Episode 137 – Polka Dot Tree Frog: A Light in the Darkness

“Today we’re talking about a tree frog with a bright personality. But more on that later.”

The tropical rainforests of South America hide all kinds of rare and fascinating animals – including a host of one-of-a-kind frogs. The polka-dot tree frog may look like your typical aimless amphibian but it actually leads a secret glamorous life full of glow sticks and rave battles. By day, he’s mild mannered Croak Kent. By night, he’s got a glowing personality. But sometimes being seen is how you avoid danger here in Life, Death, and Taxonomy.

Polka Dot Tree Frog Taxonomy

  • Anura are frogs and toads!
  • Hylidae are tree frogs.
  • Boana are gladiator frogs.
    • Frogs in the genus were once in Hyla but were moved in a major taxonomic revision. 
    • 70 species were moved into the family. And more frogs were discovered after that. 

Measure Up

Welcome to the beloved Measure Up segment. The official listener’s favorite part of the show! The part of the show when we present the animal’s size and dimension in relatable terms through a quiz that’s fun for the whole family. It’s also the part of the show that’s introduced by you when you send in audio of yourself saying, singing, or chittering the words measure up into ldtaxonomy at gmail dot com. We don’t have a measure up intro this week so that means we get to hear from an animal and Carlos has to guess what it is. 

  1. A rabbit
  2. A turtle
  3. A Squirrel
  4. A toad 


  • They are 3–4 cm (1.2–1.6 in) snout to vent.
  • 4 cm (1.6 inches)
  • How many polka dot tree frogs go into the longest chain of paper animals ever?
  • Hint: The chain depicted Yaguaretés, which are an endangered species of Jaguar, native to Argentina. The record was achieved by Kinder Natoons in Buenos Aires. 
  • 19,065 frogs. The chain was 762.63 m (2,502 ft).


  • Grey Tree frogs are about the same size and they weigh in at 0.25 ounces (7 grams).
  • How many tree frogs go into the weight of yaguarete?
  • Hint: Jaguar weight is relatively wide-ranging, but we’re going for the upper end of average. 
  • 13,737 frogs. A jaguar is 212 lb on the upper ends but they can be up to 348 lbs in rare cases.

Tree Frog Fast Facts

Jan Levan likes to live in subtropical and tropical swamps and forests. But they can also be found in urban areas and gardens.

The polka king and his cousins live in Central and South America and the Caribbean but Jan himself hails from Argentina.

Tree frogs are so named because they spend the majority of their lives in trees away from ground predators. They have a superior climbing ability when compared to toads. Tree frogs may come to the ground to mate and spawn, but some lay eggs in the water collected in bowl-like plants and never leave the leaves. 

Most tree frogs are smaller than toads because it helps them get around on thin branches without falling. Hylids have forward-facing eye-lids, which gives the binocular vision that helps them move around trees and find prey. 

Hylids lay eggs in a variety of locations, including traditional spots like ponds, but they may also lay them in trees and holes. Some lay eggs in sticky clusters on the sides of plants. When the eggs hatch, the tadpoles fall from the plant into the water below. 

Hylids are usually big time bug-eaters, feeding mostly on invertebrates. Larger ones may take on more robust prey. 

Major Fact: Light Bright Tree Frogs

There are lots of ways that light can be generated or interact with matter. Luminescence is the spontaneous emission of light that doesn’t result from heat (or a cold light).

There’s fractoluminescence, where light is produced by broken crystals.

Electroluminescence is when light is produced by an electrical current. There’s bioluminescence, where light is produced by chemicals in an animal or plant.

There’s even sonoluminescence, where light is produced by the sound of an imploding bubble (mantis shrimp). But let’s talk about a relatively new one to this show: photoluminescence.

There are two types: phosphorescence and fluorescence. 

The Two Types of Photoluminescence

With Fluorescence, photons (light particles) are absorbed at a certain wavelength and then emit those photons back out at a longer wavelength. 

For a long time, zoologists thought that only fish and invertebrates possessed fluorescence (again, the mantis shrimp). With the exception of some parrots.

But they discovered it in the polka dot tree frog back in 2017 when scientists shone an ultraviolet light on a few specimens they had collected in Argentina. The frogs can glow bright blue and green.

Unfortunately, you can’t see this glowing without the ultraviolet light.

Ultraviolet light (UV light or blacklight) is a form of electromagnetic radiation (light) that has a pretty high wavelength. So high, that you can’t see it.

You see kids, like diahrrea caused by some bad ceviche or filthy Venetian water, light comes in waves of varying intensity. 

On a Different Wave Length

The longest waves are AM radio waves that can be up to 100 meters long. The shortest are gamma rays, which are just 0.0001 nm and are more likely to kill you than turn you into the Hulk. 

We humans can only see wavelengths between 400 to about 750 nm. All the colors we’ve ever seen fall inside this spectrum, which means that almost all light is invisible to us.

Ultraviolet light is just that, super violet. It’s light with a wavelength that’s just barely too short for us to see. 

So, since the frog’s skin takes short wavelengths and turns them into long wavelengths, you can shine the invisible UV light on the frog, it absorbs it, and spits out a longer wavelength, which we can actually see. 

But how does the frog make its skin so fun?

Well, that’s thanks to some special juice in the frog’s skin. But the chemistry is super complicated so we’ll leave it at that. They can also leave fluorescent trails with their excretion.

Ending: So stay bright, play it cool, and pay some of that light forward like the polka dot tree frog here in LDT


Thank you to Casy for creating our theme song. To hear more of Casy’s music search Casy Michelle on Youtube

Thank you to Brian for creating the episode art. See more of Brian’s art at xNamaru on Instagram or Twitter.