Year of the Frog

2015 is officially Virginia’s Year of the Frog!

… did you know that frogs are considered by many conservationists to be the most imperiled group of animals in the world? … Frogs are important natural resources that deserve our attention. Because of their aquatic and terrestrial life stages, frogs are excellent indicators of environmental health and water quality. Source Credit: Virginia is for Frogs.

The preceding American Bullfrog (Lithobates catesbeianus) is the unofficial poster girl for the year-long celebration. This frog is probably female, as indicated by the size of her tympanum: the eardrum is about the same size as the eye in females; it is larger than the eye in males.

It’s easy to tell males from females in both the Green Frog and the [American] Bullfrog. Males have a yellow throat, and the tympanum, the visible round external eardrum located behind the eye, is much larger than the eye. Females lack the yellow throat and the tympanum is about the same size as the eye. Source Credit: Ask a Naturalist.

Mid-February is too early for frog-spotting in the mid-Atlantic USA, so I used an image from my archive of unpublished photographs. This individual was observed alongside the boardwalk in the hemi-marsh at Huntley Meadows Park on 12 September 2014.

Editor’s Note: A Tweet by regular reader Charlie Bale inspired me to add a pull quote from Virginia is for Frogs, the featured Web site in this post. Feel free to add comments to my blog anytime, Charlie!

Copyright © 2015 Walter Sanford. All rights reserved.

American Bullfrog

The preceding photographs show an American Bullfrog (Lithobates catesbeianus) spotted during a photowalk through the central wetland area at Huntley Meadows Park on 03 October 2013.

Late winter/early spring is the time of year when the amphibians that inhabit my favorite marsh begin to awaken from their slumber. Soon the air will be filled with the songs of singing frogs and toads … won’t be long ’til dragonfly nymphs start emerging from the water!

Copyright © 2014 Walter Sanford. All rights reserved.

American Bullfrog

The preceding photograph shows an American Bullfrog (Lithobates catesbeianus) spotted during a photowalk through the central wetland area at Huntley Meadows Park on 27 September 2013.

Frogs are very skittish sometimes; I remember thinking the frogs were behaving boldly for a few weeks around the time this photo was taken.

Copyright © 2014 Walter Sanford. All rights reserved.

Northern Watersnake (eating a frog)

The following photographs show a Northern Watersnake (Nerodia sipedon sipedon) eating an American Bullfrog (Lithobates catesbeianus), spotted along the boardwalk that goes through the central wetland area at Huntley Meadows Park.

The following slideshow features a time-series of five photos showing the predator slowly swallowing its prey. Frogs make an unmistakable distress call when they are in the jaws of a snake — once you’ve heard it you’ll never forget it!

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Human interest sidebar: “Peristalsis is an amazing thing,” commented one of the people watching the snake-eats-frog spectacle. I turned to the woman and said, “You must be some sort of professional biologist, because the word ‘peristalsis’ isn’t in the vocabulary of most people.” Turns out she is currently working as a veterinarian; her former job was at the Smithsonian’s National Zoo. Fascinating woman with a beautiful baby — hope to see her at the park again!

Copyright © 2013 Walter Sanford. All rights reserved.

Flying frog attacks dragonfly (revised)

The following short video clip shows a female Great Blue Skimmer dragonfly (Libellula vibrans) ovipositing eggs in the wetlands at Huntley Meadows Park on 24 July 2011. A male Great Blue Skimmer dragonfly is patroling the area to protect the female from other males (“hover guarding”).

Suddenly, an American Bullfrog (Lithobates catesbeianus) attacks the female dragonfly!

Question is, did the dragonfly survive the attack by the frog? The following time series of 10 still photos provides the answer.

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Watching the second video in real-time, it looks like a close call for the dragonfly — was she safe or out (game over)? Looking at an “instant replay” of the preceding time-series of still photos (shown below), it’s clear the frog missed “tagging” the dragonfly by a wide margin. For those of you scoring at home, the box score for the game of life looks like this: Dragonflies 1; Frogs 0.

The following photo gallery features annotated versions of the same time series of 10 still photos: the frog is highlighted in green (when necessary); the dragonfly is highlighted in blue.

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So what’s the life lesson learned from witnessing this extraordinary event? From an evolutionary viewpoint (i.e., survival of the fittest), it pays to have compound eyes that see in almost all directions as well as amazing aerobatic skills!

Tech Tips: Apple “Aperture” was used to save the preceding JPEG photos as still frames from the second video clip (GPS info copied from the video clip metadata to the JPEG photos). Apple “Preview” was used to annotate the second gallery featuring a time-series of 10 still photos.

Copyright © 2014 Walter Sanford. All rights reserved.

Self portraits

The following self portrait is entitled, “Kiss me and I’ll turn into a Prince!” I spotted an American Bullfrog (Lithobates catesbeianus) during a photowalk through Huntley Meadows Park. That’s my reflection in the water. (I was hanging over the edge of a boardwalk that goes through the wetlands.)

Compare and contrast the preceding photograph with the following photo, taken more than an hour later than the first picture. Yep, that’s my reflection in the water again (shown below). What’s different? Did you notice that one of two snails shown in the first photograph is missing in the second photo? Frogs eat snails … hmmm, I wonder.