Dr. Meng Jin studies the morphology, systematics, and evolution of mammals, particularly early mammals. He examines the cranium, ear region, and enamel microstructure of teeth as sources of data to address evolutionary issues concerning mammals. Most of Dr. Meng's fieldwork takes place in Asia—primarily in Inner Mongolia, Xinjiang Province in northeast China, and southern China. Most recently, Dr. Meng and his colleagues published research on a fossil of a 130-million-year-old opossum-sized mammal found with the remains of a psittacosaur in its stomach area—the first direct evidence that some primitive mammals were carnivores and fed on small vertebrates, including young dinosaurs.