'Per head' means 'for each person' but it is also used for animals especially cattle. 'Per capita' means the same thing, though it is more commonly used in statistics and social sciences.

per head = per person It can also refer to anything that has a head. Example: per head of cattle per head of sheep

Per (each) head with pro meaning "per" or "for each", and capite meaning "head." Both words together equate to the phrase "for each head", i.e. per individual or per person. cowboy

They say, "per capita".