Tachyglossus aculeatus is the most widely distributed extant monotreme. Subspecies of T. aculeatus are distributed throughout southern and eastern New Guinea, mainland Australia, Kangaroo Island, and Tasmania. This range includes large portions of the three countries of Australia, Indonesia, and Papua New Guinea. ("Tachyglossus aculeatus", 1991; Aplin, et al., 2008; Groves, 2005)
Short-beaked echidnas thrive in a variety of habitats including open woodlands, savanna, agricultural areas, semi-arid, and arid regions. Both coastal and highland areas in New Guinea are home to Tachyglossus aculeatus, along with a range of ecosystems in Australia from mild coastal regions to above snowline. Short-beaked echidnas have a broad altitudinal range from sea level to at least 1,675 meters. (Aplin, et al., 2008; Nicol and Anderson, 2007a)
Short-beaked echidnas are medium-sized mammals ranging in length from about 30 to 40 cm and in weight from about 2 to 7 kg. Depending on the subspecies and location, males or females may be larger. Short-beaked echidna spines are one of their most distinguishing characteristics. These spines cover the entire dorsal surface, including a small tail. Fur is also present and may be even longer than the spines in some subspecies. Tachyglossus aculeatus lacks external pinnae and teeth but does have hard pads in the back of the mouth. Short-beaked echidnas possess several adaptations to their foraging habits including tubular snouts, long sticky tongues, and front paws for digging. Males have non-venomous spurs on the ankles of their hind legs and females have pouches on their undersides. Both males and females have a cloaca through which feces, urine, and, in females, eggs pass. Males have penises they extend through the cloaca during mating. Short-beaked echidnas, and other monotremes, have low metabolic rates and low body temperatures, which may be related to such factors as diet and environmental variation. Short-beaked echidnas have larger brains than would be expected for their body mass. The cerebral cortex, in particular, is large and highly convoluted. (Nicol and Anderson, 2007a; Riek, 2008)
Tachyglossus aculeatus has a courtship period between June and August that can last between a few days and several weeks depending on geographic region and subspecies. Females may be pursued by one or several males during this period. Observations of multiple males following individual females have led to the term “echidna train.” Females will mate with only one male per season. (Nicol and Anderson, 2007a)
Gestation in Tachyglossus aculeatus lasts about 23 days, after which the female will lay a single soft-shelled egg in her pouch for incubation. Eggs hatch 10 or 11 days later. Short-beaked echidnas exhibit a long lactation stage lasting between 150 and 200 days depending on geography and subspecies. When the young leave the pouch three months later, they are covered with spines. Maturation time is lengthy. Young reach full adult size after three to five years. Hatchlings have a mass of about 0.3 kg but will grow to weigh 0.7 to 2.1 kg by weaning. Weaning mass is 28 to 48% of adult mass. ("Tachyglossus aculeatus", 1991; Aplin, et al., 2008; Nicol and Anderson, 2007a)
Subspecies vary in their strategies of caring for young. Short-beaked echidnas on Kangaroo Island forage with the young in the pouch immediately post-hatching. After 45 to 55 days, mothers will deposit their young in nursery burrows, where the young will remain until weaning. Mothers return every five to ten days to nurse the young. Short-beaked echidnas in Tasmania remain in nursery burrows with the young for 25 to 35 days post-birth. Mothers then return to the burrow every three to five days to nurse. Other subspecies exhibit variations of parental care ranging between these two extremes. Mothers do not have nipples or teats, but nurse young through pores connected to their paired mammary glands. (Nicol and Anderson, 2007a)
The longest recorded lifespan for Tachyglossus aculeatus is 50 years in captivity. There are anecdotal accounts of wild individuals living as long as 45 years. There is no doubt this species is particularly long-lived, especially for its size. A lifespan of 50 years is 3.7 times longer than would be expected based on echidna body size. Other long-lived mammals have been observed to have peroxidation-resistant membrane composition, which describes the ratio between polyunsaturates and monounsaturates in membrane lipids. Short-beaked echidna membranes were found to have lower polyunsaturate and higher monounsaturate levels than expected. This composition indicates peroxiclation-resistant cellular membranes in T. aculeatus. Lifespan is also associated with the production of free radicals, which is proportional to metabolic rate. Short-beaked echidnas have notably low metabolic rates, with the exception of times of arousal from torpor. During these arousal periods, metabolic rates increase by up to nine times that of basal metabolic rates and free radical production is high. Therefore, T. aculeatus is thought to have stress resistance that contributes to a long lifespan. A large and complexly-structured brain may be involved with longevity in T. aculeatus. Such brain characteristics are often correlated with life history traits like slow maturation and single births in other mammals. These traits, in turn, correlate with a long lifespan. (Hulbert, et al., 2008; Nicol and Anderson, 2007a)
Short-beaked echidnas are semi-fossorial, digging in substrate for hibernation cover and to construct nursery burrows. They decrease energy usage by hibernating from early autumn to late spring. Short-beaked echidnas reduce their body temperature to 8 to 10 degrees C during torpor and use behavioral thermoregulation to maintain that preferred body temperature. During early hibernation, individuals prefer cooler soil temperatures compared with the coldest period of hibernation, at which time they will move to warmer hibernacula. During hibernation there are periodic arousals from torpor. The timing of hibernation seasons varies by subspecies, geographic location, sex, and reproductive state. Short-beaked echidnas are flexible in their exploitation of substrates for hibernacula, commonly using leaf litter and grass tussocks. (Nicol and Anderson, 2007b; Nicol and Anderson, 2007a)
