Mammalogy is the scientific study of mammals, a class of warm-blooded vertebrates that typically have hair or fur, give birth to live young (rather than laying eggs), and nurse their offspring with milk produced by mammary glands. Mammalogists study the diversity, ecology, behavior, evolution, and conservation of mammals, which include a wide range of species from tiny shrews to massive whales. Research in mammalogy is important for understanding the role of mammals in ecosystems, their adaptations to different environments, and the threats they face from habitat loss, climate change, and other human activities.