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Gilbert’s Potoroo (Potorous gilbertii) was a ratlike marsupial fungivore which lived in great numbers throughout south-west Australia—particularly around King George Sound. The animals were discovered to science by the great naturalist George Gilbert in 1840. Unfortunately the potoroo proved to be extremely vulnerable to introduced predators such as foxes and dingoes. After an exhaustive search in the 1970s failed to find any living specimens of the creature (which had not been seen in decades) the unlucky mammals were deemed extinct, and thus Gilbert’s potoroo vanished forever from the—[needle comes off of sad record]—wait! actually this strange rodent-like/kangaroo-like creature was rediscovered in 1994.
After nearly two decades during which time the potoroos were presumed dead, a small population was found living in a remote and inaccessible scrubland beside Two Peoples Bay in Western Australia. The area was proclaimed a nature preserve and humankind leapt into action to save the beleaguered potoroo.
Yet, it has not been easy to relaunch the peculiar animal. The creatures live on truffle-like fungi, which they dig up with their three toed paws (each digit has a sharpened digging claw). The male potoroos are susceptible to balanoposthitis, a bacterial disease which disfigures the genitals with inflammation and leaves the creatures unable to reproduce. Also the animals seem to be extremely sensitive to cryptococcosis, a dangerous fungal disease which can lead to coughing and respiratory failure.
Fortunately, patient zookeepers, rangers, and volunteers have been working to help Gilbert’s potoroo overcome these alarming hurdles. The world population now numbers nearly 70—but the peculiar marsupial digger remains one of the planet’s most endangered mammals.
This is the common spotted cuscus (Spilocuscus maculatus) an arboreal marsupial from the Cape York region of Australia and New Guinea. The furtive nocturnal animal is seldom seen by humans, but it is quite successful and has spread through Papua New Guinea, Irian Jaya, and the Cape York Peninsula. The common spotted cuscus is a species of possums, a group of approximately 70 species of arboreal marsupials which are native to Australia, New Guinea, and Sulawesi. The Indo-Australian possums are analogous in lifestyle to the opossums of the Americas. Because of their furtive lifestyles most possums and opossums are unknown except to specialist zoologists (with the exception of the incredibly successful Virginia opossum).
The common spotted cuscus is about the size of a housecat and weighs from 1.5 to 6 kilograms (3.3 to 13.2 pounds). The name is something of a sexist misnomer—among adults, only the males have blotchy spots on their grey/brown pelts. The spotted cuscus has numerous specialized features for its tree-dwelling lifestyle including nimble clawed digits on both its hands and feet, a prehensile tail, and strongly binocular vision. Its paws are particularly adapted for grabbing trees: the “palms” of its hands and feet are bare with special striations to give the animal a nimble clinging grip. Both its hands and feet have opposable grips—in fact the first and second digits of a cuscus’ forefoot are opposable to the other three digits so it can hold on to limbs with a deathlock. The cuscus has few natural enemies other than pythons and predatory birds, but if it is threatened it will bark aggressively and attack with its forepaws.
The spotted cuscus mostly lives on a wide variety of plant products—leaves, fruits, seeds, and nectar, however, given the opportunity, the cuscus also eats small animals and eggs. A mother cuscus usually has only one infant, which she raises in her pouch till it is big enough to ride on her back (although occasional larger litters of up to three are known).
The common spotted cuscus lives in dense tropical forests and mangroves. It has a lifespan of up to eleven years. So far the common spotted cuscus has not been threatened by habitat loss and indeed remains common (although increased logging in New Guinea may put pressure on some populations).
The quokka is a small macropod. Hmm, maybe I better explain that a bit: macropods are browsing/grazing marsupials which use their long hind legs and muscular tails to aid locomotion —the most famous exemplars are kangaroos and wallabies. The quokka (Setonix brachyurus) is a small-kangaroo-like mammal about the size of a domestic cat (2.5 to 5 kilograms (5.5 to 11.0 pounds)). They are mainly nocturnal and live on some small islands along the coast of southwestern Australia, although there is a small dwindling population on the mainland.
Just like that one kid in grade school, Quokkas have “a stocky build, rounded ears, and a short, broad head.” Early European explorers to Australia were perplexed by the quokka and wrote of them as cats or giant rats. Quokkas can climb trees and shrubs (which they graze on) and they live in semi-arid scrubland, dry forests, and in gardens and lawns.
