Radiation is known to cause mutations, and scientists wanted to know if there was a significant change in the mutation rate among alligators that lived out their lives in the radiated muck. But to answer that, they had to learn a lot more about parenting. Could any change in the mutation rate have been caused by the radiation, or could it simply be multiple partners, thus bringing many other genes into play?
You can't answer that question unless you know the identity of the daddy.
It now turns out that there may be some continuity in paternity among many of the gators there, so a change in the mutation rate could be a result more of radiation than multiple partners. That question will take a considerable time to answer, since females don't reproduce every year, but in time it may help scientists determine "if there is any safe level," Glenn said. "We are looking for a direct assessment of mutations between parents and offspring."
Glenn is a specialist in DNA analysis, and he and his colleagues will continue to capture alligators in several locations. It looks a bit primitive, but the researchers literally lasso the gators, pull them ashore, then hold them down so a needle can be inserted and DNA material extracted.
The female lays her eggs, usually around 30, in a nest. After the eggs hatch, the researchers extract DNA from the hatchlings and search for the signature of the male. Usually one, two, and rarely three males are responsible for the eggs.
The gender of the offspring, by the way, is determined by the temperature of the nest. Temperatures of 86 degrees produce females, and temperatures of 93 or higher produce males.
It's not entirely clear at this stage why the females in the Louisiana refuge tend to pick the same male from year to year. It's possible they just like the nest where they were successful the last time, so they return to the same site and find that the big guy is still hanging around.
This can go on for a long time, since the average longevity of an American alligator is 50 years. Some have lived beyond 70.
Alligators are found throughout much of the southeastern United States, and a few crocodiles live in the southern area of Florida. Gators tend to be shy, and usually retreat when a human approaches, but crocodiles can be very different.
"The principal differences between alligators and crocodiles are behavioral," Glenn said. "Crocodiles are like alligators on crack. They are hopped up, aggressive animals."
But all of these ancient reptiles can be dangerous. If they bite into an animal that is too strong to be pulled into the water and drowned, they may roll over quickly, pulling the arm or leg or whatever off the body of its prey, in a horrific maneuver called the "death roll."
But at least now we know they may also have a tender side. At least some of them. Some of the time.