A Look at the Science How Birds Developed from Dinosaurs

Microraptor swallowing Indrasaurus wangi. Image credit: Doyle Trankina.

As I continued to read the NY Times Best-seller "The Rise and Fall of the Dinosaurs" by
Steve Brusatte, I'm fascinated by how life evolved on this planet. In today's blog, I'll examine the science that uncovered how birds developed from one branch of dinosaurs, as highlighted in Steve's book. In today's blog you'll learn about feathers, feet, air sacs, wishbones and an primitive bird discovered in 2019:>>>

modern day bird feet types

FEATHERS- Steve noted in his book that some dinosaurs during the Jurassic and Cretaceous periods had filament-like projections from their skin. They were apparently used to keep the dinosaurs warm and served other purposes, like camouflaging them from prey. Even tyrannosaurs had them. Those filaments eventually became quills and then ultimately, feathers.

BIRD FEET - When you think about how birds have skinny legs and 3 skinny main toes, dinosaurs had similar feet. Those characteristics first appeared about 230 million years ago in dinosaurs!

Foot of a Struthiomimus. A dinosaur that lived in the late Cretaceous period, between about 76 and 74 million years ago. Struthiomimus was about 14 feet  long, and about 4½ feet tall at the hips. It is believed to have weighed around 330 pounds  

DID DINOSAURS HAVE WISHBONES?  As some of those dinosaurs evolved, their right and left collarbones fused together, making a wishbone- such as what we see today in chicken and turkey. Wishbones stabilized these creatures to hold on to prey.

SPECIAL AIR SACS - Some dinosaurs, like birds, have special air sacs that allow them to intake oxygen even when they are exhaling. It was those air sacs that allowed dinosaurs to grow to enormous sizes, too - by continually inputting oxygen into their bodies. Steve refers to it as a "flow-through lung" and it developed over 100 million years before birds took wing.

Microraptor preserving the lizard  in its stomach. credit: O’Connor et al.

AN ANCIENT BIRD: THE MICRORAPTOR:  The microraptor -is one of the first feathered dinosaurs. This "bird" was discovered in 2019. Here's the story from Si-News Com: 

Paleontologists in China have uncovered a nearly complete, fully articulated skeleton of Microraptor zhaoianus, a pigeon-sized, four-winged dinosaur that lived about 120 million years ago, and found an additional surprise preserved in its stomach: a previously unknown species of prehistoric lizard. The unique Microraptor specimen was collected in deposits of the Jiufotang Formation near Jianchang in Liaoning Province, northeastern China, and was acquired by paleontologists in 2005.  Both the dinosaur and the lizard were part of the so-called Jehol Biota, an early Cretaceous terrestrial and freshwater ecosystem preserved in a multi-layered rock formation cropping out in the Chinese provinces of Liaoning, Hebei and Inner Mongolia and famous for exceptionally preserved remnants of early birds, feathered dinosaurs, primitive mammals and ancient plants.