Pastoral wealth is defense-intensive because robbing other shepherds is easy and rewarding.

Evidence

Pastoral work is not labour intensive. Looking after 400 sheep is not very much harder than looking after 200 sheep. But pastoralism is defence intensive. What the shepherd does is protect the flock from jackals, hyenas, wolves, and above all from other shepherds. And the prospects of economic growth are very remarkable: all a shepherd needs to do in order to double his wealth is ambush another shepherd. — Diego Gambetta, Trust - Making and Breaking Cooperative…, 1920

Categorization

• XREF: The ease of predation (doubling wealth by ambush) is precisely the opportunistic behavior Hardin argues needs observability and sanctions to constrain—supports the reader’s causal chain.