Wateright cocoons & baby eaters

Eleanor Konik

Eleanor Konik

Professionally, I teach world history. In my downtime, I enjoy combining storytelling with my love of sharing obscure history and science.


I've been working on developing the snapper species a bit further. For most of their lifecycle, they're normally a mashup between axolotls and snapping turtles, but I was curious if there were any other traits I could pull from to develop the amphibious stage of their lifecycle. Frogs seemed like a good place to start...

Quick Facts

  • The Goliath frog of West Africa is world’s largest frog; it can weigh up to 7 pounds and grow up to 15 inches. They're so big they can build their own ponds out of rocks, which function as nests tucked into rivers and kept clear of debris to make guarding them easier.
  • A frog uses its eyes to drive food down its throat when it swallows by pushing them into the roof of its mouth.
  • The female Surinam toad can lay up to 100 eggs. These are distributed on her back, then her skin swells out around the eggs, encasing them in a honeycomb-like framework. Fully developed young toads push through the membrane protecting the toad's back after 12 to 20 weeks.
  • Frogs shed parts of their retinas, which seems to be caused by exposure to light after darkness. There’s a similar phenomenon observed in rats.
  • Tadpoles of Darwin's frogs are swallowed by a male frog as they hatch. In order to give the little amphibians time to develop, he keeps them in his voice sac for roughly 60 days. He then starts coughing up tiny, fully developed frogs.

Sound Starter

About 180 million years ago, frogs became the first land animals with vocal cords. They also have vocal sacs; skin pouches found on the male frogs that are filled with air. Some frog sounds can be heard from nearly 3 miles away; the balloon-like sacs work like megaphones to amplify sound.

Tree Secrets

Many frogs can jump more than 20 times the length of their body, propelled by their long legs. The red-eyed tree frog of Costa Rica leaps from one branch to another with help from webbing that spreads between its fingers and toes. Their feet also have tiny suction cups on the bottom, to help them stay up in the trees. The neatest thing, though, is how they have bright red eyes and blue and yellow stripes on the sides of their bodies, which they hide while sitting motionless for most of the day… and only reveal when under attack. The bright colors startle predators enough to give the frog time to get away.

Water Weight

Frogs are poikilothermic, which is to say cold-blooded. Their internal temperature can still be different from that of the surrounding air. In frogs, the most important thing is how saturated the air is. They have very permeable skins, so that if the air is moving reasonably fast, the water in their bodies evaporates. They can lose about 25% of their weight this way, before dying. After dying, they might still lose up to 50% of their body weight. (Warning: my read of the linked study is that it was pretty mean to the animals).

Waiting it Out

Frogs can enter a brumation state to survive the winter in colder regions. The only difference between brumation and hibernation is that frogs periodically come out of their inactive state to eat. In dry seasons, some frogs store water in their bodies – mostly in their bladders – during their dormant period, which can be as much as half the year. They also form cocoons during longer dry periods, to prevent water loss.

📗 If you found this interesting, you may also enjoy my previous newsletters about bats or lactating egglayers.

💚 If you learned something from this overview, consider forwarding it to a friend and encouraging them to sign up for more overviews of my research into obscure history and science.

🐸 Do you have a favorite fact or story about frogs? Please reach out — I'd love to hear about it, either via email or in a comment where other readers can see.


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