John Cancalosi / Group of gravid female Timber rattlesnakes (Crotalus horridus) basking before giving birth, Pennsylvania, USA, July.

John Cancalosi / Female Timber rattlesnake (Crotalus horridus) at nest site with newborn young, Pennsylvania, USA, September.

Doug Wechsler / American toad (Bufo americanus) crossing road at night in front of car headlights, Philadelphia, Pennsylvania, USA, March

Michael Hutchinson / Abstract apartment and office buildings, Philadelphia, Pennsylvania, USA

Doug Wechsler / American Toad {Bufo americanus} male calling, his vocal sac vibrations causing ripples in the water, Pennsylvania, USA

Niall Benvie / American alligator (A. mississippiensis) teeth. C. PY, USA. Pennsylvania

Doug Wechsler / Bullfrog male in garden pond {Rana catesbeiana} Pennsylvania, USA.

Tim Fitzharris / Dandelion (Taraxacum officinale) with bee covered with pollen, Pennsylvania

Gerry Ellis / Fall leaf pattern close-up, eastern hardwood forest, Allegheny National Forest, Pennsylvania

Gerry Ellis / Fall leaf pattern close up, eastern hardwood forest, Allegheny National Forest, Pennsylvania

Norbert Wu / Amazon River Dolphin (Inia geoffrensis) melon on forehead used for sonar, Pittsburg Aquarium

John Cancalosi / Timber rattlesnakes emerging from den {Crotalus horridus} Pennsylvania, USA