Confuciusornis, the "Confucius
Bird," is a well-documented
genus of animals from the Yixian and
Jiufotang Formations in China. With
a length of fifty centimeters and a
wingspan of seventy centimeters, the
Confuciusornis was not very
different from modern birds. It was 
one of the earliest birds known to 
have a toothless beak, despite not
being closely related to modern 
birds. The beak therefore developed 
through convergent evolution, which 
is the evolution of similar features 
in unrelated animals. Fossils of its 
wings include many melanosomes 
(cells that contain pigment), allow-
ing us to learn that it was colored
grey, red/brown, and black. The 
wings were probably white, with the 
long tail feathers being dark along 
their entire length. 

Confuciusornis was a piscivore, 
catching and feeding upon small 
Cretaceous fish with its beak. This
diet is demonstrated in a fossil 
specimen preserved with its last 
meal in its belly, similar to the
famous Compsognathus fossils. As a
whole, Confuciusornis fossils are 
intriguing because some have the 
long tail feathers but others do 
not, and some are much larger than
others. The best explanation for 
this variability is sexual dimorph-
ism: the leading hypothesis states 
that the larger ones are the 
females, and both sexes lost the 
feathers during molting season.
