Understanding the Unique Short-Beaked Echidna
The short-beaked echidna, scientifically termed Tachyglossus aculeatus, is sometimes referred to as the short-nosed echidna. This unique mammal is one of just four living echidna species and stands as the only representative of the Tachyglossus genus. With its combination of fur and spines, the echidna boasts an elongated snout that harbours a swift, specialised tongue, perfectly adapted for snatching up insects.
What sets the short-beaked echidna apart from other mammals is its egg-laying ability, a trait it shares exclusively with the platypus among contemporary mammals. This remarkable animal is equipped with robust forelimbs and powerful claws, making it an adept digger, capable of burrowing with impressive speed and strength. Its remarkable ability to thrive in underground habitats is complemented by an extraordinary tolerance for high levels of carbon dioxide and low oxygen conditions.
In terms of defence, the echidna lacks any aggressive mechanisms; instead, it resorts to curling into a spiny ball, which serves as an effective deterrent against potential threats. While it isn’t particularly well-suited to endure high temperatures, it adeptly avoids daytime activity during sweltering weather and can swim if the situation calls for it. The sensitivity of its snout is noteworthy, as it is equipped with mechanoreceptors and electroreceptors, which aid in navigating its environment with finesse.
Echidnas are predominantly solitary creatures, only converging for mating purposes. Unlike many other small mammals, they are primarily diurnal, actively foraging during daylight hours and using their long, sticky tongues to probe for food. When faced with danger, they instinctively curl into a ball, relying on their spines for protection.
During the chilly Australian winter months, echidnas enter a state of deep torpor, significantly reducing their metabolic rate to conserve energy. As the weather warms up, they emerge to mate. After this brief encounter, the male plays no part in raising the offspring. Females typically lay a single egg each year, and the hatchling, initially about the size of a grape, quickly develops on nutrient-rich milk. By the time they reach seven weeks, the spiky youngsters outgrow their mother’s pouch and are relocated to a burrow. It’s around the six-month mark when they gain independence and part ways with their mothers.
Habitat
Echidnas are found in a variety of habitats throughout Australia, including forests, grasslands, and deserts. They are generally found in areas with a reliable food source and plenty of shelter.
This species is widespread, making it the most common native mammal on the continent. It is also found in coastal and highland areas of eastern New Guinea, where it is known as the mungwe in local Daribi and Chimbu languages. While not currently endangered, the short-beaked echidna faces threats from human activities, including hunting, habitat destruction, and the introduction of non-native predators and parasites, which have led to declines in some areas of Australia.
The short-beaked echidna was first scientifically described by George Shaw in 1792, who initially named the species Myrmecophaga aculeata, mistakenly linking it to the giant anteater. Since Shaw’s original description, the species’ name has undergone several revisions: from M. aculeata to Ornithorhynchus hystrix, then Echidna hystrix, followed by Echidna aculeata, before finally being classified as Tachyglossus aculeatus. The genus name Tachyglossus translates to “quick tongue,” aptly describing the echidna’s rapid tongue movements used to capture ants and termites, while aculeatus refers to its “spiny” or “quilled” nature.
The short-beaked echidna is the sole species within the genus Tachyglossus, and it shares the family Tachyglossidae with the larger long-beaked echidnas of the genus Zaglossus found in New Guinea. The Zaglossus species, which include the western, Sir David’s, and eastern long-beaked echidnas, are notably larger than T. aculeatus and have a diet primarily composed of worms and grubs, in contrast to the ant and termite diet of the short-beaked echidna. Members of the family Tachyglossidae are unique as egg-laying mammals, and alongside the related family Ornithorhynchidae—which includes the platypus—they represent the only surviving monotremes in the world today.
The short-beaked echidna, typically measuring between 30 and 45 cm (12 to 18 in) in length, with a snout length of around 75 mm (3 in), these creatures weigh between 2 and 7 kg (4.4 to 15.4 lb). Interestingly, the Tasmanian subspecies, T. a. setosus, is generally smaller than its mainland Australian counterparts. The echidna’s head and body seem to merge due to the lack of an externally visible neck, and its earholes, positioned on either side of its head, lack external pinnae. The small eyes, about 9 mm (0.4 in) in diameter, are located at the base of its wedge-shaped snout. The snout houses the nostrils and mouth, which cannot open wider than 5 mm (0.2 in).
