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All In the Watershed

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Whale Wallows
Delmarva's hidden wetlands

Whale wallows, which are also referred to as Delmarva bays, kettles, sinks, or vernal pools, exist as part of a chain of wallows that extends in an arc from New Jersey to Georgia.

Practically invisible for much of the year, these depressions in the landscape, ranging up to 25 acres in size and found throughout the Delmarva peninsula, become a haven for a diversity of wildlife in the spring when rain and snow melt fill the wallows with water. Suddenly, the whale wallows are filled with life and provide a habitat for many endangered and threatened amphibians. Amphibians like the carpenter frog and the eastern tiger salamander thrive at these pools because there are no fish to prey on their eggs.

Over 2,000 of these water-filled potholes may exist on the Bay's Eastern Shore. And many are more than 15,000 years old.

Many stories account for the formation of these whale wallow wetlands. An old version, one that explains the name "whale wallows," tells the story of primeval whales that got stranded when the sea level resided. Unable to move, the animals wallowed in these areas, creating the depressions in the sand. Other explanations for the wallows vary from meteorites to the melting of large clumps of ice after the last ice age.

No matter how they are formed, the whale wallows are part of an extensive wetland ecosystem that creates a much needed habitat for amphibians like the carpenter frog and the eastern tiger salamander. Because the wallows are pretty much invisible for a large part of the year, some have accidentally been drained, built upon, or even paved over without anyone knowing that a prime habitat for amphibians was lost. Recent government programs, however, are providing better protection for these whale wallows and the animals and plants that depend on them.

References and further reading

Delmarva Bays: Natural Enigmasoutside link
An article about the whale wallows by Dorcas Coleman, Natural Resource, Spring 2001.