The article traces how, in the 1870s, Puerto Rico's sugarcane plantation owners imported the small Indian mongoose from Asia to control rats that were destroying crops and threatening the island's then-dominant sugar economy. According to the U.S. Centers for Disease Control and Prevention (CDC), the plan failed almost immediately because mongooses are active during the day while the cane-field rats were mostly nocturnal, so the rodent population went largely unchecked.
Freed from natural predators and with abundant food, the mongooses reproduced rapidly and spread across the island, becoming an invasive species. Their diet expanded beyond rodents to include birds, reptiles, amphibians and other small native species, disrupting local ecosystems and causing severe harm to native fauna. The CDC notes similar outcomes occurred on other Caribbean islands where the species was introduced.
What began as an agricultural fix turned into a lasting environmental problem that continues to affect biodiversity today. The article also notes the mongoose's negative impact later added a troubling public-health dimension, though it cuts off before detailing that aspect.