This species is distinguished by its covering of cream-colored spines, which are modified hairs made primarily of keratin, providing protection against predators. The spines are complemented by fur ranging in color from honey to dark reddish-brown and even black, covering most of the body except for the underside, face, and legs. The echidna’s fur is sometimes infested by one of the world’s largest fleas, Bradiopsylla echidnae, which measures about 4 mm (0.16 in) long.
Echidnas are remarkably adapted for digging, thanks to their short, robust limbs and strong claws, which allow them to burrow quickly and with great power. Their strength is so impressive that they can move heavy objects such as large logs, paving stones, and even a 13.5 kg (30 lb) stone. The power of their limbs comes from strong musculature, particularly around the shoulder and torso, giving them a mechanical advantage when digging.
Their hind feet have elongated, backward-curving claws designed for grooming between their spines. Like their monotreme relative, the platypus, echidnas have a low body temperature, typically ranging between 30–32 °C (86–90 °F). Unlike the platypus, however, echidnas are capable of entering periods of torpor or deep hibernation, allowing their body temperature to drop significantly, especially during the Australian autumn and winter.
Echidnas are known for their unique physiology, which includes a single orifice, the cloaca, for the passage of feces, urine, and reproductive products. Males possess internal testes and a highly unusual four-tipped penis. During the breeding season, females develop a temporary pouch where they incubate their young after laying a single egg.
The echidna’s musculature includes the panniculus carnosus, a large muscle just beneath the skin that allows the animal to change its shape, notably rolling into a defensive ball when threatened. The short-beaked echidna’s spinal cord is shorter than most mammals, terminating at the seventh thoracic vertebra, which is thought to aid in its ability to curl into a ball.
The echidna’s feeding adaptations are equally remarkable. Its long, sticky tongue, capable of extending up to 180 mm (7 in) beyond the snout, is its primary tool for capturing prey. The tongue is coated with glycoprotein-rich mucus that helps trap ants and termites, its main diet. The echidna’s tongue moves with great speed, capable of flicking in and out of the snout up to 100 times per minute. Once caught, prey is ground by backward-facing keratinous “teeth” located along the roof of the buccal cavity.
The stomach of the short-beaked echidna lacks secretory glands, and unlike other mammals, it has a nearly neutral pH and a cornified stratified epithelium resembling tough skin. Digestion occurs primarily in the small intestine, and indigestible materials like insect exoskeletons and soil are passed in the feces.
Echidnas are well-adapted to their burrowing lifestyle, capable of tolerating high levels of carbon dioxide and low levels of oxygen, which allows them to survive in challenging environments, including during bushfires or when underwater. Their heart rate can drop significantly in such situations to conserve oxygen.
The echidna’s senses are finely tuned to its environment. Its snout is equipped with mechanoreceptors and electroreceptors, enabling it to detect prey and navigate its surroundings. The echidna also has a well-developed sense of smell, which plays a crucial role in finding food and mates. Despite its poor eyesight, the echidna can distinguish between black and white and different shapes, which is sufficient for its survival.
Echidnas have a large prefrontal cortex, taking up 50% of their brain volume, a feature associated with complex behavior and reasoning. This has led to speculation about their cognitive abilities, which appear comparable to those of a cat or rat.
No comprehensive study has been conducted on the ecology of the short-beaked echidna, but several aspects of their behavior have been explored. These solitary creatures live alone and, aside from the burrow used for raising young, do not have a fixed shelter or nesting site. Unlike many other animals, echidnas do not establish and defend a specific territory; instead, they roam over wide areas, with ranges observed to vary between 21 and 93 hectares (52–230 acres), though some studies, such as one conducted on Kangaroo Island, have found ranges from 9 to 192 hectares (22–474 acres). On average, their range across various regions in Australia spans 40 to 60 hectares (99–148 acres). There is no significant correlation between range size and the echidna’s sex, although there is a slight relationship with their size. Echidnas can share overlapping ranges without conflict and may even share shelter sites when not enough are available for each individual.
