Mammals are warm-blooded tetrapod vertebrates that evolved from reptilian ancestors during the late Triassic period around 225 million years ago. This chapter focuses on some of the most distinctive mammalian characteristics and on integrated robotic systems that seek to capture these capabilities in biomimetic artifacts. Topics covered include the mammalian brain, novel sensory systems, agile locomotion, dextrous grasp, and social cognition. Attempts to build integrated robotic systems that broadly match the behaviour and appearance of specific mammalian species have focused most strongly on humans, on quadrupeds such as cats and dogs, and on rodents. The goal of creating robots that resemble mammals will be encouraged by interest in mammal-like robots that can emulate some of the capacities for social companionship provided by domesticated mammals such as rabbits, dogs, and cats.