Short-beaked Echidna (Tachyglossus aculeatus) Fact Sheet: Behavior & Ecology

Mainly nocturnal

• Most active at night, evening, and early morning (Augee et al. 2006; Nicol 2015b; Nicol 2015a; Clemente et al. 2016)
  • Also regularly active during the day (particularly in colder areas), unlike most native Australian mammals ( Nicol 2015b)
  • Some completely nocturnal (Clemente et al. 2016)
• In hot climates, daily activity influenced by temperature (Clemente et al. 2016)
  • Least active in the afternoon, when daytime activity may be limited by the hottest time of day
• When resting, find shelter in burrows, in tree hollows at the base of trees, in clumps of grasses, in piles of leaves and bark, under rocks, or in caves (Nicol 2015a)

Seasonal variation in activity

• The short-beaked echidna shows some degree of seasonal inactivity throughout its range (Morrow and Nicol 2009)
• Daytime temperatures constrain activity during the summer (Clemente et al. 2016)
  • Nocturnal in warmer seasons and regions
  • Relatively more daytime activity in cooler seasons and habitats (e.g., alpine)
• More active in spring; spend more time digging and foraging (Clemente et al. 2016)
• Activity also influenced by changes in seasonal energy requirements, prey availability, and foraging–breeding priorities (Clemente et al. 2016)
• Also see Torpor and Hibernation

Time budgets

• Spend most of their time resting: approximately 80-85% in spring and summer (Clemente et al. 2016)
• Up to 12% of their time spent digging (Clemente et al. 2016)

Torpor

• Echidnas experience torpor (Nowack et al. 2016)
  • An animal in torpor lowers its body temperature, heart rate, and metabolism to greatly reduce its energy needs
  • Torpor is an adaptation used to survive periods of low food availability, temperature challenges, natural disasters, and population bottlenecks
• In echidnas, torpor can occur during any time of year (Augee et al. 2006)
• May help some echidnas survive natural disasters, such as wildfires (Nowack et al. 2016)
  • Some echidnas have been observed to increase torpor use after fire events
  • This strategy may help echidnas conserve energy after fires, when their subterranean prey likely move deeper underground
• Waking from torpor (the return of metabolic and circulatory functions) is much slower than awakening from sleep (Augee et al. 2006)

Hibernation

• Echidnas also experience hibernation (Augee et al. 2006)
  • Hibernation is a deep, extended form of torpor, where an animal’s body temperature approaches ambient temperatures
  • It includes brief periods of waking
  • Hibernation vs. torpor
• Advantages
  • Metabolism slows; short-beaked echidna is able to conserve energy, especially in the coldest parts of its range (Morrow and Nicol 2009)
    • May use less than 12% of the energy typically used when not hibernating (Augee et al. 2006)
  • Augee et al. (2006) propose that echidnas shift out of hibernation to gain reproductive advantages conferred by a warm body, endothermic state (see Augee et al. 2006, p. 110)
• Entry into hibernation
  • Echidna hibernation takes place in all climate zones, not just cold regions (Augee et al. 2006)
  • Echidnas in cold climates enter deep hibernation; those in milder climates only enter hibernation for short periods (Morrow et al. 2009)
    • Eastern Australia: long periods of hibernation
      • Tasmania: 3.5-7 months each year
    • Kangaroo Island: short periods of torpor, about 10 days at a time
  • Several weeks before hibernation, echidnas reduce food intake and activity; body temperature drops significantly (Nicol 2015a)
  • Echidnas hibernate in natural shelters; do not dig burrow (Nicol and Andersen 2007a; Nicol et al. 2011)
    • Hollow structures at the base of trees, log piles, under rocks, in piles of leaves, grass tussocks, loose soil
    • Provides a thermal buffer and protection from rain
• During hibernation
  • An echidna’s body temperature decreases to within 1°C (1.8°F) of the substrate/ground (Nicol and Andersen 2007a; Nicol 2015a)
    • Preferred body temperature: 8-10°C (46-50°F) (Nicol and Andersen 2007a)
    • Only maintain stable torpor when body temperature is below ~15-17°C (~59-62°F) (Morrow et al. 2009)
    • Lowest recorded body temperature for an echidna is 4.5°C (40°F)
  • Heart rate drops to as low as four beats per minute (bpm) (Augee et al. 2006)
    • Significantly lower than waking heart rate (resting, 50-68 bpm; active, 135-145 bpm)
  • Wake periodically
    • May move to a new location to thermoregulate (Nicol and Anderson 2007b), if burrow is damaged, or if overly harassed by males (Harris and Nicol 2014)
    • May stay in the same shelter, but adjust position or depth (Nicol and Andersen 2007a)
• Season of hibernation
  • For reproductive individuals, hibernation begins February-April (depending on location) and ends at the beginning of the breeding season in June-July (Augee et al. 2006; Morrow and Nicol 2009; Nicol 2015a)
    • During winter, echidnas are active and breeding (Augee et al. 2006)
  • In Tasmania, non-reproductive individuals hibernate an additional 2 months (up to 7 months of the year), September–October (Augee et al. 2006; Ruf and Geiser 2015)
• End of hibernation
  • Wake more frequently towards the end of hibernation (Augee et al. 2006)
  • Full waking occurs over eight hours (Augee et al. 2006)
  • Males end hibernation at least a month before reproductive females, possibly to allow time for sperm to develop or develop fat reserves before the mating season (Nicol and Andersen 2002; Augee et al. 2006; Nicol 2015a)

