▁brown , ▁o live ▁brown , ▁grey , ▁yellow ish ▁and ▁r uf ous . ▁However , ▁it ▁can ▁light en ▁and ▁dark en ▁its ▁skin ▁to ▁match ▁its ▁surr ound ings . ▁Some ▁individuals ▁have ▁more ▁unusual ▁colour ation — both ▁black ▁and ▁red ▁individuals ▁have ▁been ▁found ▁in ▁Scotland , ▁and ▁alb ino ▁fro gs ▁have ▁been ▁found ▁with ▁yellow ▁skin ▁and ▁red ▁eyes . ▁During ▁the ▁m ating ▁season ▁the ▁male ▁common ▁f rog ▁tends ▁to ▁turn ▁grey ish - blue ▁( see ▁video ▁below ). ▁The ▁average ▁mass ▁is ▁; ▁the ▁female ▁is ▁usually ▁slightly ▁larger ▁than ▁the ▁male . ▁ ▁The ▁fl anks , ▁lim bs ▁and ▁back s ▁are ▁covered ▁with ▁irregular ▁dark ▁bl ot ches ▁and ▁they ▁usually ▁sport ▁a ▁che v ron - sh aped ▁spot ▁on ▁the ▁back ▁of ▁their ▁neck ▁and ▁a ▁dark ▁spot ▁behind ▁the ▁eye . ▁Un like ▁other ▁am ph ib ians , ▁common ▁fro gs ▁generally ▁lack ▁a ▁mid - d ors al ▁band ▁but , ▁when ▁they ▁have ▁one , ▁it ▁is ▁compar atively ▁faint . ▁In ▁many ▁countries ▁mo or ▁fro gs ▁have ▁a ▁light ▁d ors al ▁band ▁which ▁easily ▁distingu ishes ▁them ▁from ▁common ▁fro gs . ▁The ▁under bel ly ▁is ▁white ▁or ▁yellow ▁( occ asion ally ▁more ▁orange ▁in ▁females ) ▁and ▁can ▁be ▁spe ck led ▁with ▁brown ▁or ▁orange . ▁The ▁eyes ▁are ▁brown ▁with ▁transparent ▁horizontal ▁pup ils , ▁and ▁they ▁have ▁transparent ▁inner ▁e y el ids ▁to