nisäviä

Nisäviä is a Finnish term that translates to "mammals" in English. It refers to the class Mammalia, a diverse group of warm-blooded vertebrate animals characterized by the presence of mammary glands in females, which produce milk to nourish their young. Other defining features of mammals include having hair or fur on their bodies, a neocortex region in the brain, and three middle ear bones.

Mammals are found in virtually every habitat on Earth, from the deepest oceans to the highest mountains, and inhabit a wide range of ecological niches. They exhibit a remarkable diversity in size, form, and behavior, encompassing creatures as varied as tiny shrews and enormous whales, flying bats and burrowing moles, and the vast array of terrestrial species including primates, rodents, carnivores, and ungulates.

Reproduction in mammals is typically sexual, and most species give birth to live young, although a small group known as monotremes, such as the platypus and echidnas, lay eggs. Parental care is generally well-developed in mammals, with mothers often investing significant time and energy in raising their offspring. This extended period of care allows for learning and development, contributing to the complex social behaviors observed in many mammalian species. The study of mammals is known as mammalogy.