▁up ▁to ▁a ▁couple ▁of ▁weeks , ▁during ▁which ▁the ▁body ▁temperature ▁dro ps ▁by ▁ 1 0 ▁degrees ▁Cel si us ▁or ▁more , ▁separated ▁by ▁brief ▁periods ▁of ▁ar ous al . ▁ ▁Re production ▁Asia ▁Minor ▁ground ▁squ ir rel s ▁mate ▁under ground ▁shortly ▁after ▁emer ging ▁from ▁hi bern ation ▁in ▁March ▁or ▁April . ▁During ▁the ▁m ating ▁season , ▁males ▁travel ▁between ▁several ▁females , ▁and ▁may ▁fight ▁with ▁each ▁other ▁for ▁access ▁to ▁m ates . ▁The ▁females ▁produce ▁a ▁single ▁l itter ▁of ▁three ▁to ▁nine ▁( although ▁most ▁commonly ▁four ▁or ▁five ) ▁young ▁each ▁year , ▁and ▁gest ation ▁last s ▁around ▁ 2 5 ▁days . ▁The ▁young ▁are ▁born ▁blind ▁and ▁hair less , ▁we igh ing ▁. ▁The ▁fur ▁begins ▁to ▁appear ▁at ▁ 1 5 ▁days , ▁and ▁the ▁eyes ▁open ▁at ▁ 2 2 – 2 5 ▁days . ▁By ▁four ▁weeks ▁of ▁age , ▁they ▁begin ▁to ▁leave ▁the ▁bur row , ▁and ▁they ▁are ▁fully ▁we an ed ▁by ▁seven ▁weeks . ▁ ▁E volution ▁F oss ils ▁of ▁Asia ▁Minor ▁ground ▁squ ir rel s ▁are ▁known ▁from ▁the ▁early ▁Ple ist oc ene , ▁and ▁include ▁some ▁spec im ens ▁from ▁as ▁far ▁west ▁as ▁Ch ios , ▁suggesting ▁that ▁the ▁species ▁formerly ▁had ▁a ▁wider ▁distribution ▁than ▁it ▁does ▁today . ▁ ▁Bio chem ical ▁studies ▁indicate ▁that ▁the ▁species ▁diver ged ▁from ▁the ▁common ▁ancest or ▁of ▁the ▁European ▁sous lik