Why are Barrington land iguanas endangered?

Hunting is one reason, a lot of people eat them. Another is capturing babies to be bred and/or sold in pet stores. Another theory suggests that global temperature change is responsible for the decline, because the sex of any reptile is determined by the heat the egg is kept at.

Further information:

Populations of marine iguanas decline regularly as a result of the weather phenomenon known as El Niño. El Niño, which brings drought conditions to the South Pacific, causes declines in food supply. In addition, predation by introduced species such as cats and dogs also poses a threat to the young marine iguanas. Many simply do not live to maturity.