Home range

• Males maintain large home ranges for optimal access to nearby females (Sprent and Nicol 2012)
  • Home range size is, on average, twice as large as those of females (Nicol et al. 2011; Nicol 2015b)
    • 0.3-1.5 km²
    • Can cross his home range in a few hours
  • Large overlap with home ranges of females and other males (Nicol et al. 2011; Nicol 2015a)
  • Males maintain smaller home ranges during the non-mating season (Nicol et al. 2011; Sprent and Nicol 2012)
• Female home range size is influenced by resource availability (particularly shelter) and habitat quality, rather than searching for mates (Sprent and Nicol 2012; Nicol 2015b)
  • 0.15 km² to 0.70 km², depending on habitat quality (Nicol 2015b)
  • The home ranges of females only slightly overlap (Nicol 2015a)
  • Mothers use a large home range when young have grown enough to be left on their own in a nursery burrow (Rismiller and McKelvey 2009)
• The short-beaked echidna shows strong fidelity to its home range (Nicol et al. 2011; Nicol 2015a, except where noted)
  • Individuals likely spend most of their adult lives in the same home range, with occasional longer excursions
• Echidnas are solitary, but home ranges of individuals overlap; they do not defend territories (Augee et al. 2006)
• Likely use scent to mark the boundaries of their home ranges (Nicol 2015a)
• Outside of the mating season, short-beaked echidnas move around their home ranges over a period of days or weeks, searching for good foraging areas (Nicol 2015a)
  • No fixed shelter sites; take refuge opportunistically (Augee et al. 2006)
  • Total distance moved per day (Clemente et al. 2016)
    • 2.7-3.6 km (1.7-2.2 mi) per day in spring and summer
    • Farther than for other mammals of comparable size
    • Varies with season

Solitary, except during the mating period

(Nicol 2015b)

• Males seek out females during the mating season (winter) (Rismiller and McKelvey 2000)
• Some reports of female pairs or small all-male groups (e.g., Morrow et al. 2009)

Postures

• Detailed descriptions and illustrations are reported by Brattstrom (1973)
  • Examples
    • Investigative touch: bill used to explore an object
    • Submissive crawl: body is flattened, slowly crawls forward
    • Sleep: resting position with spines down
    • Defense: body round, with head tucked in and spines raised
    • Upside-down belly scratch: echidna rolls over on its back and scratches its belly with its claws
    • Earth-roll: echidna rolls over in a depression in the ground to dust bathe

Smell and scent marking

• Chemical signals are extremely important in the social and reproductive behavior of echidnas (Harris et al. 2014; Nicol 2015a)
• Secretions are produced from the cloaca and the spur located on the hind ankles (Harris et al. 2014)
  • More than 180 chemical compounds identified (Harris et al. 2012)
  • Composition varies among individuals; may be used in recognition of individuals, sex, relatedness, reproductive status, male-male competitive ability, mate quality, or other physiological status (Harris et al. 2012; Harris et al. 2014; Nicol 2015a)
• Echidnas scent-mark by dragging their cloacas along objects (Nicol 2015a)
• Non-breeding season
  • Echidnas are solitary; use scent and smell to communicate ‘at a distance’ (Nicol 2015a)
• Breeding season
  • Males are attracted to the scent of females and other mating echidnas (Nicol 2015a)
  • A male’s spur secretions change during the mating season (Nicol 2015a)
    • May be used by females to assess a mate
    • May be used in male-male competition
  • A female’s chemical profile does not change after mating or fertilization (Nicol 2015a)
    • Males unable to distinguish between unmated and pregnant females
    • May benefit females, but not well understood

Tactile communication

• Important during courtship and between mother and young; less important during other times of year (Rismiller and McKelvey 2000)
• Echidnas ‘bump’ each other (Brattstrom 1973)
  • During courtship
  • In managed care, when a dominant individual challenges a submissive individual

