Ornithorhynchus anatinus Shaw, 1799
The three objects are a short-beaked echidna, a long-beaked echidna, and a duckbill or platypus. They belong to a special groupe of mammals.
What is a mammal?
Furthermore, the female lacks teats. Instead, milk is released through pores in the skin. There are grooves on her abdomen in which the milk pools. The young lap it up from there.
We will limit ourselves to the platypus. It is a strange mammal: It has the bill of a duck, the tail of a beaver, the feet of an otter, it is furry and it has a cloaca, the common opening for the intestinal, reproductive, and urinary tracts. The first skin of a duck-billed platypus arrived in England in 1799. At the British Museum people thought it must be a hoax. It took a long time before it was recognized as a true animal. Why did the scientists not believe it was a real animal? In those days, rich people collected anything rare and brought together their collected items in so-called curiosity cabinets: ancient coins, all kinds of artefacts, animals, rocks, fossils. At some point no more special animals could be found. Then the animal traders invented new kinds of animal by combining parts of different species: hence the suspicion amongst the biologists.
Is it a male or a female? It is a male, because it has spurs on its hind legs. The platypus is one of the few venomous mammals. The male has a hollow horny spur on the ankles of both hind legs, which is connected to a venom gland in the thigh. This spur is about an inch long in an adult male. He mainly uses them in fights with other males during the mating season. A young female also has a spur, but it is reduced. The spur reaches a maximum length of half a centimeter and falls off when it is 8 to 10 months old. The venom contains over eighty different toxic compounds, including defensin-like proteins, three of which are unique to the platypus. It can be deadly to animals up to the size of a dog.