Quokkas have dwindled greatly in their natural range due to habitat loss and invasive predators like cats, dogs, foxes, and dingoes. Somewhat sadly, quokkas have no natural fear of humans and will approach quite closely, particularly on Rottnest Island, where the highest population concentration is found. This leads to all sorts of unpleasant incidents–for humans are very dangerous indeed–so the local authorities have levied fines for touching or handling the animals (the fines are charged to the humans—the quokkas having thus far failed to master finance).
Although their plain brown fur and giant pupils keep them from top-tier internet fame, quokkas are pretty adorable. They look like a cross between kangaroos, squirrels, and koalas (which kind of also describes their lifestyle). Their lamentable fearlessness also leads to many great photos!
Everybody knows about the Easter Bilby—the magical marsupial who brings Easter eggs and candy treats to the good children of Australia (who are scarred by years of pestilential rabbit hordes)—but what does that have to do with Christmas week? Well, this year bilbies are taking over Christmas as well as Easter. Taronga Zoo (the city Zoo of Sydney Australia) is celebrating the birth of the zoo’s first-ever bilby joeys! Although the bilbies were actually “born” 10 weeks ago, they are only just now emerging from their mother’s pouch. The gestation period for the bilby is a mere two weeks, but when they are born they are still a bit underdone so they linger in the mother’s protected pouch for 75 days! The mother of these adorable little scamps is named Yajala. She moved to Sydney in order to pursue romance with George, the resident male bilby. Since their mother is still extremely secretive and protective of her new little ones, it is unclear what gender the two babies are. Their birth is exceedingly good news for bilbies which are terribly endangered by habitat loss and invasive predatory edentates. The bilbies are all greater bilbies (Macrotis lagotis), which is the last living species of the family Thylacomyidae. Aren’t they adorable?
Monito del monte (Dromiciops gliroides) is a tiny arboreal marsupial native to the temperate rainforests of Chile and Argentina. The name “Monito del monte” means “little monkey of the mountain” and although the tiny marsupials are not even remotely related to primates, they are clever and deft. During the cold winter months the animals hibernate in little ball-like nests which they build out of waterproof leaves and line with moss. Like the more familiar marsupials of Australia, the females have pouches where they nurse their litters of up to four offspring.
The adult animals prey on small invertebrates which live in the trees but they also supplement their diets with fruits and seeds. A particular species of Loranthacous mistletoe (Tristerix corymbosus) has evolved in conjunction with the monito del monte and relies entirely on the animal to spread its seeds. This is noteworthy because “scientists speculate that the coevolution of these two species could have begun 60–70 million years ago.” The monito del monte is not some rodentlike offshoot of the marsupial line, it is a close analog (and direct descendent) of the basal line from which all marsupials spring.
In fact, like something out of a gothic novel, the monito del monte is the only species of the sole genus of the last family of the exceedingly ancient order Microbiotheria. During the dawn of the dinosaurs, South America, Antarctica, and Australia were amalgamated together as a supercontinent Gondwana. The offspring of the original marsupials spread from South America, across Antarctica, to Australia, but then the continents drifted away from each other and evolution took a different direction in each ecoysytem. The monito del monte remained in the same sort of forest as its ancestors and changed least over the years.
Speaking of which, the Valdivian temperate rain forests where the monito del monte lives today are themselves a remnant of the great forests of Gonwana. The trees and plants which live there now are most closely related to the living plants of Australia, New Zealand, & New Caledonia, but they are closer still to the fossilized forests which lie beneath the glaciers of Antarctica. The Valdivian forest is the closest thing surviving to the great forests which once covered the iced over southern continent.
The ancestors of the monita del monte—and of all other marsupials—originated in South America and spread through the Antarctic forests to Australia before the continents drifted apart during the Cretaceous. When the continent broke from Australia and drifted south into the prison of the circumpolar current during the Eocene, the forests died and Antarctica became an otherworldly landscape of ice. Yet if you wish to know what the sweeping temperate forests of Antarctica were like you can visit Chile and watch the most ancient marsupial among the tree ferns and araucaria trees of the Valdivian forest.
Bilbies are blue-gray in color and they grow to about 29–55 centimetres (11–22 in) in length and 3.5 kgs (8 pounds) in weight. They use their sharp claws to unearth a wide diet of insects, arthropods, larvae, small animals, seeds, fungi, bulbs, and fruit. Bilbies rarely drink—they get all the moisture they need from their food.
