Jackals are like their human given nickname. They're actually avian based space pirates called Kig-Yar. They're above grunts and drones in the covenant hierarchy but below elites and brutes. They can be snipers which have the carbines or the beam rifles with the last one being worst. But you'll run more into the shielded guys. What's cool is you can pop them in the hand and they falter enough that you can then go in for the headshot.