Puncture resistant heat shrinkable film containing narrow molecular weight ethylene alpha olefin

A heat shrinkable, puncture resistant, biaxially stretched thermoplastic film suitable for use in fabricating bags for packaging food articles comprising a polyethylene which is a linear copolymer of ethylene and higher alpha olefin containing from 4 to 8 carbon atoms, having a density between about 0.88 and about 0.905 g/cm.sup.3, a melt index not exceeding about 1.0 g/10 min, a molecular weight/size distribution ratio Mw/Mn below about 3, a melting point below about 100.degree. C., a Young's Modulus of below about 750 kg/cm.sup.2, and wherein said film shrinks at least about 50 percent at a temperature of about 90.degree. C. in at least one of the machine and transverse directions.