Closer look at the Halo 4 Jackal

Notice that the jackals in these images are a lot more fierce looking, also their heads are more thicker and buffer were as before their head structure was a lot more thinner and their mouths were longer and had a "Beak" like structure.

There is a real major difference with the Halo 4 Jackals.

Here are some images of Jackals from previous games just to give you a better view of the differences they have.