Summer Friends

I know it's mid summer when these little guys make their appearance on my front door.





My whole family enjoys these friendly little frogs - the Cope's Gray Tree Frog. This little guy is one of two almost identical tree frog species in Minnesota - the other being the Eastern Gray Tree Frog, and they are really only distinguishable by their call (which are still very similar), the black markings (or lack thereof) on their backs, and by chromosomal analysis. Since I don't feel like trying to scrape a bit of cheek cells off this little guy (or trying to obtain a blood sample), I am using my expert (not) observational abilities, noting that my friend here does not have black spots on his back, and that his trill is fairly fast (and can be compared HERE), and am therefore calling him a Cope's Gray Tree Frog.

But really, his name is not the most interesting part about this little frog. These are amazing creatures! As would be expected by their name, the Cope's Gray Tree Frog live in trees surrounding wetlands, prairies, grasslands, and Oak savannas. They have been found to hunt at night around lighted buildings on the outskirts of towns or around rural homes (which is why I have them on my front porch in the evening and morning - apparently, the hunting is good by my front door - and is also the reason we have to abandon the spot by mid summer lest we get eaten alive by hungry mosquitos).

The Cope's Gray Tree Frog breeding season is from May to July, and as with all frogs, they require a wetland to mate, lay eggs, and for tadpoles to live in for the first weeks of their lives. This brings us to an important point. Many wetlands in our area are becoming compromised by new homes being built and dirt being filled into them to allow for better building pads, but also by residents of these homes who stock their high quality wetland with fish, because they think that's what's supposed to be there or because they want to be able to go fishing in their own back yard. While fun for the fishermen, this can have catastrophic effects on all the frogs (and other amphibious creatures) in this community. Stocked fish have been shown to predate up to 94% of native wetland creatures, including the Cope's Grey Tree Frog, leaving the wetland a barren, fish filled waterway. The moral of the story here: if there aren't fish in your pond, wetland, or small lake, DON'T PUT THEM THERE. Wetlands are not just a flooded prairie. They are a breeding ground, a sanctuary, and a life giving haven to many of Minnesota's native wildlife, and they are fragile ecosystems that can be destroyed with the slightest human interaction.

Okay, now that I've said my piece on that, I want to share the most interesting part about the Cope's Gray Treefrog...

Living in Minnesota, it gets darn cold in the winter. What's an amphibious creature to do when it gets to be -10 degrees F? These frogs have an amazing ability to produce glycerol - and when it gets cold out, it circulates through the cells to prevent ice crystals from forming. Then, the frog freezes, it's heart stops, circulation stops, the frog stops breathing, and it spend the rest of the winter in a suspended animation state! When spring arrives, the frog slowly thaws, and thanks to the glycerol, all the cells are intact, and the frog heads back up the tree (and into the wetlands) to continue it's life.

How about some more pictures?



I think what I like most about these little guys is that they can change color depending on the temperature. They can go from grey (thus the name), to brown, black, tan, or even green within a few minutes. And the toes! I love their long sticky toes.





They make a mucos on their toes that allows them to stick to nearly any surface - even glass! It makes me happy when I wake up in the morning and see tree frogs crawling up my windows.



If you'd like to read more about the Cope's Gray Tree Frog, there's a great page HERE and HERE. Thanks for reading!