Platypus

Platypuses (Ornithorhynchus annatinus) sometimes referred to as the **duck-billed platypus** are the most primitive animals and wierdest in the mammal kingdom .The most typical animalsthat lay eggs in mammal Class . Mostly live in Australia and Tasmania island.

Until the early 20th century, it was hunted for its fur, but it is now protected throughout its range. Although captive breeding programs have had only limited success and the platypus is vulnerable to the effects of pollution, it is not under any immediate threat.

## Weird appearance

   Platypuses are mammals but they look just like birds : whole body is covered with black , think feathers , their body is really similar to Otters' , long large tail like Beavers' ,between their toes are oars , flat muzzle .Their feet and mouth like duck's.

## Great swimmer

The platypus is an excellent swimmer and spends much of its time in the water foraging for food. When swimming, it can be distinguished from other Australian mammals by the absence of visible ears. Uniquely among mammals, it propels itself when swimming by an alternate rowing motion of the front feet; although all four feet of the platypus are webbed, the hind feet (which are held against the body) do not assist in propulsion, but are used for steering in combination with the tail.The species is endothermic, maintaining its body temperature at about 32 °C (90 °F), lower than most mammals, even while foraging for hours in water below 5 °C (41 °F)

Dives normally last around 30 seconds, but can last longer, although few exceed the estimated aerobic limit of 40 seconds. Recovery at the surface between dives commonly takes from 10 to 20 seconds.

When not in the water, the platypus retires to a short, straight resting burrow of oval cross-section, nearly always in the riverbank not far above water level, and often hidden under a protective tangle of roots

## Diet

The platypus is a carnivore: it feeds on annelid worms, insect larvae, freshwater shrimp, and freshwater yabby that it digs out of the riverbed with its snout or catches while swimming. It uses cheek-pouches to carry prey to the surface, where it is eaten.[51] The platypus needs to eat about 20% of its own weight each day, which requires it to spend an average of 12 hours daily looking for food

## Children caring

the female pltypus lay soft shell eggs,then hatching like birds after about 10 days, the babies crake the eggs

to come out , by then they only 3 centimeters long . can not see and have no tail.the mother procumbents for the babies to drink milk.6 months later the babies can go to the river to find foods by themselves.

1. To the breeding season the platypus dig a tunnul to lay eggs
2. Each terms platypus lay 2 - 8 eggs
3. platypus is one of the rare mammal which have vemon
4. Cause the female do not have nipples ,milk drench over the bellyskin to the fur , the baboes will lick the milk on it

## Liquid weapon

While both male and female platypuses are born with ankle spurs, only the male's spurs deliver venom, composed largely of defensin-like proteins (DLPs), three of which are unique to the platypus. The DLPs are produced by the immune system of the platypus. The function of defensins is to cause lysis in pathogenic bacteria and viruses, but in platypuses they also are formed into venom for defense. Although powerful enough to kill smaller animals such as dogs, the venom is not lethal to humans, but the pain is so excruciating that the victim may be incapacitated. Oedema rapidly develops around the wound and gradually spreads throughout the affected limb. Information obtained from case histories and anecdotal evidence indicates the pain develops into a long-lasting hyperalgesia (a heightened sensitivity to pain) that persists for days or even months. Venom is produced in the crural glands of the male, which are kidney-shaped alveolar glands connected by a thin-walled duct to a calcaneus spur on each hind limb. The female platypus, in common with echidnas, has rudimentary spur buds that do not develop (dropping off before the end of their first year) and lack functional crural glands.

The venom appears to have a different function from those produced by nonmammalian species; its effects are not life-threatening to humans, but nevertheless powerful enough to seriously impair the victim. Since only males produce venom and production rises during the breeding season, it may be used as an offensive weapon to assert dominance during this period.