The order Dasyuromorphia includes 23 genera and 71 species of carnivorous marsupials in three families: Dasyuridae (dasyurids), Myrmecobiidae (numbats), and Thylacinidae (thylacinids). Both Myrmecobiidae and Thylacinidae contain a single recent species, while Dasyuridae contains many species. The single species within Thylacinidae (Tasmanian wolf) is likely extinct. Dasyurids and thylacinids are more related to each other than they are to numbats.
In Australia, the oldest known members of the order Dasyuromorphia originated from south Queensland at least 55 million years ago. However, little is known about their evolution between the late Paleocene (55 mya) and the late Oligocene (about 24 mya). Fossil records are abundant from the early Miocene (23 to 16 mya), as the warm and wet greenhouse period resulted in high levels of diversity in rainforest communities. As rainfall decreased around 15 mya and Australia became cooler and drier, there was a steady and rapid increase in diversity of dasyuromorphs. Thereafter, with the arrival of humans and increased aridity, family-level diversity declined to the present level.
The order Dasyuromorphia is restricted to Australia, New Guinea, Tasmania, and some small nearby islands. During the Pleistocene era, land bridges connected the Australian mainland to New Guinea and Tasmania, allowing the exchange of faunas between these land masses. Modern distributions and genetic relationships of particular species serve as evidence of the interchange of fauna during this era. Because the Pleistocene was characterized by cooler temperatures, savanna and woodland species primarily migrated across the land bridges.
Biogeographic Regions: australian (Native )
Sexual Dimorphism: sexes alike; male larger
Other Physical Features: endothermic ; bilateral symmetry
Habitat Regions: temperate ; tropical ; terrestrial
Terrestrial Biomes: desert or dune ; savanna or grassland ; forest ; rainforest ; scrub forest ; mountains
Other Habitat Features: suburban ; agricultural
Dasyuomorphs are generalized predators that eat a wide range of invertebrate and vertebrate prey. Numbats are insectivorous, and one individual can consume 10,000 to 20,000 termites each day. Other families within Dasyuromorphia are carnivorous. They catch and eat both terrestrial and arboreal insects, including moths, beetles, and mosquitoes. Large species are also known to eat juvenile mice.
Vision and olfaction play key roles in hunting. Most dasyuromorph species possess vibrissae that help orient their attack toward prey; however, visual and tactile methods are also employed. Carnivorous marsupials bite or pin their prey with their forepaws. Bites are directed toward the anterior part of the body (head or neck) in order to assure capture. They are also known to shake and toss prey if they show resistance.
Foraging Behavior: stores or caches food
Primary Diet: carnivore (Eats terrestrial vertebrates, Insectivore , Scavenger ); omnivore
Before placental carnivores were introduced to Australia, New Guinea, and Tasmania, dasyuromorphs were the most prominent large predators. They still remain key predators, consuming a wide range of vertebrate and invertebrate prey. Numbats maintain stable termite populations by consuming an average of 10,000 to 20,000 individuals a day.
Dasyuromorphs coexist with other species in the order by partitioning resources in the structurally complex arid and forest environments. In the desert, dasyuromorphs forage above ground on clay soils, sand dunes, rocks, and grasslands. In the temperate and tropical forests, dasyuromorphs may be arboreal as well as terrestrial, searching for prey in the trees. Terrestrial dasyuromorphs search for food a few feet above the ground in shrubs and hollow trees. Larger dasyuromorphs, such as eastern quolls and Tasmanian devils, avoid competitors by foraging primarily in the trees.
Because dasyuromorphs include such a diverse array of species, they take on numerous ecosystem roles. Their most influential role, however, is predatory.
Ecosystem Impact: soil aeration
Dasyuromorph are vulnerable to reptilian, avian, and mammalian predators. They do not have any physical adaptations to deter predators and thus tend to minimize predation by foraging at night and under protective covering. Small dasyuromorphs are particularly vulnerable to introduced European red foxes. Domestic dogs, dingos, and domestic cats also prey upon dasyuromorphs.