Typically active during the day, short-beaked echidnas are not well-equipped to handle heat, as they lack sweat glands and do not pant. Therefore, in warmer weather, they adjust their activity patterns, becoming more active during the cooler hours of dawn and dusk, or even nocturnal. Body temperatures above 34°C (93°F) can be fatal to them, so they employ various strategies to maintain a safe temperature, such as adjusting blood flow to the skin to regulate heat loss. In areas with water, echidnas have also been observed swimming to cool down. The “thermoneutral zone” for echidnas is around 25°C (77°F), where their metabolism is most efficient for maintaining body temperature. They are endothermic and typically maintain a body temperature of around 32°C (90°F), though they can lower their metabolism, heart rate, and body temperature as needed.
Echidnas enter light torpor throughout the year, but during the Australian winter, they may enter deep hibernation in both cold and temperate regions. During hibernation, their body temperature can drop as low as 4°C (39°F), their heart rate slows to 4–7 beats per minute (down from 50–68 beats per minute at rest), and they may breathe only once every three minutes. Their metabolic rate can decrease to one-eighth of its normal level. Echidnas begin preparing for hibernation between February and April, reducing their food intake and entering brief periods of torpor. Males start hibernating earlier than females, who begin later if they have reproduced. On average, echidnas experience 13 separate torpor bouts during hibernation, interspersed with periods of arousal lasting about 1.2 days, often coinciding with warmer weather. Males typically end hibernation by mid-June, while reproductive females become active again in July and August; non-reproductive females and young echidnas may continue hibernating for another two months. Echidnas exhibit a low metabolic rate, around 30% of that of placental mammals, making them the least energy-consuming mammals—a trait shared by other animals that feed on ants and termites or those that burrow.
Even though hibernation is not strictly necessary for survival—echidnas begin hibernating when the weather is still warm and food is abundant—it may help them conserve energy and optimize foraging efficiency. One hypothesis suggests that echidnas may have evolved from ectothermic ancestors and adopted periodic endothermy to support quicker development of their young. Supporting this theory, males hibernate earlier than females, possibly to prepare for spermatogenesis before mating, while females and young have a delayed cycle. During hibernation, echidnas remain in well-covered shelters.
Echidnas have a varied diet, primarily consisting of ants and termites, which they locate using their highly sensitive snouts. They also hunt beetles, earthworms, and other small invertebrates. They avoid ants and termites that secrete repellent chemicals, instead preferring the eggs, pupae, and winged phases of these insects. Their diet shifts depending on prey availability, with termites favored in drier areas. Despite their solitary nature, echidnas do not defend specific territories but will dig rapidly into the ground to evade predators. They protect their vulnerable underside by curling into a ball and can emit a pungent liquid as a deterrent. Males have vestigial spurs on their hind legs, possibly remnants of a once-functional defensive weapon.
Echidnas likely play a crucial role in maintaining ecosystem health through bioturbation, the reworking of soil by their digging activities. With each echidna moving up to 204 cubic meters (7,200 cubic feet) of soil annually, they contribute significantly to soil turnover and aeration. This, combined with their widespread distribution across Australia, suggests they are key species in their environments.
Echidnas are adaptable, found in various habitats across Australia, from forests and grasslands to arid regions and even urban outskirts. They are also present in southern New Guinea, where they inhabit open woodlands. Echidnas are strong swimmers and have been seen cooling off in dams and crossing streams, even swimming in the seas off Kangaroo Island, with only their snout visible above water, functioning as a snorkel.
Reproduction
The solitary short-beaked echidna seeks out a mate between May and September, though the exact timing can vary depending on the region. Prior to the mating season, the size of the male’s testes increases significantly, sometimes tripling in size, as spermatogenesis begins. Both male and female echidnas emit a strong, musky odor during this period, which is thought to be an aphrodisiac, by inverting their cloacas and rubbing them on the ground, secreting a glossy liquid. Courtship behavior was first documented in 1989, revealing that males actively pursue females, sometimes forming “trains” of up to 10 males following a single female. These courtship trains can persist for up to four weeks, with males coming and going throughout the process. In cooler regions like Tasmania, females may mate soon after emerging from hibernation.
