The already dwindling population of the critically endangered Sister Islands rock iguana has taken a serious hit with the recent deaths of two adult reptiles, one of which was full of eggs.

The iguanas were run over on South Side, Cayman Brac, on Sunday, 20 June, and follow two other such deaths earlier this month.

Members of a group dedicated to saving the Sister Islands rock iguana say they are worried for the embattled indigenous species, especially now that more people are visiting the Brac and Little Cayman with Cayman’s borders closed.

“I think the increase in visitors could be contributing to the issue as many people from Grand Cayman are used to only seeing green iguanas on the roads and thinking they should be run over,” group member Cassandra MacDowell told the Cayman Compass.

However, she added, “in Cayman Brac you will very rarely see a green iguana, and any iguana you see in the road is most likely a Sister Islands rock iguana”.

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Cassandra MacDowell, pictured here with a baby blue iguana during her volunteer work with the DoE. – Photo: Submitted

She said the group was extremely concerned about the native rock iguana population which, according to a Department of Environment survey in 2019, stood at 1,786 on Little Cayman, and fewer than 200 on Cayman Brac. This species of iguana is found nowhere else in the world, apart from on these two islands.

So far this year, seven rock iguanas have been killed on the Brac, and MacDowell said the group is trying to spread the word on their importance and “why we need to do more as residents to protect the species”.

The situation is equally challenging on Little Cayman for the indigenous animals.

Last year, 32 rock iguanas were killed on the island’s roads, where the speed limit is 25 miles per hour.

Red markers are placed on the roadsides in Little Cayman to show the locations where rock iguanas have been struck and killed by vehicles, and a running tally of deaths is posted on a signboard near the Edward Bodden Airfield.

According to the DoE’s 2019 survey, Little Cayman has seen a 39% drop in its rock iguana population since the previous survey in 2015.

While roadkill is a common problem, MacDowell said it occurs more frequently during this time of the year, which is why people need to exercise more caution when on local roads on Cayman Brac.

“It is breeding season for these iguanas, and that means that they are much more commonly seen, especially along the roadsides, as they are out looking for new nesting sites and breeding partners. That sometimes means that they will need to cross the road to find and locate a good nesting spot and [that] unfortunately leads to them getting run over,” she said.

Sister Islands rock iguana deaths (Cayman Brac)

  • As of 20 June, 2021: 7
  • 2020: 9
  • 2019: 11
  • 2018: 18
  • 2017: 8
  • 2016: 9
  • 2015: 8
  • 2014: 3
  • 2013: 2
  • 2012: 4

MacDowell pointed out that speeding is also a factor in the deaths of these animals, which are very large and easily seen.

“We do expect that a lot of these roadkills are due to reckless and inconsiderate driving, people just not paying attention, people not going the speed limit… A lot of these roadkill instances have been on South Side Road on Cayman Brac, which is not a very busy road and people tend to speed quite often there,” she said.

The speed limit is 40mph, and she said the group has seen multiple cars and big trucks going well over that speed.

“Nobody should be hitting any sort of iguanas or wildlife with their car, regardless of if it’s an invasive species or a green iguana or rock iguana. The best thing to do if you see an iguana in the road is to slow down, even if it is a green [iguana],” she said.

MacDowell encouraged Brac residents and those visiting to look out for the indigenous species, and if they do see one while driving, “it is best to stop and get the iguana off of the road”.

She said people should avoid touching the rock iguana but rather shoo it away, such as by honking the vehicle’s horn.

MacDowell urged anyone who encounters a dead rock iguana to report it, by calling 917-7744 on the Brac, and 925-7625 on Little Cayman.

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  1. Another critically endangered species ( see pillar coral with stony coral disease article ) with one important difference. We can curb this problem by simply driving slower. Please slow down on the Sister Islands.