Dasyuromorphia

The dasiuromorphs (Dasyuromorphia) are an order of marsupial mammals endemic to the Australian continent.

The order contains four families: one with only one living species (the numbat), two with only extinct species (including the thylacine and Malleodectes), and one, the Dasyuridae, with 73 extant species.

History

The origin of the dasiuromorphs is in the Upper Oligocene, with the Thylacinidae family being the first to differentiate. Only one species in this family, the marsupial wolf (Thylacinus cynocephalus) has survived into historic times, although it was declared extinct in the first half of the century XX. The other two known species of thylacinids disappeared in the Pleistocene.

The loss of hegemony of the thylacinids took place during the late Miocene, coinciding with the great diversification of the dasiurids, which appeared during the Middle Miocene.

None of the groups with presently living species arose before the Pliocene, but all fossils from the Pleistocene still know species closely related to living specimens.

As regards the myrmecobids, the oldest known fossil data come from the Pleistocene.

Habitat

These animals inhabit Australia, Tasmania, New Guinea and nearby islands, colonizing a wide variety of ecosystems in this geographic region. Most of them have terrestrial habits, although some species are exclusively arboreal.

Australasian carnivorous marsupials live in many different habitats, from the rainforest to the desert. Each species has adaptations that allow it to live in its particular environment. For example, the numbat has claws that are used to scratch the ground and dig up termites in the forest where it lives. The Spot-tailed Quoll has special ridges on the bottom of its feet and sharp claws that help it climb large trees.

Many of Australasian carnivorous marsupials live in habitats where it can be very hot or very cold. Different species have different ways of protecting themselves from these extreme temperatures. Some species, such as the numbat, dig underground burrows that they line with dead leaves and other plant parts to insulate themselves. Other species are capable of reducing their body temperature on purpose. This is called torpor, and it reduces the amount of energy an animal needs to live when it is too cold or exposed to other environmental stresses, such as food shortages.

Food

Feeding habits vary from the diet exclusively based on termites and other colonial insects of Myrmecobius fasciatus to the exclusively carnivorous of Thylacinus cynocephalus.

Carnivorous Australasian marsupials eat meat and insects. What each species eats depends on its size, its habitat, and the type of adaptations it has for hunting. The smaller species usually eat insects, and the larger ones other animals, although they sometimes eat insects as well. Many of the larger Australasian carnivorous marsupials are able to chew and eat whole animals, including bones and skin. The numbat lives in the forest and eats termites that it digs up from underground with its sharp claws or that it finds under dead branches that it pushes with its pointed snout. The Tasmanian devil eats many types of meat, and has been reported to eat animals as large as wallabies.

Features

As varied as the ecological niches they occupy, is the appearance and anatomical characteristics of the animals classified in the order, presenting only some features common to all species such as having a poorly developed pouch that, in some species, only it is evident in times of breeding, not presenting syndactyly phenomena and a polyprotodont dental formula.

Dasyurus maculatus.

Unlike herbivores, which tend to be highly specialized in certain ecological niches and highly diversified in form, carnivores tend to be very similar to each other, especially in terms of their external form. Just like carnivores in the northern hemisphere, such as cats, mongooses, foxes, and weasels, are much more similar in structure than, for example, camels, goats, pigs, and giraffes, so are marsupial predators. they are forced to maintain similar forms in general use—forms that mirror those of placental carnivores. The names given to them by early European settlers reflect this: the thylacine was called the "Tasmanian tiger" or "Tasmanian wolves", quolls were called "native cats" or "native foxes", etc.

The main specialization among marsupial predators is that of size: before the enormous environmental changes that occurred with the arrival of humans around 50,000 years ago, there were several large carnivores, none of them members of the Dasyuromorphia and all of them already extinct. Those that survived into historic times ranged from the wolf-sized thylacine to the tiny long-tailed planigale, which at 4 to 6 grams is less than half the size of a mouse. Most, however, tend towards the lower end of the size scale, usually between about 15 or 20 grams and about 2 kilograms, or from the size of a house mouse to the size of a small house cat.

Behavior

Australasian carnivorous marsupials spend most of their time foraging. Each species has different ways of finding prey, from burrowing for termites, climbing trees and raiding opossum nests at night, to feeding on the carcasses of already dead animals.

Most Australasian carnivorous marsupials are relatively short-lived. Females often mate with more than one male, and in many species, young born in the same litter have different fathers. Some species of this order only mate once in their lifetime. They usually die soon after reproducing, having used all their energy in a sudden burst of activity necessary for successful mating. Antechinus, which are broad-legged marsupial mice, mate in this manner. The female lives long enough to raise her young until they can live on their own, but the male usually dies before his young are mature.

Australasian carnivorous marsupials, like all marsupials, have very short gestations, some lasting only a few days. They give birth to immature young that are usually blind and hairless, and are always unable to survive on their own. In most cases, the young are inserted into the mother's pouch, which contains milk teats, and are carried with her wherever she goes. Some species have young that crawl onto the external teats, or teats, of the mother. They cling to them and are carried wherever the mother goes, protected only by the hairs on her belly. Many do not survive to maturity.

The time the young spend growing outside the mother's womb, or uterus, depends on the species. It can be as short as a few weeks or as long as many months. In most species, once the young have grown large enough to fend for themselves, they spend a short time in the mother's nest or burrow, wandering off each day to find food, until finally leaving. the nest forever.