Before mating, the male spends time sniffing the female, particularly her cloaca. This can take several hours, and the female has the option to reject the male by curling into a protective ball. If the female accepts, the male may roll her onto her side, and they align themselves abdomen-to-abdomen in a small, shallow depression. They can face each other head-to-head or align head-to-tail. If multiple males are present, competition for the female may occur. The male’s unique four-headed penis, which resembles that of reptiles, uses one side at a time, with the other half remaining inactive between ejaculations. Each ejaculate contains sperm bundles of around 100, enhancing sperm motility and potentially increasing the chances of successful fertilization in the presence of competition. Mating can last anywhere from 30 minutes to three hours, and typically results in the fertilization of a single egg.
Fertilization occurs in the oviduct, and the gestation period lasts between 21 and 28 days. During this time, the female constructs a nursery burrow. Once gestation is complete, she lays a single egg, which is soft, leathery, and cream-colored, measuring 13 to 17 mm in diameter and weighing 1.5 to 2 grams. The egg is laid directly into a backward-facing pouch that the female develops on her abdomen. Some females continue foraging during the incubation period, while others remain in their burrows. The egg hatches approximately ten days later within the pouch, with the embryo using a specialized egg tooth to break through the shell.
Puggles
Newly hatched echidnas, known as “puggles,” are tiny, about 1.5 centimeters long, and weigh between 0.3 and 0.4 grams. Despite being semitranslucent and underdeveloped, they have well-formed front limbs and digits that allow them to climb onto their mother’s body. Puggles attach themselves to specialized areas of the mother’s skin called milk areolae, as echidnas do not have nipples. These patches secrete milk through 100 to 150 pores, which the puggles consume by sucking. Puggles feed intermittently, often ingesting large amounts of milk at once, and mothers may leave them alone in the burrow for up to ten days while they forage. In captivity, puggles have been observed gaining up to 20% of their body mass in a single feeding session lasting one to two hours.
As puggles grow, they reach a weight of around 200 grams and are left in the burrow while the mother continues to forage. By the time they weigh around 400 grams, after approximately two months, they are ejected from the pouch as their growing spines become uncomfortable for the mother. Juveniles are then left in covered burrows and are vulnerable to predation. Suckling gradually decreases, and by about six months, the young are fully weaned. The entire lactation period lasts around 200 days, and the young leave the burrow after 180 to 205 days, weighing between 800 and 1,300 grams. After this, there is no further contact between the mother and her offspring.
The composition of the mother’s milk changes as the puggle matures. Initially, the milk is dilute, with low fat content, but it becomes more concentrated as the puggle grows. Near weaning, the milk’s protein content increases, likely to support the development of keratin for the young echidna’s hair and spines, essential for protection against the cold and predators. The milk’s carbohydrate components are primarily fucosyllactose and saialyllactose, and it has a high iron content, giving it a pink hue. The iron-rich, low-lactose milk is distinct from that of placental mammals, with lactose production thought to be similar to that of the platypus.
Once the puggle is old enough to be independent, it will leave its mother and set out on its own. From this point on, the mother has no further role in the puggle’s care and development. Echidnas are generally solitary animals, and they do not form strong social bonds or live in family groups like some other animals do.
Overall, the mother and puggle relationship in echidnas is relatively short-lived, with the mother providing the necessary nutrients and care during the early stages of the puggle’s development before it sets out on its own.
The age at which echidnas reach sexual maturity is not well-defined, but it is estimated to be between four and five years. A 12-year study suggested that sexual maturity occurs between five and 12 years, with reproduction frequency varying from every two to six years. In the wild, the short-beaked echidna typically lives about 10 years, though some have been known to live up to 40 years. The longest-lived echidna on record reached 49 years in a Philadelphia zoo. Echidnas exhibit slower rates of reproduction and metabolism compared to other mammals, which, along with their low body temperature, contributes to their longevity. Their body temperature rarely exceeds 33°C (91°F), even when they are not hibernating, which may also play a role in their extended lifespan.
Conservation Status of the Short-Beaked Echidna
The short-beaked echidna is widespread across much of temperate Australia and lowland New Guinea, and fortunately, it is not currently listed as endangered. In Australia, this species thrives in a variety of habitats, including urban fringes, coastal forests, and the arid inland. It is particularly abundant in Tasmania and on Kangaroo Island.