But wait a minute! Fossorial Marsupials? Arid scrubland? Short gestation? What does any of this have to do with Easter? Well, due to a century of continent-wide ecological disaster caused by a plague of invasive bunnies, Australians hate rabbits with a burning passion (although of course this was not actually the fault of rabbits but was yet another mistake made by nature’s most problematic children). The Easter bunny is not as popular in Australia as elsewhere—giving an Australian child a candy Easter bunny would be like giving a New Yorker a chocolate Easter rat.
Fortunately Bilbies have boldly stepped in to the Easter bunny’s role. In a land where rabbits are regarded as an abomination, the long eared bilby has become the mascot of Easter. Throughout Australia, bilby-shaped confections and related merchandise are sold as an alternative to Easter bunnies. Additionally a number of children’s books have popularized the Easter bilby who seems to have a touch of animist aboriginal magic. For example a passage from Burra Nimu, the Easter Bilby, describes the dyeing of Easter eggs like a dreamtime myth of the desert:
“[The bilby] knew that eggs meant the start of new life and new hope, so he made his especially beautiful. He painted rich red eggs, the colour of the hot desert earth, and splashed them with bright sparkles, because the desert is full of life…Next, he painted soft green eggs and sprinkled them with the colours of the wild flowers he had once seen, soon after the water fell from the sky.
I always liked the Easter bunny (and don’t get me wrong, I’m still thankful for the baskets of candy and toys he left) but it seems appropriate that his role has been usurped in Australia. By taking over the function of a minor holiday deity, bilbies have gained new prominence as one of the symbols of Australian conservation. Enjoy Easter (or Passover or Mawlid-al-Nabi) and enjoy this little bilbie gallery I have put together!
I have always been fascinated by saber-toothed animals. Only a few saber toothed creatures remain in today’s world (like the estimable walruses and a few tiny saber-toothed deer) but in fearsome ages past, the design was widespread. Most readers are probably familiar with the smilodons, the magnificent saber-toothed cats which hunted the megafauna of Pleistocene North and South America, however the story of the saber-toothed cats intersects the story of another giant saber-toothed predator which was nearly as fearsome and even stranger. Thylacosmilus was a genus of saber toothed marsupial predators which ruled South America during the Miocene and Pliocene. Like the smilodons, Thylacosmilidae were large, agile predators which used their long fangs to slash the throats of huge prey. Unlike Smilodons, Thylacosmilidae were marsupials which gave birth to a tiny helpless larva which they then nurtured in a pouch.
The prominent teeth of Thylacosmilus were a result of convergent evolution and the creatures did not share any direct ancestors with cats since the divergence of placental and marsupial mammals (deep in the depths of the Mesozoic). Thylacosmilus’ teeth were also different in that they continuously grew throughout the animal’s life. The teeth were probably worn down as the predators gnawed on bones. Additionally Thylacosmilidae possessed scabbard-like bone flanges built into its lower jaw to protect its teeth (a feature missing entirely from Smilodons). Who knows what sort of noises Thylacosmilidae made with these peculiarly shaped mouths? For millions of years Thylacosmilidae lorded over the strange mammals of South America. The glyptodonts (and possibly other armadillos) developed their armor to ward off the mighty beasts. However the fickle play of tectonics undid the mighty killers.

Thylacosmilidae and Smilodons were not closely related (click on this picture to visit "Understanding Evolution" an excellent site where I found this helpful image)
In the beginning of the Pliocene, a land bridge joined North America and South America and suddenly the true cats arrived on what had been an island continent. As the climate dried out, Smilodons competed directly with Thylacosmilidae. Strange new herbivores appeared to displace the old prey animals. The Great American Interchange of long sundered mammalian lineages proved too much for the saber toothed marsupials. Thylacosmilidae were giant and fierce but they were no match for invasive cats.
To borrow a page from the timeless style of Sesame Street, this week Ferrebeekeeper is brought to you by the Roman letter Q. Each post will concern a topic which begins with that rare letter. So quench your thirst with quinine water and wrap up in a quaint quilt. There is a reason that the letter Q is worth 10 points in scrabble but I think we can find 5 relevant topics that are not too quixotic (also I’m going to stop using extra q words for effect immediately—please don’t stop reading).
For the first q-themed post, we must travel to the ancient arid continent of Australia. For reasons of geology and tectonics, Australia has been a wallflower in the great continental ballet and has been isolated for the last 40 million years. Thanks to this geographic seclusion, the animals of Australia are much different than the creatures which flourish elsewhere, and Austalia’s mammals are dominated by marsupials like the kangaroos, the wombats, the koalas, and the bandicoots. All of those creatures are herbivores, but there are insectivorous marsupials (like the numbat) and there are marsupial carnivores which prey on the others. Some of the larger orders of marsupial predators have died off as Australia dried out, but a major order of predators remain–the catlike quolls.
