Although generally larger in size, the yellow-necked mouse (Apodemus flavicollis) is very similar in appearance to the wood mouse (Apodemus sylvaticus) and the two are often difficult to distinguish. Both species have brown fur with paler, white bellies, although the yellow-necked mouse may often be somewhat lighter in colour. The main difference between these mice is that, as the name suggests, the yellow-necked mouse has a collar of yellowish fur, which forms a bib on the chest. This collar is often fairly difficult to see, however.