Short-beaked echidnas nest at temporary sites, and have overlapping home ranges. Their movements depend on food availability and not territoriality. ("Tachyglossus aculeatus", 1991; Nicol and Anderson, 2007a)
Short-beaked echidnas sense other echidnas predominantly through smell. Recent findings suggest feces piles act as an important intra-specific form of communication. (Elridge and Mensing, 2007; Nicol and Anderson, 2007a)
Adult short-beaked echidnas eat ants, termites, and other invertebrates. They make foraging pits by disturbing the soil when looking for food, and they prefer foraging under the canopies of large trees. Their long snouts and sticky tongues reflect their specialized diet. Short-beaked echidnas dig into ant and termite nests with their front paws and poke their long, sticky tongue into nest crevices and grinds insects with its tooth pads. Their foraging habits make separating soil from food difficult. Thus, much of their feces consists of soil. (Elridge and Mensing, 2007; Nicol and Anderson, 2007a)
Predation is not a major threat to short-beaked echidnas, even though feral cats, pigs, dingoes, and goannas are occasional predators. Animal predators are mostly a threat to young in burrows and to subadults. Adults escape predation by hiding beneath rocks or logs, or digging into the ground until only the spiny back is exposed. Short-beaked echidnas can also curl up to protect their undersides. Despite the minimal defense of many hibernaculum materials, predation on hibernating individuals does not seem to be a problem. After introduced predators, the biggest influence on T. aculeatus mortality is the threat of motor vehicles. Over-hunting by humans may become a problem in some areas of New Guinea. (Aplin, et al., 2008; Nicol and Anderson, 2007a)
The foraging pits short-beaked echidnas create become resource traps and affect soil biogeochemistry. Tachyglossus aculeatus may be important in maintaining proper nutrient circulation through small-scale patchiness in semi-arid regions. (Elridge and Mensing, 2007)
Short-beaked echidnas are hunted for food and for ceremonial purposes, especially in New Guinea. They maintain small-scale patchiness, which is an important ecosystem service that keeps semi-arid regions functioning properly. Their diet of ants, termites, and other invertebrates may contribute to the control of these species. (Aplin, et al., 2008; Elridge and Mensing, 2007; Nicol and Anderson, 2007a)
Because short-beaked echidnas can live in agricultural areas, they may disrupt fields and gardens while foraging. (Nicol and Anderson, 2007a)
As of 2008, the IUCN listed Tachyglossus aculeatus as a species of Least Concern. Short-beaked echidnas have a broad distribution, a large total population with a stable trend, and are tolerant of many habitat types. They occur in protected areas and appear to lack major threats. The IUCN did suggest monitoring the number of T. aculeatus killed on major tourist roads. (Aplin, et al., 2008)
Tanya Dewey (editor), Animal Diversity Web.
Michelle Cason (author), University of Alaska Fairbanks, Link Olson (editor, instructor), University of Alaska Fairbanks.
Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.
living in landscapes dominated by human agriculture.
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
active at dawn and dusk
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
union of egg and spermatozoan
A substance that provides both nutrients and energy to a living thing.
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
Referring to a burrowing life-style or behavior, specialized for digging or burrowing.
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.
An animal that eats mainly insects or spiders.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
having the capacity to move from one place to another.
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
having more than one female as a mate at one time
rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.
communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them
scrub forests develop in areas that experience dry seasons.
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
digs and breaks up soil so air and water can get in
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
1991. Tachyglossus aculeatus. Pp. xviii-xix, 2-3 in R Strahan, ed. The Australian Museum Complete Book of Australian Mammals. New South Whales: Cornstalk Publishing.
Elridge, D., A. Mensing. 2007. Foraging pits of the short-beaked echidna (Tachyglossus aculeatus) as small-scale patches in a semi-arid Australian woodland. Soil Biology & Biochemistry, 39: 1055-1065.
Groves, C. 2005. Tachyglossus aculeatus. Pp. 1-2 in D Wilson, D Reeder, eds. Mammal Species of the World: A Taxonomic Reference, Vol. 1. Washington: Smithsonian Institution Press.
Hulbert, A., L. Beard, G. Grigg. 2008. The exceptional longevity of an egg-laying mammal, the short-beaked echidna (Tachyglossus aculeatus) is associated with peroxidation-resistant membrane composition. Experimental Gerontology, 43: 729-733.
Nicol, S., N. Anderson. 2007. Cooling rate and body temperature regulation of hibernating echidnas (Tachyglossus aculeatus). Journal of Experimental Biology, 210: 586-592.
Nicol, S., N. Anderson. 2007. The history of an egg-laying mammal, the echidna (Tachyglossus aculeatus). Ecoscience, 14: 275-285.
Riek, A. 2008. Relationship between metabolic rate and body weight in mammals: effect of the study. Journal of Zoology, 276: 187-194.