I wonder if… you will see a koala bear

Dear J-E Missy/Kalli,

My last blog post mentioned two of my favorite new animals that I’ve seen in Tasmania: the duck-billed platypus, and MacLeay’s Swallowtail. Both of those animals are native to both Tasmania and mainland Australia, meaning they evolved here over millions of years.

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Nick was wondering “if you will see a koala bear.” Koalas do live in Australia, but only on the mainland. Since Tasmania is a smaller island to the south, and you have to either fly or take a boat and cross 150 miles of choppy water from mainland Australia, koalas would have to be champion swimmers to get here by themselves. People often “introduce” animals and plants to places far away where they can’t bring themselves. Sometimes those introduced species can become a problem, because they don’t stay in balance with the rest of the living things in the place that they are introduced to. Because of the problems it has had with introduced species, Australia is now very careful about what it lets people bring into the country, and to islands like Tasmania. When you fly here, there are specially trained sniffer dogs in the airport that check you and your luggage out to make sure you haven’t brought in any kind of fruits, vegetables, animals, or any products made from them that could be carrying pest species.

I don’t know if anyone has ever tried to introduce the koala bear to the wild in Tasmania, but there is another introduced animal whose name sounds kind of similar: the kookaburra. It is a big bird that is known for its incredibly loud “laugh.” Actually, to me it sounds more like a combination of all of the loud jungle noises you could possibly imagine. Kookaburras live in family groups, so there are often several of them whooping it up at once.

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Laughing kookaburra (Dacelo novaeguinea)

Laughing kookaburras are native to eastern mainland Australia, but people brought them to other parts of the country, where they are now considered a pest. They nest in holes where parrots and owls usually would, and will eat baby birds and other little animals that can’t hide well or escape from them. Watching them in the old gum trees is entertaining, but when they show up, other birds leave. Last week I was hiking through a rainforest where there should have been great habitat for birds, but the only bird I saw or heard for hours was a kookaburra.

So, to answer your question, I won’t see a koala in Tasmania unless I go to a zoo. But I have seen its cousin, the native wombat, which looks like a small bear and has a face similar to a koala’s. It moves faster than a koala, though, so I sneak and spy on it when it is looking for food at dusk.

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What native and introduced animals do you think live in Maryland?

 

Mammalia

Here at Windgrove, Peter has created the Gaia Walk – a 1.2 km trail that winds through land and time, each meter representing 500,000 years of evolutionary history. There are markers showing significant events, along with plaques depicting life in that era. His objective is to help walkers of the trail feel time unfolding, to embody the distance that has brought life to the present. If you walk the trail backwards from the present, humans show up almost immediately, after only 3-4 meters.  The first mammals are a good distance beyond that, in the Triassic period. Peter’s Forest Bench is a good place to contemplate where we mammals sit in this span of time.moosebench

Tasmania offers a unique window into evolutionary time, and what it has meant for mammals and their divergence. When this mammal takes a morning walk down the Gaia trail to the beach, I invariably startle large creatures who thump loudly and then vanish with a quick rustle into the brush.Usually this happens before they are even visible, but face-to-face encounters with wallabies and pademelons (a smaller version of a wallaby) have the same result. The thump is akin to a deer’s warning stomp or snort. With the exception of their hindquarters and tail, wallabies look, act, and eat very much like deer, pruning shrubs into topiary shapes and grazing grasses down to a few millimeters, leaving scat everywhere. Wombats show up at times too, looking like a cross between an overgrown groundhog and a bear cub with a cute koala nose. They dig huge burrows and tunnels that would be the envy of any groundhog, and when they spot you, they scoot away with a funny hopping gait. “A wombat eats, roots, and leaves” is true with or without punctuation. Brush-tailed possums are an abundant nocturnal marsupial, with thick fur and a winsome expression. They are also the scourge of Peter’s gardens, being acrobatic and incredibly persistent, necessitating multiple layers of fencing and baffles to keep them at bay.

