A Real Fairy House

Fairy shrimp. Photo: vernalpool.org

What's the difference between a pond and a puddle? And is there something that is classified in between? Even though it may sound like a riddle, those are questions that have answers provided by a very interesting creature - the fairy shrimp.

A puddle is created by rain or melting snow and doesn't last long. Evaporation and absorption into the ground happen quickly enough that very few animals can use puddles as a home. A mosquito might be able to complete transformation from egg to adult before a puddle dries up, but a bullfrog tadpole that takes over a year to mature would never make it. At the other end of the freshwater spectrum are ponds and lakes. These water bodies are often stream or spring fed and rarely dry out, so they are suitable habitats for fish, aquatic turtles, and bullfrogs - creatures that gladly munch on tadpoles or frog eggs.

But what about those bodies of water that fill up with autumn rains and stay wet until the heat of summer finally dries them out? Ecologists call these ones vernal (spring) pools or woodland pools. In the absence of hungry fish, vernal pools are the preferred, or sole, habitats for some animals. Spotted salamanders, marbled salamanders, and wood frogs are examples, but perhaps the most unusual vernal pool residents are fairy shrimp. Fairy shrimp are crustaceans whose relatives were marketed in comic books as novelty pets called Sea Monkeys. They are slow, graceful swimmers that filter feed as they travel upside-down in the water. While some species of fairy shrimp can grow to be seven-inches long, live in saline pools or even the Antarctic, our local species is limited to vernal pools, including our very own, misnamed Nanderwhere Pond.

So this spring, come take a short walk down the Turtle Trail, visit the pool, and you will see a real life fairy home and perhaps even some shrimpy fairies.

---Taro Ietaka, Director of Conservation & Land Stewardship