Q: What type of mammals did we have when dinos were around? -Caden
A: That is a wonderful question, Caden. The Mesozoic was an amazing era of life. Dinosaurs became the dominant creatures, the first birds took flight and giant reptiles roamed the seas. A lot of people don’t realize that mammals even existed during this time which is incredible because 2/3 of mammalian history occurred in the Mesozoic!
Mammals of the Mesozoic weren’t the mammals that we see today, virtually all of them were very small rodents that fed on insects. One of the most common that we’ve found is a little guy called Morganucodon that was about 10cm long. He had goofy little teeth and scuttled around awkwardly on hind legs that stuck out from it’s body.

Morganucodon
The biggest mammals that were around in the Mesozoic were about as big as a medium-sized dog. Repenomamus was about 50cm (20in) long and there is good evidence that it actually fed on dinosaurs. A couple fossils have been found that contained dinosaur bones in it’s stomach.

Repenomamus
Although these guys were able to eek out a living, dinosaurs were still kings of the Mesozoic. At least we know where they got a start.
-Rex