A sagittal crest runs along the ventral surface of the braincase and served as an attachment for protractor pterygoidei muscles that moved the toothed bones of the palate.

Living snakes that have narrow gapes, including uropeltids, Anomochilus, Cylindrophis, and Anilius, have diets that are limited to smaller animals such as ants, termite larvae, annelids, and amphisbaenians and caecilians.

However, the presence of strong m. protractor pterygoidei muscles inferred from the sagittal crest of Sanajeh indicates that it was able to manipulate prey in its mouth like modern macrostomatans.

The presence of these features in Sanajeh shows that increased oral kinesis (movement of the mouth) and intraoral mobility (the ability to move the bones of the palate) preceded the development of wide gapes in snakes.

Sanajeh is likely to have had a nest-plundering feeding strategy, and it is possible that the snake consumed a large variety of prey items including the eggs of theropods and smaller reptiles, which are common in the Lameta Formation.

Accelerated growth rates and large numbers of hatchlings would have enabled titanosaurs such as Isisaurus and Jainosaurus to overcome the losses of predation by animals such as Sanajeh.