The protagonist is a warlord, who gains intelligence by consuming others of his species, which are reptilian. He works in a mine where he kills others and slowly gains power.
The planet is just grass because they have killed all other lifeforms. They breed by dropping sperm into the grass mindlessly. They hunt their young, which are dumb animal-like creatures that graze on the grass, and then eat them alive.
The screams of the "food" enhance the meal. There are some sort of games which are broadcast, and there are alien civilizations outside the planet. Possibly dogs are one of them?
Read an old paperback about 2006. It was possibly one in a series.