Adder is a snake who makes the journey from Farthing Wood to White Deer Park in both the books and the TV series. Adder is male in the books, but is female in the TV series. Adder shows very little emotion to the other animals and is seemingly uninterested in upholding the oath.
However, Adder does help the other creatures on many occasions; such as saving Vixen from the hunt and distracting Jack while the other animals escape from the farm. Having originally isolated himself/herself in the park, Adder grows fonder of the other animal`s company over time and acts in a much more friendly manner late in the series.
