32: Canyon Treefrog
I write to you from Arapahoe, Ute, and Cheyenne land. I am interested in learning about the different animals that live in the place where I was born. I want to mention that biological classification as taught by western science has its roots in racism, sexism, and transphobia – here’s a good explainer about why.
Today’s animal is the Canyon Treefrog (Hyla arenicolor), a small and adorable tree frog who lives JUST over the southern edge of Colorado but lives much more in the other Four Corners states, especially Arizona, where they are the most commonly found frog in the Grand Canyon. They are generally found in rocky canyons near riparian areas, but you probably won’t see them because they are extremely well camouflaged. Their name in Spanish is “rana”.
Despite their treefrog status, they live in places that often do not have a lot of trees, and instead enjoy perching on rocks during the day before moving back to the water in the evening to forage. As tadpoles, they are vegetarians, feeding on algae, but when they reach adulthood, they become carnivorous and eat small invertebrates.
Note their Latin name – “arenicolor” means sand-colored – and refers to their ability to change their skin to camouflage into their environment. The Tucson Herpetological Society has this to say:
“Color change in amphibians is governed by a hormone called melanocyte-stimulating hormone (MSH), which stimulates color pigment cells to change skin color. In the Canyon Treefrog pigment cells can be black (melanophores), yellow-red (chromatophores) or silvery (iridophores), all working together in what Hadley and Bagnara call a Dermal Chromatophore Unit. The white color of treefrogs in bright sun is due to reflecting platelets in the iridophores, which contain crystalline deposits lined up parallel to the skin surface. When the treefrog turns dark, it is because melanin has been dispersed into the epidermis above the iridophores from the melanophores that are located beneath them (Bagnara 1994)… Canyon Treefrogs can change more quickly from light to dark than vice-versa. In light-to-dark change, MSH is quickly dispersed into the blood stream, whereas in a dark-to-light change the process of producing and releasing MSH from the pituitary into the blood occurs more slowly.”
As a result each frog can have a very unique appearance at any given time to match the desert conditions they live in – after all, deserts are also shifting palettes of color and light.
They are also adapted to live in extremely dry climates, despite being, well, frogs. They have the ability to breed in the type of periodically-appearing waterways that characterize much of the southwestern USA.
I have a strong canyon treefrog memory not from Colorado (where I have never seen one), but from being a child at my grandparents’ ranch in southeastern Arizona. It must have been springtime (I was quite young and don’t remember the details very well) and there was one of those fantastic sudden and violent desert rainstorms. My dad and I had been out somewhere away from the main house and took shelter under an outbuilding. We emerged into the calm after the storm to puddles everywhere in the rutted dirt road that leads to the house and every single puddle had hundreds of tiny frogs making an incredible cacophony. There were so many that we had to be careful where we stepped to avoid killing them!