The game I chose to use is Primal Carnage Extinction and I listened to its many sound effects.

Roars, No they don't loop, they are around 1-6 seconds long, sound effect
Bite/attack sounds, don't loop, are all under 3 seconds, sound effect
Gun shots, do not loop, about .5-2 seconds, sound effect
Eating sounds, they do loop, are between 2-7 seconds, sound effect
Heavy breathing, loops, around 3 seconds, sound effect
FlameSaw fire, loops, base sound is about 2 seconds, sound effect
FlameSaw's saw, loops, 2-3 seconds, sound effect  
Idle, loops 1-3 seconds
Reloading, do not loop, 2-5 seconds, sound effect

Birds, do not loop, 1-5 seconds, foley sound
Outdoor ambiance, loops, foley sound
Light fixtures, loop, 5 seconds foley sound
Rain, loops, 10 seconds, foley sound
Wind, loops, 5-10 seconds, foley sound
Footsteps, do not loop, less than 1 second, foley sound
Clothes moving, do not loop, under 1 second, foley sound
Electricity, loops, 3 seconds, foley sound
Lightning, does not loop, 2-4 seconds, foley sound
Human talk, do not loop, 1-3 seconds, foley sound
Bushes, do not loop, 1-2 seconds, foley sound

The intro music: loops, about 60 seconds, composition
Battle music: loops, 10- as long as you are in combat, composition