 During peak sexual activity , males engage in combat . This starts with one male rubbing its chin along the back of the other . The second male will then raise its head as high as possible . As they both do the same , the necks intertwine . When the heads are level , they turn towards each other and push . Their bodies intertwine as they switch positions . They become oblivious to everything else , continuing even after they fall off a surface or into water . Sometimes they intertwine and squeeze so tightly that their scales stand out from the pressure . They have also been observed to strike at each other with mouths closed . Occasionally , the combatants will tire and break off the fight by " mutual consent " , resting for a while before resuming once more . The event is settled when one of the two succeeds in pushing the other 's head to the ground and raising its own by 20 – 30 cm . In captivity , combat may occur four or five times a week until courtship and copulation ends . 
 During peak sexual activity , males engage in combat . This <a href='uninflect' title='1'><mark>starts</mark></a> with one male rubbing its chin along the back of the other . The second male will then raise its head as high as possible . As they both do the same , the necks intertwine . When the heads <a href='drop_aux' title='2'><mark>are</mark></a>level , they turn towards each other and push . Their bodies intertwine as they switch positions . They become oblivious to everything else , continuing even after they fall off a surface or into water . Sometimes they intertwine and squeeze so tightly that their scales stand out from the pressure . They <a href='been_done' title='3'><mark>have</mark></a> also been observed to strike at each other with mouths closed . Occasionally , the combatants will tire and break off the fight by " mutual consent " , resting for a while before resuming once more . The event is settled when one of the two succeeds in pushing the other <a href='null_genetive' title='4'><mark>'s</mark></a>head to the ground and raising its own by 20 – 30 cm . In captivity , combat may occur four or five times a week until courtship and copulation ends . 
During peak sexual activity , males engage in combat . dis start with one male rubbing its chin along the bck of the other . The second male gon then raise its head as high as possible . As they both do the same , the necks intertwine . When the heads level , they turn towards each other and push . Their bodies intertwine as they switch positions . They become oblivious to everything else , continuing even after they fall off a surface or into water . Sometimes they intertwine and squeeze soo tightly that their scales stand outt from the pressure . They done also been observed to strike at each other with mouths closed . Occasionally , the combatants wgontire and break off da fight by " mutual consent " , resting for a while b4 resuming once more . The event is settled when one of tdatwo succeeds in pushin the other  head to the ground and raising its own by 20 – 30 cm . In captivity , combat may occur 4 or five times a week till courtship and copulation ends .