HAWAI'I'S ENVIRONMENT
Lizard losing out to brown cousin
By Jan TenBruggencate
Advertiser Columnist
Q. In the past few years, I've noticed more of an anole-type lizard in our gardens around the island of O'ahu. These resemble the color-changing anole but seem to be a permanently brown color. They're a lot faster than the other lizards and seem to be much more voracious and aggressive. At the same time I've noticed an absence of both the color-changing anole and the skinks. Is it my imagination or are these newcomers taking over? Where did they come from? Are they a threat to the environment?
— Herbert Yee, O'ahu
A. Your observations are both good and accurate.
The brown anole, Anolis sagrei, is indeed more aggressive than its cousin the green anole, Anolis carolinensis. They have similar bodies, although the green anole has the ability to change from green to brown to help it blend into its environment. The brown anole lacks this ability. The green has a longer snout, and the brown is a little stockier. Both grow to about 8 inches.
The brown anole is the more recent arrival and is from the Caribbean. Like many alien lizards, it was probably first brought as a pet that escaped or was released into the wild, where it readily reproduced.
In Florida, wildlife managers say they've seen evidence of the brown anole outcompeting the green anole for food and habitat, and have even seen the brown lizards eating newly hatched green anoles.
"They tend to eat anything they can get in their mouths that moves," said Neil Reimer, manager of the Hawai'i Department of Agriculture's Plant Quarantine Branch.
He said the brown is a more aggressive lizard than the green, and is outcompeting it in Windward O'ahu. He has not seen evidence the brown anole preys on skinks, but said he doesn't doubt that they compete for habitat.
Brown anoles are still restricted to lowland areas in the Islands, where they are not a threat to the native environment — yet.
"Once they move into the native forest, they could be. They would prey on native insects," Reimer said.
Another potential problem is the knight anole, Anolis equestris, which can grow to nearly two feet long and is becoming established on O'ahu in windward forested areas. It is illegal for Hawai'i residents to keep these lizards.
Sean McKeown's 1996 book, "Reptiles and Amphibians in the Hawaiian Islands," has good images of all three.
Jan TenBruggencate is on special assignment. If you have an issue, question or concern about the Hawaiian environment, reach Timothy Hurley at thurley@honoluluadvertiser.com, (808) 244-4880 or P.O. Box 156, Wailuku, HI 96793.
