Monotremes are a unique group of egg-laying mammals, primarily found in Australia and New Guinea. The most well-known monotremes are the platypus and the echidna. Unlike most mammals, they reproduce by laying eggs rather than giving birth to live young, which sets them apart in the animal kingdom. These fascinating creatures possess a mix of mammalian and reptilian traits. For instance, they have fur and produce milk for their young, but they also have a cloaca, a single opening for excretion and reproduction, similar to reptiles. This combination of features makes monotremes a subject of great interest in evolutionary biology.