XW: There are numerous anatomical distinctions between cats (felids) and dogs. Q: How do dogs differ from cats? What are their similarities?

Evolutionarily, canids are flexible (adaptable) predators that were often quick to take advantage of opportunities that resulted from the occasional extinction of other carnivorans. Having the ability to form a complex social group and the capacity to pursue prey in a highly organized manner are characteristics of the dog family (only the hyena family shares these traits with the canids among the carnivorans). XW: Social hunting is one of the trade-marks of modern wolves. Canids thrive in such an environment and the great number of fossils of members of this family testifies to their success. The global climate became cooler and drier during the late Cenozoic, conditions that favor grassland over trees. In addition, there are rich fossil records for canids because they evolved adaptations to a more cursorial locomotion (capable of running fast and for long distances), which is ideal for living in open grassland. This long history gave canids an early head start in diversifying before other carnivoran groups had an opportunity to compete. XW: Canids were among the first carnivorans to evolve, dating back to more than 40 million years ago. Q: Why are the fossil records for canids so rich and abundant? Such fantastic records, assembled over more than 100 years of careful collecting by vertebrate paleontologists, permit us to piece together a detailed evolutionary history of the family and enable us to ask many questions that cannot be easily answered by studying other groups of carnivorans.

The richness and diversity of the fossil canids are unparalleled among modern families of Carnivora (mammalian predators). Xiaoming Wang: The fossil records of the canids (dogs) present a unique opportunity to study this important family of predators. Wang is a curator of vertebrate paleontology at the Natural History Museum of Los Angeles County and has been studying the evolutionary history of the family Canidae for the past 20 years. The following is an interview with Xiaoming Wang, author of Dogs: Their Fossil Relatives and Evolutionary History.

Dogs by Xiaoming Wang