Dr. David Cundall, a biological sciences professor from Lehigh University, was the speaker at the Oct. 6 Speaker's Series at Lehigh Gap Nature Center. His subject was amphibians at the Gap.
Some of the pictures in the Power Point presentation had been taken Oct. 5 when he was walking the Nature Center.
On the Chestnut Oak Trail he said that to see salamanders on what appears to be dry ground people have to flip the logs and rocks. A salamander that might be found in the forst is the Eastern Red-Back Salamander. Though they are dependent on water the 100 percent humidity that is found under rocks and logs provides enough. Although dependent on water, they seldom live near it.
If the weather gets sunny and dry they will go down into the ground - quite a long way if necessary. It is believed only 10 percent of them may be on the surface.
Since salamanders have no digging equipment they use the burrows of other animals to get underground and have been found at 13 feet.
The salamanders quickly repopulate an area when they are removed.
The Northern Slimy Salamander is twice as large as the Red-Back and are territorial.
Cundall said all salamanders have internal fertilization. The female will walk over the tail of a male and will snap her head down to stimulate sperm, which she has to place in her coloca, where it may be stored for up to a year. The female will lay only five to six eggs. The babies develop in the egg and when born may still carry part of the egg yolk to see them through to the stage where they can eat. Without maternal care they will not hatch.
Salamanders do not have lungs but exchange gas (oxygen) across the skin, which is why it needs moisture.
The third salamander found at the Gap is the Common Spotted. It breeds in spring near the Three Ponds. Sperm are deposited on the bottom of the pond and the female picks it up. The eggs are laid in clumps around a branch and develop as larva. They will have only front legs and can't eat for two or three days until the remaining yolk dissolves. Then the rear legs develop.
The Dusky Salamander is not near the ponds but prefers springs and seepage. They lay their eggs on land and glue them to the ceiling of a cavity. Cundall asked why? And answered his own question - That's just what they do. The Northern Red Salamanders behave in much the same way.
He said several times that the reason the salamanders behave as they do is unknown.
"We can gather information only from those on top of the ground. We haven't figured a way to get data from underground," Cundall said. However, on Long Island radio tracking has begun.
Switching to frogs, he said the Gray Tree Frog, Spring Peeper and Wood Frog all prefer the ephemeral (temporary) ponds. He said there are a lot on top of the ridge.
In the spring there are many Spring Peepers, but where are they now?
The Wood Frogs come out before the snow is gone. The males come first. If a pond is small there may be a die-off the following season.
Frogs may lay between 300 and 400 eggs.
All amphibians breed twice in their adult life.
One researcher found 33 turtles but few that had been marked in previous years.
A snake may consider a frog a good meal, but the frog hops and the footprints are far apart. The snake will have to sniff out the next footprint to follow the frog.
"All amphibians are dependent on water in different ways, it is not really dry or they would not be there," said Cundall.
Director Dan Kunkle asked how the heavy metals in the mountain soil affect amphibians. Cundall said it does not seem to and may be because it settles out in water.