Bird (class Aves), any of the 9,600 living species unique in having feather,
the major characteristic that distinguishes them from all other
animals. A more elaborate definition would note that they are
warm-blooded vertebrates more related to reptiles than to mammals and
that they have a four-chambered heart (as do mammals), forelimbs
modified into wings (a trait shared with bats), a hard-shelled egg, and
keen vision, the major sense they rely on for information about the
environment. Their sense of smell is not highly developed, and auditory
range is limited. Most birds are diurnal in habit. More than 1,000
extinct species have been identified from fossil remains.
Bird
Bird
Bird
Bird
Bird
Bird
Bird
Bird
Bird
No comments:
Post a Comment