Female alligators aren't nearly as promiscuous as some members of the animal kingdom and typically mate with the same males for many years, according to the results of a 10-year research project at Savannah River Ecology Lab.
"It was very much a surprise," said assistant research scientist Stacey Lance, a member of the team that studied hundreds of gator nests in Louisiana's vast Rockefeller Wildlife Refuge.
Their findings, published recently in Molecular Ecology, show that up to 70 percent of the female gators choose to remain with the same male year after year.
The report amounts to the first evidence for partial mate fidelity in any crocodilian species -- and reveals a similarity in mating patterns between alligators and bird species. Crocodilians are the sole surviving reptilian archosaurs, a group of ancient reptiles that includes dinosaurs and gave rise to birds.
"In this study, by combining molecular techniques with field studies we were able to figure something out about a species that we never would have known otherwise," Dr. Lance said. "Hopefully, future studies will also lead to some unexpected and equally fascinating results."
The study site has a huge American alligator population.
"Down there they have thousands upon thousands of alligators," Dr. Lance said. "We didn't think it would be likely, year after year, that these females would not only encounter the same males, but continue to mate with them."
The studies, which are also being duplicated with gators at Savannah River Site's Par pond, required a lot of time and effort, she said.
"They find the nests by helicopter. It's a huge part of coastal Louisiana, so it's done by air," Dr. Lance said. "When they see a nest, they throw a pole into the ground to mark it, and then they come back in and take the eggs and then hatch them in an incubator."
Once the baby alligators hatch, blood samples are taken and they are released. "We sampled hundreds of nests, and they've been doing this for many years."
The samples were shipped back to SREL, and data were gathered and interpreted in the genetics facility, she said.
In addition to Dr. Lance, the research team was led by Travis Glenn, Ruth Elsey and Tracey Tuberville.
Reach Rob Pavey at 868-1222, ext. 119 or rob.pavey@augustachronicle.com.
MORE INFORMATION
To read an abstract of the scientific article, go to www3.interscience.wiley.com/cgi-bin/home. Select "Publication titles" and search for Molecular Ecology. Click the first link in the list, then scroll to the bottom of the page.
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