 The gestation period ranges from 41 to 47 days . More litters are born in warm climates : the number of litters born each year ranges from two per year in Idaho to seven in Arizona . Litter sizes are largest in the northern portions of black @-@ tailed jackrabbit 's range and decrease toward the south . Average litter size has been reported at 4 @.@ 9 in Idaho , 3 @.@ 8 in Utah , and 2 @.@ 2 in Arizona . 
 The gestation period <a href='uninflect' title='1'><mark>ranges</mark></a> from 41 to 47 days . More litters are born in warm climates : the number of litters born each year <a href='uninflect' title='2'><mark>ranges</mark></a> from two per year in Idaho to seven in Arizona . Litter sizes <a href='drop_aux' title='3'><mark>are</mark></a>largest in the northern portions of black @-@ tailed jackrabbit <a href='null_genetive' title='4'><mark>'s</mark></a>range and decrease toward the south . Average litter size <a href='been_done' title='5'><mark>has</mark></a> been reported at 4 @.@ 9 in Idaho , 3 @.@ 8 in Utah , and 2 @.@ 2 in Arizona . 
Da gestation period range from 41 to 47 days . More litters are born in warm climates : the number of litters born each year range from two per year in Idaho to seven in Arizona . Litter sizes largest in the northern portions of black @-@ tailed jackrabbit  range and decrease toward the south . Average litter size done been reported at 4 @.@ 9 in Idaho , 3 @.@ 8 in Utah , and 2 @.@ 2 in Arizona .