Cuban crocodiles are a highly endangered reptile species – between 3,000-6,000 live in the wild. But because they have temperature dependant sex determination, biologists are helping conserve the species by manipulating the eggs’ incubation temperature to hatch males.
In addition to having a small range in the wild, the American crocodile is moving into the Cuban crocodiles’ territory. As interspecies breeding takes place and hybrids are reproduced, the pure blood line of the Cuban crocodile is in danger.
“As of January, 2010, there were only six males, twenty-three females and three unknown genders of captive Cuban crocodiles in zoos in the United States,” Barbara Watkins, reptile keeper at the National Zoo, shared with me. “There are many unpaired females in captivity because the populations are so low.” By facilitating the production of more males in captivity, reptile experts are hoping to bring this unique reptile species out of its endangered status.
On Sunday April 25th, National Zoo biologist Matt Evans and keeper Watkins observed a Cuban crocodile female building a nest in her habitat. This species makes a mound – in this case, made of mulch, dirt and leaf material – when she is ready to lay eggs.
Just a day later, this Cuban croc buried 22 eggs in her nest. The top egg was measured at 32 centimeters inside the mound, and the bottom of the clutch was 37 centimeters deep. Cuban crocodile eggs have an elongated shape, similar to snakes’ eggs.
Evans and Watkins took the eggs to incubate them.
“A Cuban crocodile’s sex is determined is by a specific temperature of the nest,” biologist Evans explained to me. “Our incubator has to be set from 90-90.5 degrees to produce males… So we have to monitor the highs and lows of the incubator at all times. The challenge is ensuring that we are keeping a constant temperature.”
Anything lower or higher than the male incubation temperature will result in female Cuban crocs. These eggs will incubate for 60-90 days before they hatch. This species is extremely aggressive – cannibalism has been reported – so by carefully monitoring these eggs, the National Zoological Park keepers will work to protect the baby Cuban crocodiles as they hatch, grow and feed.
“Right now we’re going to raise these crocodiles once they hatch… and we hope to send out the males so they can be part of breeding populations in zoos in the United States. Our Species Survival Plan coordinator provides us with recommendations as to which animals should be paired together genetically so we can keep populations pure and sustainable for the long-term,” says Evans.
View photos of “Rarest of the Rare” species named.