Birds

Birds

Birds are warm-blooded, vertebrate animals that walk, jump, or stand only on the hind limbs, while the forelimbs have evolved into wings that, like many other unique anatomical features, allow them to in most cases, fly, although not all fly. Their bodies are covered in feathers and, birds sensu stricto, a horny beak without teeth. To reproduce, they lay eggs that hatch until hatching.

Its taxonomic group is called class Aves (the word is Latin and is in the plural, in the singular it would be avis) for classical systematics, but in current phylogenetic systematics this clade has no rank, and it is included in turn within the clades: Theropoda, Dinosauria, Archosauria, Sauropsida, Tetrapoda, etc., although there are more intermediate nesting with names.

Birds originated from bipedal carnivorous dinosaurs from the Jurassic, 150-200 million years ago, and are, in fact, the only dinosaurs to survive the mass extinction produced at the end of the Mesozoic. Its evolution gave rise, after strong radiation, to the more than 10,000 current species (more than 153 extinct in historical times)

Birds are the most diverse tetrapods; however, they have great morphological homogeneity compared to mammals. The kinship relationships of the bird families cannot always be defined by morphology, but with DNA analysis they began to become clear.

Birds inhabit all terrestrial biomes and also in all oceans. The size can be from 6,4 cm in the zunzuncito hummingbird to 2,74 meters in the ostrich. Behaviors are diverse and remarkable, such as in nesting, baby feeding, migrations, mating, and the tendency for group association. Communication between birds is variable and can involve visual cues, calls, and singing. Some emit great diversity of sounds, and stand out for their intelligence and for the ability to culturally transmit knowledge to new generations.