11 Colorful Facts About the Red-Eyed Tree Frog

Agalychnis callidryas, better known as the red-eyed tree frog, is one charming amphibian. With bright red eyes, colorful sides, and an extremely expressive face, it’s hard not to be captivated by this wonderful frog. But no animal should be defined by good looks alone—so we talked to Don Boyer, Curator of Herpetology at the Bronx Zoo, to find out more. 

1. They've been around for millions of years.

Frogs, in general, are a pretty old bunch. Fossils show that frogs have been around for hundreds of millions of years; red-eyed tree frogs specifically emerged roughly 10 million years ago. 

2. Red-eyed tree frogs are masters of disguise. 

These amphibians are arboreal, meaning they spend a lot of time hiding in the trees. The frogs live in tropical lowlands in Central America and northern South America, and though one might think that its bright red eyes and blue and yellow markings would put the amphibian in danger, the crafty frog actually uses its flashy colors to its advantage. 

When seated on a leaf, the red-eyed tree frog tucks its legs in close to its body and closes its eyes to hide—but when they sense a predator, they open their eyes and jump away, exposing a whole slew of dazzling colors. Some scientists believe that this sudden burst of color can startle animals and throw them off guard, but a more popular theory is that it helps the animal get back into hiding. "If you startle a white tailed deer, the first thing it does is flip up its bright white [tail] and you see that, but as soon as it stops running, the tail drops back down and it blends in with the surrounding environment," Boyle explains. "As a predator, you’re looking for that bright blue/yellow contrasting coloration, [but] now that the frog has landed and it just looks like a big green blob on a leaf, you may not detect it." 

3. Night is the best time to spot them. 

During the day, the red-eyed tree frog hides its colors and sleeps stuck under leaves, where it blends into the foliage perfectly—sometimes, the frog will even have tiny yellow spots that resemble leaf blemishes. 

“We have an exhibit of them at the [Bronx] zoo and sometimes—right in front of people—they’re sitting on a leaf and they’re just tucked up sleeping, and people are like ‘well there’s nothing in here,’ or 'I don't see anything,'” Boyer says. “And you’re like ‘well there’s a frog about a foot from your head!’” 

At night, when they're less at risk of becoming a meal, the frogs are much more active; they spend the time hunting for insects. 

4. They’re somewhat poisonous. 

Tree frogs rely more heavily on their camouflage for protection, but they do have some toxins in their skin. This poison isn't exactly dangerous, but it does leave a bad taste in some predators’ mouths. “I don’t think there’s animals that necessarily would die from eating them, but I think some species probably don’t eat them because they don’t taste the best,” Boyer says. 

5. A special trick helps them eat faster. 

If you've ever seen a frog eat something, you might have noticed they close their eyes. Like most frogs, red-eyed tree frogs use their eyes to help swallow. Their tiny teeth hold the insect in place, and they retract their eyes into their body to push the meal down their throats. While they can swallow without the extra push from the eyes, it helps expedite the process so they can get moving. 

6. Male tree frogs use vibrations to ward off competition. 

When marking territory, males will shake their perch violently. The vibrations tell other males that the area has already been reserved. Scientists used a miniature seismograph to verify that the shaking branches were due to the frogs’ movements and not the wind. The vibrations travel about 1.5 meters, giving the male frogs a good amount of personal space. 

7. Mating season is like a big singles bar.

Mating season generally lasts from fall to early spring. Males climb down from their trees and gather around bodies of water; once each finds the perfect location, he'll start calling, at which point the females will descend from the trees and respond to the calls. “The breeding aggregations are pretty impressive,” Boyer says. “I’ve seen breeding aggregations of red-eyed tree frogs in Costa Rica and you can have literally hundreds of frogs around a body of water.” 

8. Females take the males for a ride. 

Once the female has selected her mate (it’s unclear what the deciding factors are, but it’s likely a mixture of size and call), the pair will go into amplexis: the female will carry the male around on her back for the course of the egg laying process. After the male hops on, the female draws in water that she uses to lay her gel-like eggs. After she lays her eggs on the bottom of a leaf, the male fertilizes them externally. 

