There are many types of amphibians in our forest and in Washington because they love the moist environment! Amphibian is the combination of two Greek words – “amphi” which means “double,” and “bios” which means “life.” So amphibian means “double life,” describing the life cycle of amphibians which live in water and land for different parts of their life. They are able to live in the park because we have several wetland areas and most remain somewhat moist throughout the year. Amphibians were the first land animals with backbones (vertebrates) and have been around for 350 million years!
Amphibians vs Reptiles:
Both amphibians and reptiles are cold-blooded, which means they are dependent on outside conditions to regulate their body temperature. This is why many frogs hibernate. There are over 4,000 kinds of amphibians including frogs, salamanders, newts, toads, caecilians, and blindworms. There are over 10,000 types of reptiles including lizards, snakes, turtles, tortoises, alligators, and crocodiles.
Lifecycle of an amphibian
Amphibians go through incomplete metamorphosis which means that they don’t go through a “pupa” stage (like a butterfly), but gain new body parts as they grow. The larva (youth) look different from the adults.
Most amphibians begin their life as egg masses laid in water, usually in ponds attached to different types of sticks or plants. When they hatch, they stay in the pond as they grow their tails and legs, then emerge from the water as adults. Some amphibians will stay in water or near water as adults.
Body parts of a Northwestern salamander
Eyes: Salamanders have eyes on the side of their head. This wide range of eyesight helps them to see predators better. They can see above and underwater and have three eyelids to keep their eyes moist.
Legs: Amphibians have no claws on their toes.
Tail: Salamanders have tails their whole lives, unlike a frog whose tail grows back into their body as they age from larva to adult.
Gills: Juvenile salamanders have feathery gills outside of their body until they develop lungs as an adult. Some salamanders that remain in water as adults have these feathery gills their whole lives.
Amphibians in Bridle Trails
Amphibians are tricky to spot! They are adept at camouflage and stay in moist areas under leaves and logs. They breed in the forested wetlands of the park and in the drainage ditch along the powerline. If you do spot one, please do not touch them! Their skin can be easily damaged since it is so thin and some are poisonous (to avoid being eaten).
More information:
For more information on amphibians and reptiles in the Pacific Northwest, visit this Burke Museum webpage.
Download some coloring pages of salamander and frog life cycles.
Instead of their annual Amphibian Walk, IslandWood has created this Amorous Amphibians page.
Amphibian and reptile species found in the park here.
Photo credits: Gary Nafis, Jim Erckmann, Flickr (Seanin Og, Andrew DuBois), Wikimedia Commons (Connor Long), Portland Water District.