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pademelon

 

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red-necked wallaby

 

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wombat

 

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brush-tailed possum

I finally managed to see Tasmanian devils, also marsupials, by visiting a sanctuary down the road (the “Unzoo”). It acts as a rehabilitation center for animals afflicted with or at risk of contracting the viral cancer that has caused recent decline in their population. Since they are mostly nocturnal, I have yet to see most of the other marsupials that live here, like bandicoot, betong, potoroo, or quoll. The names alone are intriguing, but I am also fascinated by the evolutionary divergence of marsupials from placental mammals. Here, the only native placental mammals are rodents, bats, and sea mammals.  How did North America end up with so many placental mammals but just one marsupial – the opossum? What made it so successful to give birth to tiny, undeveloped young and then nurture them in a pouch, as opposed to keeping them inside and attached to the mother’s body until they have more equipment, yet are still fully dependent on milk and protection? It’s easy for those of us more familiar with the latter mode of child-rearing to consider marsupials a strange and less significant sidetrack of evolution, but it’s hard to argue with their obvious success here.

 

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juvenile Tasmanian devils

 

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adult Tasmanian devil

 

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Australian fur seals

 

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common dolphin

 

And then of course there are what seem the ultimate bizarre mammals: the monotremes, the duck-billed platypus and the echidna, which split off the mammal trunk well before marsupials and placental mammals diverged. They produce young in soft-shelled eggs and feed them milk when they hatch by way of specialized mammary tissue. I’m still hoping to see a platypus when we travel north next week, but echidnas live at Windgrove. We’ve come upon these spiny anteaters a few times now, lumbering along poking their long, snorkel-like noses into loose dirt, under sticks, anywhere that their tongues can snag a few insects with sticky saliva. They have poor eyesight but keen hearing, so the click of my camera shutter usually makes them freeze and tuck themselves into a ball of quills. One alarmed echidna scooted over to a patch of tall grass and immediately began digging itself in at the base of the plant. With backwards facing hind feet and strong front claws, it was able to excavate a deep pit in no time, and soon only its prickly back was exposed. I was not tempted to dislodge it. If the quills weren’t deterrent enough, the males also have a venomous claw on each hind leg.

 

 

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short-beaked echidna

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There is another group of mammals – the ones like rabbits and feral cats introduced by humans – that has had a profound and often devastating effect on Australian ecosystems, but I will save discussing them for another time. Meanwhile, even though I know it’s futile, I can’t help hoping that I will round a corner on the trail one day to discover a dog-like marsupial with a striped back and wide jaws devouring a rabbit. It’s been officially extinct for almost a century now, but there are those who believe that the Thylacine, the Tasmanian tiger, still roams in wild places here. Windgrove seems like a perfect spot for it.

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Thylacine

Last call

It had been dry and cloudless for many weeks in Maryland when the earth finally spun into equinox. A tiny spring peeper was discovered clinging to a wall, and a large toad took up residence in the hollow climbing log on the playgfroground.  Both had swollen bellies, as if they were maintaining their body moisture from within. The kids found an imperial moth caterpillar moving sluggishly under pine trees and brought it to be photographed.  In the garden, a black swallowtail caterpillar munched its way along carrot leaves, along with the tiniest isabella moth caterpillar I’ve ever seen.

When I teach a lesson on winter adaptations, it’s hard to impart to kids the simultaneous urgency and inevitable slowing-down that these creatures must experience at this time of year.  This week, early fall storm systems have brought drenching rains and cooler temperatures, reinforcing the cues of diminishing day length and angle of sunlight.  Torpor, the entry into  suspended animation of body systems that cold-blooded animals rely on to survive freezing temperatures, will begin to occur – ready or not.  Many of the young mammals who are my students continue to race around outdoors in apparent disregard of metabolic challenges. Some decline to wear extra layers for insulation, claiming – and who could refute it but the animal herself? – that they don’t feel cold. They will happily go about their normal, carefree play activities while others (including their teachers) huddle nearby in heavy coats or abandon these flimsy insulation efforts to seek heat indoors. It is a season of differentiation, a time when human perception of affordances includes a new array of sensory information and leads to a self-sorting at different levels of resilience and opportunity.

