When it’s time to eat your own skin

Several years ago, I bought a couple hard polyethylene pond liners and dug two large holes in my clay and rock-filled back yard. I wanted to have a pond area and figured that two big tubs would be easier to manage and clean than maintaining an in-ground pond. So far, that has been the case except for the fact that I couldn’t keep any fish – a great blue heron managed to eat all the fish I had over the course of about 2-3 years.

That doesn’t mean my pond is not populated, however. Indeed, all the water sources in my yard have residents. Some are unwanted – for example, the mosquito larvae that I admittedly kill with mosquito dunk. The Cope’s gray tree frogs (Hyla chrysoscelis) have a preference for my rain barrels. Somehow they manage to crawl inside even when a lid is on and they deposit hundreds of eggs per season.

   

Fortunately, not all of the frog eggs hatch or my yard would be overrun and the sound in the evenings would be overwhelming. Even the half-dozen or so current adults manage to produce quite a loud concert series – I’m surprised neighbors haven’t asked me to do something to tamp down the sound!

I used to have bullfrogs in my container ponds but haven’t seen them this year. Instead, my neighbors have been lovely green frogs (Rana clamitans). One grew to a very large size and he was joined by two others of a bit smaller stature.

They aren’t very noisy, mostly croaking in the late afternoon. It must have been that sound that attracted another neighborhood resident whom I spotted one day sitting on a nest box next to the pond. The red-shouldered hawks (Buteo lineatus) have spent time watching the pond before when in the mood for frog legs; this was a young hawk who had obviously been in the pond as evidenced by his wet plumage.

The pond was quiet for a few days and I thought the hawk must have had a good meal. And then, slowly, the frogs began to emerge again. There are three that sit on the rocks surrounding the larger pond although one is a bit smaller. This makes me think the hawk might have gotten one but that a juvenile frog was now accompanying the larger pair.

   

When my pond “greenies” croak, they don’t seem to get very large inflated vocal sacs. At the NC Botanical Garden, fellow photographer Mary showed me a green frog that she had been photographing and he croaked a couple times. It went too fast to get a good shot so I offered to make him “talk” by croaking at him. My pathetic attempt at imitating him really was quite pitiful, but amazingly did evoke a response. His vocal sac didn’t get really large either though.

One day, I spotted one of the yard frogs sitting on a rock, opening and closing its mouth without making a sound.

 

When I looked more closely, it seemed to have some membrane hanging on its side.

Then I saw that it was partly in the frog’s mouth and the amphibian was tugging away at it. I wondered if he was sick.

It turns out that he was perfectly healthy and staying that way by eating his own skin! These amphibians regularly shed their skin because it would otherwise harden and make it difficult for them to absorb oxygen while underwater, where they spend a considerable amount of time. So periodically, they scrunch themselves together and then stretch to break the skin so that it can be pulled off, leaving supple skin behind to better enable the “breathing” method called cutaneous gas exchange.

But why do the frogs then eat their skin? It actually has many nutrients, including calcium and proteins. I have no idea if the skin has any taste and whether they enjoy ingesting it. It seemed to be a bit of a laborious process when I watched this frog go through the process. Added to that is the fact that they actually use their eyeballs to push food down their throats and you discover that our froggy friends have quite a unique digestive process!

 

Outside my yard, I’ve not seen too many frogs this year. There was a lovely little Northern cricket frog (Acris crepitans) out and about on one of my walks.

More recently, I’ve been seeing Fowler’s toads (Anaxyrus fowleri) in the woods and parks.

 

     

At the NC Botanical Garden, I had the chance to see some rather large tadpoles sharing a pond with smaller ones.

It was interesting to see that the tadpoles first develop their hind legs and then their front legs before eventually losing their tails.

Finally, one more type of interesting creature I’ve been observing lately on walks are land snails. They don’t really belong in a blog that is about amphibians but it’s unlikely I’ll be writing one about mollusks any time soon. So, I’ll leave you here with a few photos of what I thought were some snails with beautifully spiraled shells. Have a good day or evening!

 

 

 

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s