Bird
Birds (class Aves) are feathered, winged, bipedal, endothermic (warm-blooded), egg-laying, vertebrate animals. With around 10,000 living species, they are the most speciose class of tetrapod vertebrates. All present species belong to the subclass Neornithes, and inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from the 5 cm (2 in) Bee Hummingbird to the 2.75 m (9 ft) Ostrich. The fossil record indicates that birds emerged within theropod dinosaurs during the Jurassic period, around 160 million years (Ma) ago. Paleontologists regard birds as the only clade of dinosaurs to have survived the Cretaceous–Paleogene extinction event 65.5 Ma (million years) ago.
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Famous quotes containing the word bird:
“The caged bird sings
with a fearful trill
of things unknown
but longed for still
and his tune is heard
on the distant hill
for the caged bird
sings of freedom.”
—Maya Angelou (b. 1928)
“The first lady is, and always has been, an unpaid public servant elected by one person, her husband.”
—Lady Bird Johnson (b. 1912)
“I’ll be a new bird with the head of an ass,
Two pigs’ feet, two men’s feet, and two of a hen”
—Thomas Lovell Beddoes (1803–1849)