Despite their widespread distribution, short-beaked echidnas face several threats. One of the most significant is motor vehicle collisions, which, along with habitat destruction, have caused localized declines in their populations. While land clearance has heavily impacted other species, the short-beaked echidna has been somewhat more resilient, as it does not require highly specialized habitats—only a steady supply of ants and termites. They can survive in areas where trees have been felled, as long as fallen logs remain, providing shelter and food sources. However, in regions completely cleared for monoculture farming, such as wheat fields, echidna populations have disappeared. Over a decade, studies in Victoria found that about one-third of echidna deaths reported to wildlife authorities were due to vehicle collisions. Traffic accidents are the leading cause of injury for echidnas brought to wildlife rescue centers. Research suggests that echidnas often use drainage culverts to cross roads, indicating that installing more of these culverts could reduce roadkill incidents in high-traffic areas, particularly in rural regions and national parks.
Despite their protective spines, echidnas are vulnerable to various predators. Young echidnas are particularly at risk from birds of prey, Tasmanian devils, dingoes, snakes, goannas, cats, and red foxes. Goannas, known for their digging ability and acute sense of smell, were likely the primary predators of echidnas before the introduction of non-native mammals. Dingoes have been observed flipping echidnas onto their backs to attack their vulnerable underbellies. A tracking study on Kangaroo Island identified goannas and feral cats as the main predators, though foxes, absent on the island, would likely pose a significant threat elsewhere.
Echidnas have also been a food source for both Indigenous Australians and early European settlers. In New Guinea, hunting pressure has increased over time, leading to a decline in echidna populations and a reduction in their range. Traditionally, hunting echidnas was taboo in some cultures, but as Western influences grew and hunting dogs became more common, echidnas became easier to track and hunt, further threatening their survival.
The introduction of parasitic tapeworms, such as Spirometra erinaceieuropaei, poses another threat to echidnas, often resulting in fatal infections. This parasite is spread through shared water sources, where echidnas can contract the infection from infected dogs, foxes, cats, and dingoes. The risk is particularly high in arid regions with limited water sources. In addition to tapeworms, echidnas can be affected by protozoans and herpes-like viruses, though the impact of these infections on echidna health and population dynamics remains poorly understood.
Captive breeding of short-beaked echidnas has proven challenging, although they are generally easy to keep healthy in captivity. Success in breeding has been limited, with Perth Zoo achieving notable success in 2009 and again in 2015, when they bred the first zoo-born echidnas to survive to maturity. Globally, only a handful of zoos have managed to breed short-beaked echidnas, with most efforts occurring in the Northern Hemisphere. These attempts are often complicated by the echidnas’ relatively infrequent reproductive cycles and the animals’ adaptation to different seasonal cycles in the Northern Hemisphere. The difficulty in breeding echidnas in captivity has significant conservation implications, especially for the more endangered echidna species in the genus Zaglossus.
Fascinating Facts About the Short-Beaked Echidna
- Cultural Significance: The short-beaked echidna plays a prominent role in the animistic culture of Indigenous Australians. It is a totem for some groups, such as the Noongar people from Western Australia. Many Indigenous myths surround the echidna; one legend tells of how it was created when a group of young men, hunting at night, mistook a wombat for prey. After losing sight of it, the wombat turned into an echidna, using the spears thrown at it as spines for its defense.
- Iconic Australian Animal: The short-beaked echidna is an iconic figure in Australia, featured on the country’s smallest denomination, the five-cent coin. Additionally, it appeared on a special $200 commemorative coin released in 1992.
- Olympic Mascot: Millie the Echidna was one of the three official mascots for the 2000 Summer Olympics held in Sydney. Millie represented the millennium, symbolizing the future and the coming technological era.
- Pop Culture Appearance: The short-beaked echidna gained international fame through the fictional character Knuckles the Echidna from the Sonic the Hedgehog series. Knuckles, a red echidna with superhuman strength, became one of the most recognized video game characters worldwide.
The next time you come across an echidna in the wild, take a moment to appreciate this amazing animal and all that it has to offer. The echidna is truly a marvel of nature, and one that we should all work to protect.
