 The species is intermediate in size for the Akodon boliviensis species group ; it is smaller than A. polopi and A. sylvanus , but larger than A. boliviensis and A. caenosus . The more distantly related A. budini and A. simulator , which occur in the same area , are larger . Akodon spegazzinii is variable in coloration , ranging from light to dark and from reddish to yellowish brown . In general , animals in wetter , lower @-@ lying areas are darker , and those in open , dry environments are paler . However , there is also variation within populations , and sometimes young mice are darker and lactating females are more reddish . The formerly recognized species Akodon tucumanensis corresponds to the dark , low @-@ altitude populations , while A. leucolimnaeus and A. alterus represent more reddish , high @-@ altitude animals . 