- European red foxes, Vulpes vulpes
- Domestic dogs, Canis lupus familiaris
- Dingos, Canis lupus dingo
- Domestic cats, Felis sylvaticus
Life History and Behavior
Due to their nocturnal habits, dasyuromorphs have reduced their dependence on sight for communication and perception and have adapted olfactory and auditory mechanisms to compensate. Dasyuromorphs utilize chemical signals such as scent markers as a primary mode of communication. Commonly used chemical signals include urine dribble, cloacal drag, chin rub, and sternal rub. These are used to mark territory or as a status signal during breeding. Other social behaviors, such as mouth sniffing, naso-nasal sniffing, touching, and cloacal sniffing have been observed. Cloacal sniffing is especially important in male-female interactions.
Auditory communication is also common in dasyuromorphs. Vocalizations are mostly associated with defensive situations, such as nest defense, food defense, and threats but are also used in parent-offspring interactions as well as courtship and mating. Dasyuromorphs emit a chatter, tail rattle, foot tap, huff, or bark as an alarm mechanism when they feel threatened or in danger. Defensive vocalizations include hisses, huffs, grunts, growls and screams. When separated from their mother, young dasyuromorphs produce vocalizations that trigger mother retrieval behavior.
Dasyuromorphs also possess vibrissae that orient their attacks during predation. Males use tactile communication during mounting and copulation by grasping the neck and abdomen of the female.
Communication Channels: tactile ; acoustic ; chemical
Other Communication Modes: pheromones ; scent marks
Perception Channels: tactile ; acoustic ; chemical
The lifespan of dasyuromorphs varies greatly among the three families. Male numbats live up to 5 or 6 years in captivity, while females generally live longer. Little is known about Tasmanian wolves in the wild, and no information about their lifespan was recorded while they were still abundant. In captivity, however, they lived up to 12 years.
The lifespan of dasyurids is related to the amount of energy invested in early reproduction. Semelparous species, such as those in the genera Antechinus and Sminthopsis, invest heavily in one reproductive event and usually only live 1 to 2 years. Iteroparous species of dasyurids do not invest as much in early reproduction and live longer lives. For example, Tasmanian devils (iteroparous dasyurids) live an average of 8 years in the wild.
Although small dasyurids appear short lived, they actually have long lifespans compared to similarly sized eutherians. Whereas small dasyurids live 1 to 2 years, mice live only 4 to 6 months. The reasons behind these differences are still unknown but appear to be related to differences in metatherian and eutherian physiology.
Both male and female dasyuromorphs practice promiscuous mating during a relatively short but intense breeding season. Larger males are more successful at attracting females and fighting off competing males. During courtship, males display antagonistic behavior in which they chase the female. During copulation, the male grips the female’s neck with his teeth and clasps her body with his forepaws to facilitate mounting. This continues throughout copulation, which lasts several hours. While copulating, males in the genus Antechinus can turn their bodies 180 degrees to ward off other males. After mating, males may guard a female for up to 12 hours to prevent other males from mating with her. Male Tasmanian devils are particularly aggressive during mate guarding and do not allow the female to leave her den for food or water for days. Occasionally females are able to escape these aggressive males but usually not without injury.
Females release pheromones to signal their receptivity to mate. They solicit males they find attractive and ward off other males. Females have long periods of behavioral estrous which allow them to mate with several males unless particularly aggressive males prohibit their ability to do so. Thus, multiple paternity as a result of sperm competition is often observed. For example, it is not uncommon for a litter of four Tasmanian devils to have four different fathers. Dasyurids (Dasyuridae) exhibit a unique form of sperm competition, and, other than bats, they are the only mammals in which females can store competing sperm within their reproductive tracts prior to ovulation.
Mating System: polygynandrous (promiscuous)
Dasyuromorphs are either semelparous or iteroparous. Semelparity is very rare in mammals, having arisen only in dasyurids and didelphids. Semelparous dasyuromorphs, such as antechinuses, generally live in environments with predictable seasonal patterns of food abundance. It is thus advantageous to align reproductive patterns with seasonal variation in resource abundance. The mating season occurs in the winter when resources are scarce, and consequently young are born when resources are most abundant. Because seasonal patterns are so predictable, it not risky to dedicate all of their reproductive efforts into one brief mating season.
Males devote most of their energy to one big reproductive effort, and as a result have high concentrations of stress hormones in their blood. This inhibits inflammatory and immune responses and eventually kills the exhausted males. Females may survive for a second breeding season but almost never survive for a third. Semelparous dasyuromorphs are characterized by prolonged copulation, large testes size, male sexual dimorphism, mate guarding, long behavioral estrous of females, sperm storage in female reproductive tracts, high population densities, and sperm competition.
