The concept of Degrees of Freedom is a mathematical idea that suggests there is one degree of freedom for every independant mode of motion.
For example the ERS210?'s Degrees of Freedom can be calculated as follows.
|Mouth||1 Degree of Freedom|
|Head||3 Degrees of Freedom|
|Legs||3 Degrees of Freedom (x4 Legs)|
|Ears||1 Degree of Freedom (x2 Ears)|
|Tail||2 Degrees of Freedom|
| || |
|Total||20 Degrees of Freedom|