mælkedyr

Mælkedyr is the Danish term for mammals. Mammals are a class of vertebrate animals characterized by the presence of mammary glands which in females produce milk for nourishing their young. Other defining characteristics include a neocortex region in the brain, hair or fur, and three middle ear bones. Mammals are also warm-blooded, meaning they can regulate their own body temperature internally.

The mammalian class is incredibly diverse, encompassing a vast array of species found across all continents and in nearly every habitat on Earth. This includes familiar animals like dogs, cats, horses, elephants, and humans, as well as less common ones such as bats, whales, and echidnas. They range in size from the tiny bumblebee bat to the enormous blue whale.

Reproduction in mammals is typically sexual, and most give birth to live young. However, a small group called monotremes, like the platypus and echidna, lay eggs. Parental care is a significant aspect of mammalian life, with young often relying on their mothers for an extended period for survival and learning. This nurturing behavior is facilitated by the milk produced by the mammary glands, which provides essential nutrients and antibodies. The diversity of mammalian adaptations reflects their long evolutionary history and their ability to thrive in various ecological niches.