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Shedd Aquarium’s Iguana Research Trip – Series Post 3

Tagging iguanas for research in the Bahamas. Copyright John G. Shedd Aquarium

Tagging iguanas for research in the Bahamas. Copyright John G. Shedd Aquarium

Shedd Aquarium’s rock iguana research trip in the Exuma Islands is well underway. For the first four days, we have been anchored off cays in the southern area of the island chain to study endangered iguana populations. Here, we visit three breathtakingly beautiful cays. One is home to a population of iguanas that are visited regularly by tourists. The other two lack easy landing points for small boats, which means that far fewer people encounter the iguanas that live on these cays.
 Each morning, we wake aboard the R/V Coral Reef II and breakfast together in the boat’s common area. Once we prepare the day’s gear, it’s time to move off the boat and onto the research site. Although we’ve been under sunny skies, strong winds have made for rough, wet rides to and from the cays. We might look a bit strange in makeshift ponchos fashioned from garbage bags, but they do help us stay dry until we reach the islands.

The rugged cays also mean that we can’t pull our small boats ashore. Instead we flip over the side and trudge ashore carrying our nets, backpacks, and “iguana box” full of research gear. In order to access one island, we have to leap from the bow of the boat, cling to a sharp limestone cliff, and crawl up with gear on our backs–a hindrance to tourists indeed.

Leaving Shedd's Coral Reef II and heading to the research site for the day. Copyright John G. Shedd Aquarium

Leaving Shedd's Coral Reef II and heading to the research site for the day. Copyright John G. Shedd Aquarium

Working with rock iguanas on the unvisited cays requires patience and persistence. We often had to crouch, and even crawl, after iguanas at these locations, and they can move with surprising speed. Evolved to travel across this uneven terrain, they have the upper hand—as well as plenty of holes and hiding spots.

So how do we level the playing field? By working in groups. A single person acts as a spotter, never taking his or her eyes off an individual iguana so they can direct everyone else to circle around it. After we secure an animal, a rapid flurry of activity commences: we take measurements and draw blood, determine the animal’s sex, count ticks, collect samples for parasite studies, take photographs, and check for an identification tag. If we find one, it means we’ve worked with the same individual iguana in previous years. This has been the case for 44 of the iguanas that we’ve found this year. Finally, we release the iguanas at the original sites where we found them.

A curious rock iguana investigates our research materials. Copyright John G. Shedd Aquarium

A curious rock iguana investigates our research materials. Copyright John G. Shedd Aquarium

It’s often after midnight before we tumble into our bunks aboard the CR II. We’re too busy to stop before then: on these three cays alone, we’ve tagged and researched 101 iguanas in the last few days. Additionally, we captured twice the number of iguanas on the visited cay, than we did from the other two non-visited sites combined. Be sure to come along with us for the next leg of our trip, when we travel to the Exumas’ northern cays, where all of the endangered iguanas populations have regular contact with people.