When the British first founded Hobart in southern Tasmania, they did not realize that they were on an island, that they were not on the continent of Australia. Then they heard that the French had discovered this fact and were nosing around in the passage on the northern end of the island. They quickly built Launceston on the River Tamar, about thirty miles from the sea. The convicts transported there built beautiful buildings, bridges and roads and the town flourished.
Launceston is located in a glacial valley and the Tamar River eroded the weaker rock and created a beautiful gorge, which today contains the community swimming pool and a walkway along one side of the river. On another gorgeous day we walked along the river admiring the wallabies and unique vegetation. Later in the day we returned to the gorge on a small boat and admired the canyon walls from below. Even this far inland, the river is influenced by tidal changes. The fresh water flows on the surface with the denser salt water below.
When you come to Australia, you expect to see some of the unique marsupials found nowhere else in the world. Last time we were here, we never saw the duck-billed platypus. Today this serious omission was remedied. While the platypus does well in this part of the world, it is not easily kept in zoos. When people first saw this creature cavorting in the rivers, they thought it was a joke. Its main body is covered with lush fur, but the fur on its flat beaver-ish tail is harsh and bristly. The soft fur traps air and acts like a life jacket, but when the platypus wants to dive, it tightens its muscles and the water is released in a large bubble. Its duck-bill is covered with pores which sense the electricity given off by the tiny bugs and grubs in the water that are its prey. The platypus feeds by neither sight nor smell, closing its eyes, ears, and nose each time it dives. When it digs in the bottom of streams with its bill, its electroreceptors detect tiny electric currents generated by muscular contractions of its prey, so enabling it to distinguish between animate and inanimate objects, which continuously stimulate its mechanoreceptors. Experiments have shown the platypus will even react to an "artificial shrimp" if a small electric current is passed through it. Its feet are rubbery and duck-like. The females lay eggs and once they hatch, their young are fed with milk that oozes out of their mammary glands; they have no teats. The females would be easy to keep as pets, but early settlers quickly learned not to mess with the males, which are very territorial. Ideally, the males has about six miles of stream as his territory and keeps a harem of females equally spaced along its banks. He patrols the stream constantly to ensure that no other males have intruded on his river or his ladies. If one does, he has an ankle spur which delivers a venom so powerful that it will instantly kill smaller animals such as dogs. The platypus has been known to kill a crocodile. While the venom is not lethal to humans, but the pain it causes is so excruciating that the victim may be incapacitated for months or even years. Each platypus has a unique version of this venom, so no anti-venom exists. Recently a man who accidentally encountered a platypus while he was working in the river was released after spending sixteen months in the hospital. If the male discovers that his harem has been intruded upon, he kills the females as well. Gotta protect that gene pool!
At the platypus house we also met the echidna, a much fiercer looking, but much gentler creature. They look like porcupines with fur and placidly waddle around looking for bugs they can lasso with their long, prehensile tongues. Like the platypus, they are equipped with electrosensors. They are powerful diggers and when threatened they dig a hole and role up in it, displaying their quills. Although both creatures look like mammals, they lay eggs. Although many tourists came to Platypus House while we were there, only our tour was taken behind the scenes by a knowledgeable young man who answered our incessant questions until we had no more.