predation
PREDATORS
- dingoes, goannas, and snakes will eat the young
- once adult, the echidna has no real enemies
WEAPONS & TACTICS
- no defensive or offensive weapons
- a threatened echidna pulls its head in and curls into a ball to protect its belly so that all that is presented is a ball of spines
- in soft soil, it can also dig in and disappear rapidly climb into trees or climb fences
Reproduction
BREEDING SEASON
- May/June to September (winter)
COURTSHIP
- both sexes give off a pungent odour during the mating season so it is likely that this is how males find females
- trains of up to 10 males may follow nose to tail after a mature female
- males compete for females by engaging in head-to-head pushing and bumping contests where the larger animal will be the winner
MATING
- the male uses his snout to investigate the female's body in general and the cloaca in particular - this can last for 5 hours
- matings in captivity have been observed with the animals on their sides, abdomen to abdomen
EGGS
- no more than one young every year; in cold areas, females may mate only every second year
- eggs are soft-shelled, similar to reptile eggs
- gestation period during which the female retains the egg in her reproductive tract lasts between 21 and 28 days
- a single egg is transferred from the cloaca to the incubation pouch which is formed by muscle contraction
- embryo has a single egg tooth to tear open the shell to hatch after about 10 days in the pouch
- the young echidna is called a puggle
LACTATION
- milk is secreted from ducts onto two circular patches on the mother's belly called the milk patch or aerola; the young doesn't lick the milk from the skin but sucks it from the aerola
- early in lactation, the milk is rich in iron; this is thought to be because the young are so small that their livers are not able to store enough iron to tide them over until they can forage for themselves
LEAVING THE POUCH
- when the puggle is too prickly to carry, the mother leaves it in a newly-dug burrow and returns every few days to feed it
- a young echidna emerges from the burrow at about 6 months and is weaned about 4 weeks later
Senses
EYESIGHT
- not an essential sense
- have colour vision
- extent of 3D vision probably restricted
HEARING
- can detect vibrations from the ground especially through the snout
- detect changes in position, speed, and movement in three dimensions
SNOUT
- touch receptors
- temperature receptors sensitive to cold and heat
- electroreceptors (similar to platypus)
SMELL
- used in social situations such as mating
- monitoring the environment
References
- Echidnas of Australia and New Guinea, M Augee & B Gooden, 1993. University of New South Wales Press Ltd, Sydney
- Encyclopedia of Australian Wildlife, Reader’s Digest Australia Pty Ltd, 1997. Reader’s Digest (Australia) Pty Ltd, Surrey Hills
- Complete Book Of Australian Mammals, R Strahan (ed), 1983. Angus & Robertson Publishers, London