LEHMAN TWP. — From the vantage point of the Eastern fence lizards waiting below, Renee Rosier had a giant hand and she was shaking a giant container.
But maybe No. 2501 and No. 0451, two siblings from the same egg clutch who share a bin and warming light in the animal lab at Penn State’s Wilkes-Barre Campus, didn’t care about that.
What did attract the attention of the two tiny creatures was a smattering of even tinier crickets and meal worms Rosier had sent tumbling into to their living quarters. Observers only waited a moment or two before the two lizards, each 5 weeks old and about the size of an adult’s little finger, darted to the bugs and had a snack.
Would lizards be so quick to rush for food if they were isolated rather than living together? And, would it make a difference if they lived in separate bins but could still see each other?
Those are the questions Rosier, an assistant professor of biology, seeks to answer in ongoing research that involves taking students into the field to collect females that are gravid, or about to lay eggs; raising, feeding and recording the behavior of the young for several weeks, and then returning them to the wild.
So far, she said, her research indicates the lizards, which are considered to be “sit-and-wait predators” become bolder if they can at least see one other lizard — perhaps because they perceive it as competition for food — but are more willing to explore new environments only if they have been able to fully interact with another lizard.
“We think of them as more primitive than mammals,” Rosier said. “Yet even with that primitive, reptilian brain, they still benefit from interaction.”
Her project has involved continual breeding of crickets to feed the lizards as well as testing the animals’ willingness to explore.
To test a lizard, Rosier stands behind a blind and uses strings to move a small gate, which allows the lizard to emerge into a controlled environment filled with shelters crafted from parts of flower pots.
“I give them 30 minutes to watch what they’ll do,” she said.
So, how did the scientist become interested in lizard behavior?
“If you ask my grandmother on my dad’s side, she’d say she saw it coming years ago,” Rosier said with a laugh. “I was the one who would run toward a snake or a frog when everybody else was running away.”
Rosier grew up enjoying outdoor adventures in rural Northwestern Pennsylvania, where it wasn’t too difficult to spot reptiles or amphibians.
The 35 Eastern fence lizards she has been studying in recent weeks are offspring of mothers that were collected in Huntington County in the middle of the state, and most of them have already been returned there. She plans to release the final 10 there soon.
“I’ll take them early in the day, so they’ll have time to get acclimated and find a spot that has both sunny and shady places,” Rosier said, explaining she’ll transport the lizards in a cloth bag and keep them cool to slow down their metabolism so they’ll experience less stress during the journey.
Then she’ll set them free in the wild, where they could grow to about 6 inches long and live out a 5-year lifespan.
She’s excited for them to return to nature, but slightly worried about how they’ll do on their own.
“I usually take a picture, wish them good luck, and tell them I hope to see them next year,” she said.