Monotremék

Monotremes are a group of mammals that lay eggs instead of giving birth to live young like most other mammals. The group includes three living species: the platypus, the echidna, and the extinct ornithorhynchid and chlamydoselachians.

The term monotreme was coined by the Australian zoologist Richard Owen in 1861. It is derived from the Greek words "monos," meaning single, and "trēma," meaning hole or burrow, in reference to the fact that one of the two main openings in the skull of monotremes leads to the nasal passages, the other leading to the ear.

All monotremes have a similar body structure, with a flat, beaver-like tail and webbed feet. They are found in eastern Australia, New Guinea, and nearby islands. The platypus is the most well-known monotreme, and is considered to be one of the most unusual mammals in the world.

Monotremes are carnivorous, with the platypus and echidna feeding on insects, worms, and small invertebrates, while the extinct Monotrematae were known to have fed on a variety of fish and other aquatic animals. The reproductive system of monotremes is also unique, with males producing venom in their venom glands, which are located in their hind legs.

Despite their unusual characteristics, monotremes have been on Earth for a long time, with fossil records indicating that they date back at least 160 million years. However, very little is known about their early history and evolution. Research on monotremes continues, but much more remains to be learned about these fascinating creatures.