Rare twin iguanas born

The birth of the twin blue iguanas boosts the Recovery Programme

They scrambled out of the box and into the bathtub on Tuesday, and when Fred Burton and Alberto Estevanovich leaned in to count them, they discovered an extra one. 

And so on Friday, the National Trust’s Blue Iguana Recovery Programme announced the birth of twins. The coincidence with Monday’s royal birth in London was purely an accident, but the occasion no less celebratory. With 14 new additions to “the blues” – from only 13 eggs – the captive population of Cayman’s emblematic creatures has reached 190, and each of the newborns appears happy, healthy and thriving. 

While iguanas are not normally named, they are measured, and the twins ranked slightly shorter and lighter than their 12 siblings. All, however, according to Programme Director Fred Burton, are expected to thrive. 

“The twins weighed in at 32 grams [1.1 ounces] and 31 grams [1.09 ounces],” he said. Length is measured twice – from snout to rear end and, independently, the tail, separable from the body. Both “snout-to-vent” lengths were 3.5 inches, but the heavier of the pair had a 6.7-inch tail, shorter than the other’s 7-inch appendage. 

By contrast, the other 12 blues weighed between 1.76 ounces and 1.9 ounces. Full-grown, however, the animal is hard to predict. 

“They really never stop growing,” Mr. Burton said, but laughed off the notion of monster reptiles rampaging through Japanese cities. 

He did not, however, anticipate a special feeding programme to ensure the pair’s growth, saying they all had hearty appetites: “We have to cut up huge numbers of flowers” to maintain their vegetarian diet, which includes leaves and berries. 

Their smaller size, however, is likely to delay their release from the breeding facility into the wild by a year as they catch up with their larger brothers and sisters. 

“Normally, we let them go when they are about two years old, but these will probably take another year,” the director said, but had no fears for their ultimate longevity. 

“Iguanas live pretty much as long as we do,” he said, and while records of wild reptiles are scanty, he cited a Texas zoo where the resident iguana died at 69 years old. 

“We don’t have a lot of information. We only have the ages of the iguanas we have known since they were youngsters. We started in 1990, and now it’s 2013. 

“All of them have very high survival rates, though. We have a sort of ‘blue finger’ with them,” the equivalent of a gardener’s “green thumb”, he said, crediting the gentle finesse of warden Mr. Estevanovich. 

Twins are unusual, Mr. Burton said, counting only two other pairs he has seen in Cayman. “The first ever was during Hurricane Ivan. The power was out and we had the eggs in incubators. We were a little concerned, but we kind of shrugged and said they’ll do fine.” 

Born right on time, after the standard gestation period of 69 days to 72 days, the smaller twin died, he says, unsuccessfully competing for resources with its sibling. 

“Normally, you have enough yolk for their welfare and development, but if you get twins, it can be a real race,” Mr. Burton said. The second pair were also disparate, “but we managed to coax the smaller one through”, and both survived. 

The Recovery Programme has 750 blues in the wild, spread between the Salina and Colliers reserves, and “they are looking absolutely great”, Mr. Burton said. 

“We don’t see them much,” he added, just because they roam hundreds of acres freely. In March, eight programme staff spent 18 days walking the 625-acre Salina Reserve, recording 441 “blues”. 

“We won’t go back to Salina for another three years, but we’ll go to Colliers in March” next year, he said, probing its 190 acres.  

The hope is that the population will eventually hit 1,000, gaining critical mass and self-sustenance, although the timing remains uncertain. 

“For two years to three years, I have been saying it will take two years to three years to be self-sustaining,” Mr. Burton said. “Let’s just say it ought to be soon. We will still need to manage them, though. The only reason they are sustained now is because of the breeding programme.” 

The 14 hatchlings’ mother, “Shreddie”, was named by her sponsors, Tim and Stephanie Dailey. The National Trust has dubbed their father “Peter the Foundling”. Iguanas are normally assigned only a code number indicating parentage, time date and place of birth.  

“But if anyone wants to name them, they can, and sponsor them,” he said. “A name is a big deal because they carry it around with them the rest of their life.” 

Presumably the Daileys paid the standard $1,000 charge for a name, and another $500 for an annual sponsorship, “just about what it costs to raise them”, Mr. Burton said. 

Already, he said, the programmne has had another set of births, 19 baby blues on 23 July. He and Mr. Estevanovich are also watching “another three boxes, but they are due quite a bit later”. 

According to a National Trust press release, a final question looms about the twins, and Mr. Burton hopes to answer it: “We don’t know if [they] are identical – they could be from a single embryo that split to create identical twins, perhaps sharing the same yolk.” 

Alternatively, they could be fraternal: “They could have started as two separate embryos which developed in the same shell, each with its own yolk. Maybe when they get older we will be able to see if they share any peculiar features, or perhaps test them genetically just for 
interest’s sake.” 


Warden Alberto Estevanovich takes a closer look at the new arrivals.