Taiwan Authorities Increase Efforts to Cull Invasive Green Iguanas as Their Population Has Exploded

By Masatsugu Sonoda/The Yomiuri Shimbun

13:42 JST, September 20, 2025

KAOHSIUNG, Taiwan — A surging population of green iguanas in Taiwan, an invasive species, is wreaking havoc on farms across the island, prompting authorities to intensify culling efforts with bounty programs.

So far this year, over 160,000 green iguanas have been culled, more than 300 times the total culled in 2016.

“There must be seven or eight in that tree,” one of two hunters said on Sept. 12 in Kaohsiung, southern Taiwan, as they aimed their guns at a tree outside a home. A metal bullet, about two centimeters long, struck a green iguana, which then fell to the ground.

In about 90 minutes, the hunters had culled 14 green iguanas — both adults and babies — around the area. “You have to aim for the head,” said a 54-year-old indigenous hunter. “If you hit them in the body, they’ll just run away.”

According to Taiwan authorities, green iguanas, which are native to Central and South America, were first imported as pets about 20 to 30 years ago. Some escaped or were abandoned and have since multiplied rapidly in an environment with no natural predators.

A female can lay about 40 to 70 eggs at a time, with an estimated 80% of the eggs hatching. Since baby green iguanas were first spotted in the wild in 2004, the species have expanded their habitat from the south to the northern parts of the island.

Green iguanas spend their days basking in the sun in trees. Adults can grow to be 1.8 meters to 2 meters long and live for 20 to 30 years. Their diet consists mainly of leaves, vegetables and fruit, and some red bean farmers have reported significant crop damage.

Last December, authorities established a task force to combat the problem. They educated local residents on green iguana behavior and how to differentiate between males and females. A total of 14 hunting teams were formed, including indigenous hunters. Currently, a bounty of 250 New Taiwan dollars, or about ¥1,200, is offered for larger specimens, marking a major escalation in culling efforts.

While the authorities had planned to cull 120,000 green iguanas this year, officials say the number reached 160,625 as of Aug. 26, a 300-fold increase from the 527 iguanas culled in 2016. “We are focusing on eliminating females,” said an official. “We hope to curb the impact on agriculture and the ecosystem.”