Teaming Up to Save Endangered Fiji Iguanas

Researchers have found several new species.

Fiji iguana
Fijian crested iguana (Malolo Island).

San Diego Zoo Wildlife Alliance

Fijian iguanas have been making a home at the San Diego Zoo for more than 50 years. The prince of Tonga gave the zoo six Fiji banded iguanas in 1965, and the first hatchling was born in 1981.

The institution has the largest colony of this endangered species outside of Fiji. And the zoo manages the Species Survival Program (SSP) for the species. That’s a program developed by the American Zoo and Aquarium Association (AZA) to help ensure the survival of threatened or endangered species in captivity through breeding, reintroduction programs, field conservation, and education.

About a decade ago, researchers at the zoo began investigating the genetic profiles of their animals. They saw that several of them didn’t quite look the same as the others.

“We noticed some of our animals appeared to be a bit different from each other and had characteristics of Fijian crested iguanas,” Kim Gray, curator of herpetology at the San Diego Zoo Wildlife Alliance, explains to Treehugger.

They wanted to see if their interesting animals could become an “assurance population,” which are colonies of critically endangered and threatened animals that are preserved in captivity so that species don’t go extinct.

“But acknowledging you don’t want to start an assurance colony with hybrids, we started by looking at the genetics of the animals we had and comparing that with animals at the Taronga Zoo [in Australia] and in museums,” Gray says.

“From here we wanted to start looking at better understanding the evidence that our genetics showed.”

Iguana Collaborations

Kim Gray with an iguana in Fiji
Kim Gray with an iguana in Fiji.

San Diego Zoo Wildlife Alliance

Using DNA sequencing, zoo researchers discovered that there was much more diversity in the unexpected hybrid animals.

“We thought we’d see species A and species B and maybe a hybrid, but what we saw was that there was a lot more going on,” Gray says. “Just like wherever there's an individual island, you see these birds, they look very similar, but on each island, it's a unique species.”

That’s what they were finding with iguanas. So in 2013, they began really investing time and resources. Gray and a team of experts went to Fiji to learn more while also sharing the knowledge they already had.

“We obviously have kept them here for a long time. And so we have all this expertise on how many eggs they lay, how to take care of the babies, what they eat, how to take care of them with specialized lighting, how much humidity they need. They don’t know that in Fiji and if we’re starting a program like an assurance colony in Fiji, we certainly have some expertise we could give them.”

The zoo researchers wanted to learn more about the habitats and the populations of the iguanas, as well as the threats the iguanas faced. They knew they were threatened by mongooses and cats, but there are also dangers from climate change, deforestation, and habitat loss.

“We don’t know anything in the wild,” Gray says. “All we know is how to take care of them here and what they like.”

Over the past several years, zoo researchers and their partners have performed field surveys and collected samples from about 200 iguanas on 30 islands.

Iguanas are found on about 10% of Fiji's 300 islands. There were three known iguana species there: the Lau banded iguana (Brachylophus fasciatus), the Fiji crested iguana (Brachylophus vitiensis), and the Fiji banded iguana (Brachylophus bulabula).

The International Union for Conservation of Nature (IUCN) classifies the Fiji banded and Lau banded iguanas as endangered and the Fiji crested iguana as critically endangered.

But the team found more than these known animals. Instead, they discovered there were individual species on each island. They’ve described four so far, and Gray says there may be up to seven more.

Watching Iguanas Thrive

Fijian iguana
Fijian crested iguana (Malolo Island).

San Diego Zoo Wildlife Alliance

Gray says researchers are working with rangers and communities to raise awareness of the iguanas and support their conservation.

“They're seen a bit like our bald eagle,” Gray says. “They typically don't eat them, they're revered a bit, some local villages have them as a totem kind of animal. And it’s on the five dollar bill. They usually are interested and very supportive of what we are doing.”

One interesting collaboration was with Ahura Resorts on Malolo Levu island in Fiji. Resort workers had found injured and baby Fijian crested iguanas that were thought to be extinct on the island.

The iguanas thrived likely due to a program to reduce the numbers of non-native feral cats, dogs, and rats that were preying on native animals.

“Inadvertently they created this sort of mini reserve for the last remnants of these iguanas,” Gray says.

Scientists worked with the resort to create a program to support the species and monitor the population. The resort has planted thousands of native trees to help with deforestation and to create a habitat to support the growing population.

Successful Searching

Kim Gray searching for iguanas
Gray (left) searches for iguanas in Fiji.

San Diego Zoo Wildlife Alliance

Gray describes with excitement her trips to Fiji and the challenges of searching for iguanas.

“During the daytime when you’re in a tropical forest, you cannot see them at all. You have no idea and they’re up 20-30 feet so we have to look at them at night with headlamps on,” she says.

They spend hours in the jungle, shining their lights back and forth, hoping they’ll see a little bit of white underside from their bodies or eyes in the beam.

Researchers are training locals on the spotting and recording techniques so they can continue to provide information on the animals.

There are now about two dozen banded iguanas at the San Diego Zoo with usually one male and two females on exhibit. The iguanas live about 25 years, lay about five eggs once a year, and prefer to eat fruit salad over insects.

“Ours will never go back to Fiji because they do have some hybridization,” she says. “ And we want to be really careful about when you do reintroductions, that you're not inadvertently mixing genetics or disease.”

View Article Sources
  1. "Iguana." San Diego Zoo Wildlife Alliance Animals & Plants.

  2. "How We're Helping to Save the Fiji Iguana." San Diego Zoo Wildlife Alliance.

  3. "Species Survival Plan Programs." Association of Zoos and Aquariums.

  4. San Diego Zoo curator of herpetology, Kim Gray

  5. Sanders, Anna. "Wildlife Conservation Society Launches Global Effort to Save Endangered Turtles." Audubon.

  6. "Fiji Iguana." IUCN Red List.