The genus of salamanders you are studying is one of the most diverse amphibian groups in California! Batrachoseps even has a special species only found out on the Channel Islands.

Batrachoseps is a member of a very large family of salamanders called the Plethodontidae, which originated (we think) in the Appalachian mountains of the eastern United States. The oldest fossils of this family are from the Miocene epoch. This period of time began about 28 million years ago and ended around 5 million years ago, and was a very warm period during which the first kelp forests and grasslands appeared. We can't say for sure how old Batrachoseps is, but a good guess would be somewhere between 5 and 8 million years.

The Desert Slender Salamander is an endangered species which inhabits a very restricted range in Southern California. The Salamander has only been reported from a small canyon on the east slope of the Santa Rosa Mountains! It is a great example of how difficult it can be to protect endangered species... Imagine what would happen to this species if someone decided to build houses in this canyon!

Batrachoseps species can be found all over California. The best way to find them is to go out in the middle of winter, when things are wet (maybe February) and turn over every rock and log you see. Under one of them will be a tiny salamander all curled up, maybe protecting its eggs. Batrachoseps are very slow, and it is OK to handle them as long as you are gentle and you keep your hands wet with dew from the grass. I usually find them in oak woodlands in the grass under the trees beneath large hunks of wood or bark, but of course you can find them in the desert as well.

When you complete your report, ask your family to make a trip up to San Luis Obispo or Cambria and hunt around on a grassy hill that has lots of oak trees.

I don't know how much they weigh, but they are usually only about 6-8 cm long, so it isn't much!

As you probably know, Desert Slender Salamanders are on the endangered species list - only about 500 of them are known to exist! Salamanders are amphibians, so they depend on water. Desert salamanders such as the Batrachoseps aridus are very vulnerable to changes in the local water. If the water goes away, so will they. I'm not sure how much they weigh, but they are very tiny - only 3-5 cm long (1.5-2 inches).

As far as I know, scientists do not know exactly when the Batrachoseps aridus evolved. They are so rare, that I doubt anyone has ever found a fossil of them so we can find out how old the species may be.The oldest salamander fossils ever found are 160 million years old - they were preserved in a volcanic ash in China. The Batrachoseps aridus is probably much younger - maybe just a few million years or less, but we don't know.