Iteroparous dasyuromorphs, on the other hand, reside in less restricted, less predictable environments. Therefore, it is risky to invest all of their energy into one reproductive effort when resource levels are so unpredictable. During the breeding season, Northern quolls exhibit normal levels of stress hormones and have larger body sizes and tail fat stores that help them survive to the next breeding season. Iteroparous dasyuromorphs do not display any of the identifying characteristics of semelparous dasyuromorphs. Additional reasons for semelparity in some species and iteroparity in others are not well understood.
Key Reproductive Features: semelparous ; iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous ; sperm-storing ; delayed fertilization
After the brief mating season, male dasyuromorphs leave females with all parental responsibilities. In semelparous species, such as antechinuses, males die before their offspring are born.
Gestation time varies greatly with body size, as does time spent in the mother's pouch. After leaving the pouch permanently, young are carried into well-hidden dens. Dens are lined with vegetation for protection and warmth and are located in underground burrows, caves or hollow logs. As young near weaning, mothers take more frequent trips outside of the den. When mothers begin to sleep away from their young, male offspring disperse from the den. Males move away from their mother's home range while females remain in their mother’s home range for life.
During lactation, many dasyuromorph mothers are biased towards their male offspring and provide them with more nutrient-rich milk. Because larger males are more successful in attracting mates and reproducing, it is advantageous for mothers produce larger males that have a better chances of passing on her genes.
Parental Investment: altricial ; female parental care ; pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female); post-independence association with parents; inherits maternal/paternal territory
Molecular Biology and Genetics
Statistics of barcoding coverage
Specimens with Sequences:38
Specimens with Barcodes:38
Species With Barcodes:11
Dasyuromorphs did not cope well with the arrival of Europeans to Australia more than a century ago. On the IUCN red list, six species are listed as endangered, one species, Sminthopsis aitkeni, as critically endangered and one species, Tasmanian wolves, as extinct. Currently, the most prominent threat to dasyuromorphs is the rapidly expanding human population. Clearing land for agriculture, draining and salination of wetlands, and grazing by livestock both destroys and fragments habitat. Introduced placental carnivores like red foxes have decimated populations by preying on smaller dasyuromorphs and competing with larger ones. Additionally, climate change has resulted in drought and uncontrollable fire regimes that alter their habitat. Because they rely on a large number of omnivorous and herbivorous prey to survive, dasyuromorphs are vulnerable to small changes in their habitat.
If habitat destruction and fragmentation continues, other dasyuromorph species may face the same fate as Tasmanian wolves, the only large carnivores to go extinct in recent times. The last confirmed sighting of a Tasmanian wolf in the wild was in 1930, and in 1936 the last captive animal died. There are claims of recent sightings and tracks of Tasmanian wolves, but proof of their continued existence is lacking.
Today, efforts are being made to remove rabbit populations from known dasyuromorph habitats. Rabbits not only damage the habitat of dasyuromorphs but also attract predators like dingos and red foxes. In the 1800s, a government bounty led to the death of over 2,000 Tasmanian wolves because of their predation on sheep and other livestock. Today, nearly all dasyuromorphs are protected from hunting and over-harvesting under the laws of the states and territories of Australia.
Relevance to Humans and Ecosystems
Large dasyuromorphs have a reputation for killing livestock, such as sheep, but they rarely kill prey this large. However, domestic eastern quolls, Tasmanian devils, and phascolages often prey on domestic poultry. Because of this, farmers view these large dasyuromorphs as pests. Tasmanian wolves were large enough to successfully prey on sheep, and retaliation from angry farmers may have contributed to their extinction.
Dasyuromorphs, like other marsupials, are held in great regard by the native Australian Aborigines. Cultural practices such as dreaming stories, myths, rituals and totems were devoted to dasyuromorphs, especially the larger species. Australian Aborigines have hunted many species of dasyuromorphs as a source of food for thousands of years. On their arrival, European settlers also hunted dasyuromorphs for food.
Some species of dasyuromorphs are beneficial because they deter agricultural and forest pests, insects, and rodents. Eastern quolls often live on farmland and aid farmers by consuming pasture grubs, mice, and insects that invade human crops.
Positive Impacts: food ; ecotourism ; controls pest population
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