frog habitat

Question
Hi.
I live in Amarillo, TX.  I discovered a small brown frog (not tree frog) in my garden yesterday (now end of summer).  Probably a young frog, but I don't know.  I've only seen green frogs before this.  I thought a frog needed to live near water.  I've never seen a frog before away from water.  The nearest body of water (stream) from here is a couple blocks away (downhill).  Toads love to hibernate in our garden, but do frogs hibernate underground too?? I use stream water to water the garden, could there have been a tadpole in the water?  I really probably would have noticed a tadpole in the water if there were the case.
BTW, I have a question about the mechanics of toad hibernation deep underground if you know anything about toads.  In other words, how toads do it exactly.
Thank you.

Answer
Hi Steve,

Many frog species are capable of dramatic colour changes from bright green to dark brown depending on temperature, stress and other factors. Highly aquatic species hibernate buried in the bottom of ponds. Others like the treefrogs and various chorus/peeper frogs will hibernate buried in leaf litter and below logs. These species can survive away from water as long as there is access to some moist areas like leaf litter or morning dew. They do need a body of water to breed however.

There are not many frogs listed as ranging into your part of Texas. My first suspicion would be that you may have found a Great Plains Narrow Mouth toad which is actually a small species of ground dwelling frog. You are on the edge of their recorded range but animal ranges have been changing in the last few years as the climate alters.

A Spotted Chorus frog would be another possibility. They are in the Hylidae family of treefrogs but lack the prominent toe pads found in the genus Hyla. Chorus and Peeper frogs are often on the ground or in low level shrubs.   

http://www.herpsoftexas.org/view/frogs

http://en.wikipedia.org/wiki/Great_Plains_narrow-mouthed_toad

I have read more about the mechanics of hibernation in frogs then toads but imagine it is similar. Toads have the distinct advantage over frogs of being able to deeply bury themselves. Some species to the point where they are below the frost line.

The main mechanism with frogs is an increase in blood sugar levels which lowers the blood freezing point, acting essentially like an anti-freeze.