“You can almost guarantee the eggs you fertilize will be your offspring unless another male wrestles you off—and some clutches do have multiple sires,” Boyer says. “But the idea here is that if you’re male, you can go into amplexis with a female and you can try to ensure that those eggs laid will be your eggs.” 

9. Tadpoles can hatch early.

Red-eyed tree frog eggs are laid under leaves that loom over water, so that when the eggs hatch, the tadpoles can fall directly in. These frogs-to-be generally hatch about a week after being laid, but they can emerge sooner, after just four or five days, if their survival depends on it. Because some species of snakes and wasps like to dine on the jelly-like eggs, the tadpoles are equipped with a special defense plan: If they detect movement or vibrations, they hatch prematurely and make their escape. 

10. It takes a while for them to grow up. 

It takes a red-eyed tree frog one to two years to reach maturity, depending on how much they eat. The frogs are usually about 1.5 to 2 inches long, and females are always larger than the males (a necessity for giving those piggyback rides). The frogs usually survive about 5 years in the wild, but can live much longer in captivity. 

11. Scaling wet leaves is no problem.  

These crafty amphibians can defy gravity and cling to leaves, sticks, and even glass. Frogs’ feet are not entirely flat: If you look at them under a microscope, you would see hexagonal nanopillars, which, Boyer says, “stick out [and] fit into irregular surfaces very well.”

In between each pillar, there are channels that allow mucus to flow. This gives the feet a wet adhesion. Using both friction and that adhesion, these frogs can stick to almost any surface—especially anything moist. 

All images courtesy of iStock unless otherwise stated. 

Mark Ralston, AFP/Getty Images
How a Hairdresser Found a Way to Fight Oil Spills With Hair Clippings
Mark Ralston, AFP/Getty Images
Mark Ralston, AFP/Getty Images

The Exxon Valdez oil tanker made global news in 1989 when it dumped millions of gallons of crude oil into the waters off Alaska's coast. As experts were figuring out the best ways to handle the ecological disaster, a hairdresser from Alabama named Phil McCroy was tinkering with ideas of his own. His solution, a stocking stuffed with hair clippings, was an early version of a clean-up method that's used at real oil spill sites today, according to Vox.

Hair booms are sock-like tubes stuffed with recycled hair, fur, and wool clippings. Hair naturally soaks up oil; most of the time it's sebum, an oil secreted from our sebaceous glands, but it will attract crude oil as well. When hair booms are dragged through waters slicked with oil, they sop up all of that pollution in a way that's gentle on the environment.

The same properties that make hair a great clean-up tool at spills are also what make animals vulnerable. Marine life that depends on clean fur to stay warm can die if their coats are stained with oil that's hard to wash off. Footage of an otter covered in oil was actually what inspired Phil McCroy to come up with his hair-based invention.

Check out the full story from Vox in the video below.

[h/t Vox]

A New Chew Toy Will Help Your Dog Brush Its Own Teeth

Few pet owners are willing to sit down and brush their pet's teeth on a regular basis. (Most of us can barely convince ourselves to floss our own teeth, after all.) Even fewer pets are willing to sit calmly and let it happen. But pet dental care matters: I’ve personally spent more than $1000 in the last few years dealing with the fact that my cat’s teeth are rotting out of her head.

For dog owners struggling to brush poor Fido’s teeth, there’s a slightly better option. Bristly, a product currently being funded on Kickstarter, is a chew toy that acts as a toothbrush. The rubber stick, which can be slathered with doggie toothpaste, is outfitted with bristles that brush your dog’s teeth as it plays.

A French bulldog chews on a Bristly toy.

Designed so your dog can use it without you lifting a finger, it’s shaped like a little pogo stick, with a flattened base that allows dogs to stabilize it with their paws as they hack at the bristled stick with their teeth. The bristles are coated in a meat flavoring to encourage dogs to chew.

An estimated 80 percent of dogs over the age of 3 have some kind of dental disease, so the chances that your dog could use some extra dental attention is very high. In addition to staving off expensive vet bills, brushing your dog's teeth can improve their smelly breath.

Bristly comes in three sizes as well as in a heavy-duty version made for dogs who are prone to ripping through anything they can get their jaws around. A Bristly stick costs $29 and is scheduled to start shipping in October. Get it here.


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