Quolls (genus Dasyurus) are solitary, nocturnal mammals which seek shelter in their burrows and dens by day and hunt birds, amphibians, reptiles, and small mammals at night. They are agile all-terrain creatures capable of swiftly moving across the forest floor or through the forest canopy. Quolls kill their prey with a bite to the neck where it joins the head. In addition to being predators, they also scavenge for carrion and they can sometimes be found by picnic areas and rubbish dumps. There are six species of quolls which range in size from 350 grams (12 ounces) to 3.5 kilograms (8 pounds). Four species are located across the Australian mainland while one species inhabits New Zealand. One outlier species, the Bronze Quoll (Dasyurus Spartacus) lives in the savannah of New Guinea. The animals all share a characteristic spotted fur coat and a similar lifestyle. The closest relatives of quolls are the formidable Tasmanian devils (the largest extant marsupial carnivores) and the superficially weasel-like mulgaras.
Unfortunately, quolls are not doing well. Feral cats, dogs, and foxes are much more deft predators and are outcompeting the quolls or eating them outright (although the quolls do get some free meals from the invasive wave of rabbits and rats which have swept Australia). Additionally the quolls are falling victim to an even stranger invasive species. The Cane Toad (Bufo marinus) is a toxic South American toad which was brought to Australia in order to control agricultural pests. The toads secrete a powerful toxin which is potent enough to kill a human (some people ingest cane toad secretions in order to experience the hallucinogenic effects). Cane toads resemble some of the natural amphibian prey species of quolls and the spotted predators eat them voraciously—only to fall sick and die. In order to save the unlucky quolls, a project is afoot to train the predators not to eat cane toads. Wildlife researchers have been dropping small sausages made of cane toad from airplane in quoll habitats. It is hoped that quolls will eat the sausages and become violently sick (but not fatally so). Having had a miserable bad trip, the quolls will then presumably forbear from eating further cane toad flesh.
The largest marsupial known to science is the now extinct diprotodon. Also known as the giant wombat or the rhinoceros wombat, this mighty marsupial grazer stood nearly 2 meters (6 feet) tall and stretched 3 metres (9.8 feet) from nose to tail. The animals flourished throughout much of the Pleistocene. From 1.6 million years ago until about 40,000 years ago, herds of Diprotodonts roamed across all of Australia. These giant wombats were indeed closely related to today’s wombats and koalas: jointly such creatures make up the Vombatiforme suborder Considering how formidable the bulldozer-like living wombat is, diprotodons must have indeed been like rhinoceroses and they probably occupied a similar top spot in the Australian web of life.
Unfortunately, like a substantial portion of Australia’s mega-fauna, the giant wombats disappeared shortly after humankind reached the island continent. The creatures apparently were destroyed by some combination of climate change, human hunting, and slash-and-burn land management. Aboriginal dreamtime lore makes extensive mention of a mighty furred beast called the bunyip–which has led anthropologists and paleontologists to speculate that the diprotodon has lived on in oral tradition for tens of thousands of years.
The numbat (Myrmecobius fasciatus) is a small marsupial termite eater with lovely banded fur and an incredibly long sticky tongue. These animals are also known as walpurtis. Although the creature’s claws are not strong enough to break into termite mounds, the numbat digs where termites are traveling between their mounds and their feeding grounds. It then rapidly gathers them up with its amazing tongue. Numbats are at most 45 centimeters long (about 18 inches) half of which is bushy tail. Large individuals only weigh half a kilogram (a bit more than a pound). They were discovered to Europeans in 1831 by an English naturalist who was delighted by their delicate appearance.
Numbats are not closely related to other marsupials and it is speculated that their nearest relative might be the thylacine, a marsupial predator extinct since 1936. Although once widespread, numbats had a near brush with extinction themselves: their population dipped below 1,000 during the late seventies. Foxes (which were introduced to provide sport to landowners before becoming deadly invaders) and other introduced predators were to blame for the near obliteration of the species. Even though they are now protected, numbats remain extremely endangered. Today they can only be found in miniscule protected habitats and in zoos. Speaking of zoos, the zooborns website features this ridiculously endearing clip of Australian zookeepers hand-rearing baby numbats.