mouseOn one of those last warm days of September, a cry went up from the pine woods: “A mouse!” By the time I arrived, a protective barrier of rocks had been placed around the pile of stones and leaves where a young deer (or white-footed?) mouse sat hunched and quivering.  “It’s cold! We should take it inside!” one child offered. Another replied that she thought it was just scared, and a third commented that it couldn’t be cold with a fur coat.  We watched it for a minute, talking about how well it could manage on its own out here.  They concluded that if it had to remain outside, they could at least provide it with some better shelter, and set to work constructing a mouse house from sticks nearby.  20 minutes later, when I dropped by to see their progress, I was informed that the mouse had disappeared, but that they intended to complete the house anyway, and to keep it stocked with seeds from the sunflowers in the garden –“So it can choose what it wants to do.”

Camo

camolooper-2Today was all about the little things, most of which seem determined not to be seen.  Squatting and peering under leaves, following a tiny moth as it fluttered through the grass, searching for the host of a web spun between pine needles, I paused to consider the brown, out-of-place petals protruding from a flower corolla.  Then I realized that they were moving of their own accord. This recalled another such instance on a hike, when a similar assortment of petals made its way across a daisy, and turned out to be the caterpillar of an emerald moth, or a camouflage looper. This current ragamuffin, which had attached bits of petal to itself until completely covered, was so minute that I couldn’t tell how best to photograph it, or where a head or legs might even be.  Its movements were erratic; it appeared to lift its head every so often and then lower it to resume feeding, blending in with the other petals.

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Rounding the corner into the garden, I looked hard at the zinnias and cosmos, expecting a spider at least, but found nothing.  The joe-pye weed had nearly all gone to seed, but the last bit of pink betrayed an ominous shape: a jagged ambush bug. It straddled a blossom like an apocalyptic insect horseman, its round eyes bulging and its fearsome hooked forelegs ready to pounce. Only a few millimeters long, it tackles prey many times its size.

I wonder if an ambush bug would be fooled by a camouflage looper, or if the looper would notice the ambush bug.

Rainbow

The old dog and I walked out to the meadow by the house, she to slowly wander about considering pooping, and I to scan the grasses for butterflies.The pile of deer dung lying under the white oak looked fresh.  There are many of these right now where the deer have stood chewing their acorn/yard shrub cud. I decided it was worth flicking this one into the woods with my trowel so that the dog wouldn’t eat or roll in one of her favorite fragrances. The pile was softer than I expected, and split apart when I nudged it, revealing the startling glimmer of a chunky, iridescent beetle lodged in the center.  My first thought was, “Now why was a deer eating June bugs?” Then I saw a large horn protruding from the pronotum, bright green elytra, and ruby red shining over its thorax.  Whatever it was, I needed my camera.  When I returned and photographed its awkward, disoriented journey down the length of the trowel, I was still astounded.  This creature had never crossed my path before.  I could guess at some of its taxonomy, but only up to dung beetle.  And who had ever heard of a beetle that spends its life working dung into balls for the benefit of its young having such incredibly vivid colors?  Why would it?

rainbow1This morning I shared the wonder of this discovery with my M Group students, first showing them a photo, and then asking them to try classifying it.  They all agreed on beetle, but beyond that was a mystery.  I clarified where and how I found it, and then showed them how to search with the terms that they knew or observed – beetle found in deer dung, shiny, rainbow colors, horn. And there it was, the rainbow scarab, Phanaeus vindex, pharaoh of the dung heap.

And why the bright colors? “Because if you lived in poop, you’d want to look all sparkly so no one would think you were poop.”