1. Environmental factors: Diamond argues that geography and environmental factors played a much larger role in determining which animals could be successfully domesticated. Animals that were suitable for domestication needed to possess certain characteristics like:
* Diet: Animals that could be fed readily available food sources were more likely to be domesticated.
* Growth rate: Animals that grew quickly and reached maturity early were more desirable for food production.
* Temperament: Animals that were docile and could be easily managed were more suitable for domestication.
* Social structure: Animals that lived in herds or flocks were easier to control and breed.
2. Limited availability: Diamond points out that not all regions had the same number or types of suitable animals. For example, North America lacked large, easily domesticated animals compared to Eurasia, due to the extinction of many species at the end of the last ice age.
3. Historical evidence: He presents evidence that different cultures, despite their variations in cultural practices, often faced similar challenges in domesticating animals. For example, the lack of domesticated animals in Australia or New Guinea wasn't due to cultural resistance, but rather the limited availability of suitable candidates.
4. Focus on adaptation: Diamond emphasizes that domestication is not a deliberate choice, but rather an adaptation to environmental constraints. If a culture lacked suitable candidates for domestication, it wasn't a failure of their culture but rather a consequence of their geographical location.
5. Convergent evolution: He points out that different cultures independently arrived at similar solutions when faced with similar environmental challenges. This suggests that biological and environmental factors were more influential than cultural differences.
In summary, Diamond challenges the notion that cultural differences were the primary reason for variations in animal domestication. He emphasizes the role of geography, environmental factors, and the availability of suitable animal candidates. He argues that cultural differences were not the driving force in determining which animals could be domesticated, but rather a consequence of the different environments in which these cultures developed.