animali

Animali, or animals, refers to the diverse group of multicellular, eukaryotic organisms belonging to the kingdom Animalia. They are characterized by their heterotrophic nutrition, lack of rigid cell walls, most possess bodies organized into tissues and organs, and most are capable of voluntary movement at least during early development.

Animal diversity is vast, ranging from simple sponges to complex mammals. They are divided into invertebrates, which lack a backbone, and vertebrates, which possess one. The majority of animal species are invertebrates, including arthropods, mollusks, annelids, cnidarians, and echinoderms. Vertebrates include fish, amphibians, reptiles, birds, and mammals.

Most animals reproduce sexually, with a life cycle that typically includes developmental stages such as embryonic formation and, in many lineages, metamorphosis. They digest food through intracellular or extracellular digestion and generally obtain energy by consuming other organisms or organic matter.

Ecologically, animals occupy nearly every habitat, play key roles as predators, herbivores, scavengers, and pollinators, and form complex ecological networks. They communicate using sound, vision, chemical signals, and tactile cues, and many display social behaviors and learned behaviors.

Humans interact with animals through domestication, agriculture, research, and conservation. Some species are kept as companions; many wild species face threats from habitat loss, climate change, overexploitation, and pollution. Conservation efforts aim to protect biodiversity and maintain ecosystem services.