At the end of winter, just when you are thinking spring will never arrive, an ancient amphibian ritual begins to reassure us that spring is finally here. Wood frogs are an amazing amphibian that are found throughout the Washington DC area, the eastern United States, and most of Canada and Alaska all the way to the Arctic Circle.
To witness this froggie ritual, head outdoors as the days are reaching the 60 degree mark and the nights are rainy. There will be about a 2 week window when millions of adult wood frogs emerge from hibernation to sing and mate. You just need to take a walk into a wooded area where there are puddles of water, also know as vernal pools. These special pools dry up in most summers and fish are not able to live in them, so they are perfect for variety of amphibians to lay their eggs.
Male wood frog songs sound a bit like a quacking duck. As you approach a wood frog filled pool, their songs may stop, but if you sit or stand quietly, they will begin again. And it is amazing. Some pools may have hundreds of frogs right in front of you! During daytime, you will mostly see males. At dusk and nighttime, the more secretive females become active and available for all the males to court.
In just a few days, millions of gelatinous eggs will be laid by the female wood frogs. The eggs will hatch into tadpoles in about 1-4 weeks, depending on the weather and water temperature. The tadpoles will go through metamorphosis lasting about 2 months and then hop out of the pool as teeny frog-lets. The frog-lets disperse into the surrounding woodlands to feed on tiny insects and hide from predators. If they survive, they will return to the same pools as adults to repeat the cycle.
These small to medium sized, leaf colored frogs spend most of the winter buried under ground or at the bottom of vernal pools where they may actually freeze solid. It is this amazing freezing ability that has many scientists so intrigued.
Frogs are vertebrate animals. Just like people, they have muscles, bones, blood, and all the same internal organs (heart, liver, kidneys, etc…) too. This is why so many high school biology students dissect frogs, not to learn frog anatomy, but to learn human anatomy.
Wood frog anatomy is very similar to humans, just like other frogs. However, wood frogs have a very special physiology. Wood frog physiology allows ice crystals to form in their cells without rupturing the cell walls, as would happen in other vertebrate animals. And even more amazing, when they defrost, their bodies defrost from the inside to the outside!
Scientists are studying wood frogs to learn this secret and possibly figure out how to apply this ability to humans. Imagine if we could freeze humans, keep them in frozen hibernation during long space voyages, and then defrost the space-goers with no ill effects from the freezing. Kind of like Han Solo in The Empire Strikes Back!
Wood frogs are toadally wonderful!
Do you know a child who loves snakes? How about a child who loves exploring in the park and asks questions about every leaf, rock, and worm? Or a child who wants to know how an airplane flies or what makes the trash truck so loud? If so, you know a child who is interested in science.
While hiking in the cold winter woods the other day, I began thinking of all the family members, teachers, and other adults who encouraged my interest in snakes , reptiles, and the natural world when I was a child.
Although no one in my family loved (or even liked) snakes, my parents allowed me to explore the woods and swamps near my house, bring home and even the keep garter snakes and frogs I found. My grandparents brought me to reptile lectures at the zoo and baked cakes in the shape of snakes and lizards for my birthdays. When I was 9 years old, my grandma even snake-sat for me while I was on vacation – and my pet brown snake gave birth to over 20 live baby snakes while under her care!
Due to the encouragement of my family, I developed a life long love of and respect for nature and science. My goal in creating Reptiles Alive over 16 years ago was to inspire the same interests for science in other people – especially children.
Watching television shows or looking at a computer screens are two dimensional experiences that have little impact on our senses . Seeing a snake or lizard in a picture will not inspire the same excitement as seeing a real, living, breathing animal up close.
Imagine the difference between looking at a picture of an apple on a computer screen and holding a real apple in your hand. Which experience will give you a better appreciation for what an apple really is?
A child who comes home from a Reptiles Alive show wanting to learn more about reptiles, is a child who has been inspired to learn. An interest in snakes and animals can lead to interests in other aspects of science. A love of nature and animals can lead to compassion for all living creatures and our planet itself.
You are in the garden. As you bend down to pick a tomato, you see a: snake! Whoa – that snake has a triangular shaped head! Is the snake venomous?
Many people mistakenly believe that all snakes with triangular shaped heads are venomous. And not just people: a recent study in Spain has even shown that predators such as hawks and eagles will often avoid snakes with triangular heads! Valkonen, J., Nokelainen, O., & Mappes, J. (2011). Antipredatory Function of Head Shape for Vipers and Their Mimics PLoS ONE, 6 (7) DOI: 10.1371/journal.pone.0022272
The fact is, however, that many harmless snakes mimic the viper-like head shape when they are frightened. Harmless snakes including garter snakes, rat snakes, and water snakes will flatten their heads and bodies when they feel threatened. And snakes in the garden feel threatened when they see people.
So is there an easy way to know if a snake is venomous or harmless? No, not really. Herpetologists and snake experts learn to identify snakes using a variety of physical characteristics. There is also individual variation within species: albinism, melanism, and pattern variations that occasionally occur can cause confusion when trying to identify a snake.
At Reptiles Alive, we suggest that people just leave all snakes alone. If you leave snakes alone, snakes will leave you alone. That way it does not matter whether the snake is venomous or not – even venomous snakes will leave you alone if you don’t bother them.