When I play as a predator i do not know how to collect marine and alien trophies.

Somebody !!!HELP!!!

I do not know how to do this also!!!
Someone help me too!!!

I didn't recognise it

I do not know.

WHAT should I do?

You must use the secondary attack of the wrist blade to acquire marine heads. Kill the marine first and then aim straight to the marine head to get it. As far as I know you can't get the heads if they're already ripped off from their victims. So the head must still be in place.

yeah thats how,and its really cool when you do it

not usre bout alien skulls though........

yeah thats how,and its really cool when you do it

not usre bout alien skulls though...........

sz bout the double post my comp jigged

Yes, you put the crosshair on the Marine head and use secondary fire wristblade. The Predator will roar when it's successful. Using the Primary fire wristblade is best to kill and leave the head intact.
The Alien trophies are harder 'cause their heads come off so easy. Use the Pistol and aim at their lower body. This will usually leave the head attached so you can collect it as a trophy.