Vocalizations

• Few reported; considered by some not to vocalize (Nicol 2015a)
• Four types of sniffing noises were investigated by Brattstrom (1973); see Fig. 6 for sonogram image signatures
  • Investigative sniff: produced while searching for food
  • Fright sniff: produced when alarmed (e.g., when held by unfamiliar persons)
  • Jerk sniff: produced when an echidna quickly pulls itself into a defensive position
  • Social sniff: produced when approaching another echidna

Passive defense

• Find cover
  • At first detection of danger, echidnas run for close cover and hide in leaf litter, grasses, rocks, logs, and other shelter sites (Augee et al. 2006)
  • If pursued by predators on rocks, logs, etc., echidnas wedge their spines into cracks or gaps and place their more vulnerable head into the safety of a rock crevice (Nicol 2015a)
• If shelter cannot be reached (Augee et al. 2006; Nicol 2015a)
  • If the substrate allows, echidnas will dig into the ground and cover themselves with soil
    • If only able to partially cover themselves, their spines radiate outward for defense
    • Use claws to anchor themselves in the ground
  • Use spines to protect their vulnerable belly and head
    • If forced onto their back, tuck head and limbs into a ‘ball of spines’
• Young are kept hidden (Augee et al. 2006); see Nursery Burrows

Active defense

• When touched, move quickly, pushing their spines into the attacker (Nicol 2015a)
  • Spines do not detach when used for defense, unlike porcupines

Burrowing/digging

• Echidnas are powerful diggers (Nicol 2015a)
• Adaptive functions of digging (Augee et al. 2006; Nicol 2015a)
  • Experience more stable, less extreme temperatures underground
  • Avoid predators
  • Protect offspring with nursery burrows (Nicol 2015a)
    • See Parental Care
• Adaptations for digging
  • Broad pelvic girdle
  • Short, strong legs and muscles
  • Spoon/spatula-like claws
• Usually dig for less than 10 minutes at a time (Clemente et al. 2016)

Breathing underground

(Waugh 2006)

• Actively replenish air in spaces around their snout using “flushing movements”; this also helps to prevent soil particles from entering their nostrils
• Also breathe air that diffuses through the soil
• Due to a low metabolism, need less oxygen than other mammals

Behaviors to cope with thermal stress

• Response to heat
  • Sprawl out, lying flat on their stomach, limbs and snout outstretched to dissipate heat (Barker et al. 2016)
  • Blow bubbles out of their nose; the moisture cools the blood sinus and helps heat escape through their snout (Barker et al. 2016)
• Response to cold
  • Curl their body tightly around their feet and shiver; minimizes heat loss from the belly region (Barker et al. 2016)

Cooperative behavior

• In managed care, instances have been reported of echidnas ‘working together’ to gain access to food (Brattstrom 1973)

Improve soil health as “ecosystem engineers”

• Echidnas’ construction of foraging pits in soil promotes healthy microbial communities and ecosystem function (Eldridge and Mensinga 2007; Eldridge et al. 2016)
  • Organic matter (leaf litter, seeds) and moisture collect in these pits
  • Reduces soil surface temperatures and moisture loss
  • Enhances nutrient cycling
• Echidna activity may offset some of the soil degradation (e.g., increasing aridity) caused by grazing livestock (Eldridge et al. 2016)

Comparison to marsupials

• Monotremes (echidnas and platypus) and marsupials evolved to exploit different ecological niches (Phillips et al. 2009)
• No termite- or ant-eating marsupials exist (Nicol and Andersen 2007b)
  • Possibly because echidnas already filled this ecological niche in Australia

Relationship with humans

• Echidnas are usually camouflaged in a shelter site (Augee et al. 2006)
  • Not often seen by people, except while foraging or courting
• Most easily seen near roads or open pastures (Nicol 2015a)
• When touched, often hunch their shoulders and erect their spines; may spike someone not familiar with this behavior (Augee et al. 2006)

Walking

• Distinct rolling gait, unique among modern mammals (Nicol 2015a)
  • Locomotion is similar to that of both mammals and reptiles (Clemente et al. 2016)
  • Upper limb bones positioned at right angles to the body, similar to reptiles (Nicol 2015a)
• Move slowly due to low-energy diet and life history strategy (e.g., slow metabolism and low reproductive rates) (Nicol 2015a)
• Short stride (Clemente et al. 2016)
• Do not run; always have at least two points of contact with the ground (Clemente et al. 2016)

Swimming

• Able to swim; may flex snout upright to keep nostrils in the air, similar to a snorkel (Nicol 2015a)
• Swim to cool off during extreme heat (Nicol 2015a)
• Have been observed swimming in dams, across streams (Augee et al. 2006), and even short distances in the ocean on Kangaroo Island (Nicol 2015a)

To protect themselves in places with no cover, echidnas will dig into the ground and cover themselves with soil.

If unable to cover themselves completely, they will anchor in the ground with their spines radiating outward for defense.

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