Diictodon was an herbivore. It would've eaten small bushes and tubers in the vast pangaean desert. Diictodon would fight with each other over the same food source, which is why both genders had tusks. Diictodons would pop out of their burrows, and scurry towards a bush before snatching some leaves and running away.
The sparse vegetation that diictodons hoped they would find when trying not to starve.