Many of the more successful or well-known robots seen today are based on animals. In the end it’s likely more research dollars will go to animal bots than humanoids. Their specialized nature makes them a great blueprint for engineers building robots to be used in dangerous environments.
Like many of their animal models, these robotic animals were almost all created to solve a problem or serve a purpose (even if it is just to keep people company). Animals robots aren’t the only ones built to serve, there are plenty of humanoid models as well.