Behind the beady eyes and nighttime “ribbit” lurks a fascinating creature. Frogs and toads hop a weird line in life. They take buffalo taxis and use dating websites. Throughout human history, froggy feet have also left memorable prints, having inspired everything from famous novels to some of the earliest pregnancy kits.

Centuries of studies could not plumb the depths of these amphibians’ limits. They still manage to surprise scientists with their ability to survive bizarre injuries and mutations.

10 Visible Hearts

The Hyalinobatrachium genus of frogs has transparent bellies. The unusual look soon earned the tiny amphibians the title of “glass frogs.” Found in Central and South America, the see-through skin of two species extends over the chest and show their hearts.

In 2017, a third glass frog was found to beat its heart openly at the world. Called H. yaku, it was a bit odd. A visible heart is already a weird thing to find in nature, but H. yaku also looked different than other glass frogs.

All other species take some thinking and perhaps a magnifying glass to tell them apart. H. yaku turned up in Ecuador’s trees sporting unique green spots and distinctive songs. They also had bright green to yellow-green skin. Interestingly, DNA tests showed that this frog was not closely related to the other two species with visible hearts.^[1]

9 Thousands Are Smuggled

Frog legs are considered a French delicacy. Several other European countries also consume the amphibian limbs. To meet the demand, the animals are imported from other places like Turkey.

The latter ships a massive number of frogs to Europe but also tightly regulates the trade. To ensure that the frogs are not exploited, only certain people may collect them. Hunters must be in possession of the right license and can only collect certain species at specific times of the year. This is simply too much red tape for poachers, who often gather the creatures en masse before selling them to overseas buyers.^[2]

In 2017, Turkish authorities caught five men attempting to do just that. When their minibus was stopped for a routine search, agents found about 7,500 common water frogs. The poachers confessed, and the kidnapped amphibians were released back into the wild.

8 The Match.com Frog

In Bolivia, one can visit the Museo de Historia Natural Alcide d’Orbigny. Inside this long-worded institute lives Romeo. This frog spends his days paddling around an enclosure and resting in the shadows. By species, he is a Sehuencas water frog, and by heart, very lonely.

After 10 years of croaking as romantically as he could, Romeo gave up in 2017. What his human caretakers already feared finally sank in—that he was the last-known frog of his kind. Even as Romeo’s calls fell silent, scientists continued their search for a mate.

In a creative move, they put Romeo’s profile on the online dating site Match.com. It raised enough funds to send researchers to the Bolivian cloud forest. In the past, it was full of Sehuencas water frogs. However, the usual suspects had decimated them—pollution, habitat destruction, and the deadly chytrid fungal infection.^[3]

The 2019 expedition found five Sehuencas. Only two were female, but one was the perfect age for Romeo. Should the couple find no romance, their two-legged Cupids will try in vitro fertilization.

7 They Have Kneecaps

Frogs have been dissected and studied for centuries. Yet, one fact managed to elude scientists until 2017. As it turns out, the little hoppers have kneecaps. Weird ones, too.

It all began with the discovery of sesamoids. These bony structures are embedded in tendons over joints, essentially making them kneecaps. They turned up in species thought to have none, which inspired an Argentinian team to try their luck with frogs.

Incredibly, they found something. A close look at 20 frog species revealed a primitive cap, not yet a sesamoid. It was more of a cartilage blob, soft and small. So tiny, in fact, that it was hard to see under a microscope. Rather than protect the joints from a blow, the squishy pads might exist to alleviate the constant stress that frog knees are under.^[4]

Although the primitive structures are not kneecaps in the modern sense, they suggest that the earliest caps did not evolve with the first tetrapods that crawled onto land. Instead, they came with amphibians.

6 Test Frogs Made Chytrid Global

To date, the chytrid fungus has caused 200 amphibian species to become endangered or extinct. How it spread across the world was unclear, but recently, a candidate hopped to the fore—the African clawed frog.

During the 1930s, doctors injected urine samples into females. If the pee came from a pregnant woman, a pregnancy hormone (human chorionic gonadotropin) made the frog ovulate. By the following morning, the tank would be full of eggs. Since the method was successful and repeatable, the frogs were in high demand and shipped around the world.

The pregnancy stick women use today became available in 1988. The frogs were no longer needed, and many were released into the wild. The global spread of the species made it a good candidate for the devastating fungus, but confirmation came in 2006 when clawed frogs in California were found to have chytrid. Most were healthy, a strong clue that the species is the original carrier of the disease.^[5]

5 Frog With No Lungs

Around 30 years ago, scientists encountered a frog so rare that only two specimens were known. Due to the rarity, dissection was not an option. Had it been done, however, something exceptional would have come to light. The creatures, Barbourula kalimantanensis, had no lungs.

In 2008, researchers went to Borneo to find some more. Unfortunately, the tiny amphibians loved remote jungle areas and, worse, rivers that were rapid and freezing. One diver developed hypothermia. But despite the hiccup, several frogs were found.

Nobody had any idea of the bizarre anatomy until they cut a few open. The stomach, spleen, and liver occupied the space normally reserved for lungs. There was also a mysterious piece of cartilage. Best of all, the species consumed oxygen through its skin.^[6]

Another bonus was how primitive they were. Researchers hope that the frogs can explain why lungs vanished from other ancient animals in the past and, each time, only in amphibians.

4 Buffalo Buffet

In northern Turkey, water buffalo roam the wetlands and pick up frogs as far as they go. Clever marsh frogs figured out that the hairy beasts attract flies. When buffalo come close, the amphibians clamber onto their backs and hunt down the insects. This also rids the buffalo of an irritating pest.^[7]

Before the researchers found this peculiar cooperation between the two species, nobody believed that amphibians could manage a partnership with a large mammal. Then researchers visited the Kizilirmak Delta near the Black Sea in 2012. Within a week, they recorded 10 individual buffalo carrying teams of frogs, with each group numbering up to 27.

Just to make sure that it was not a one-time freak show, researchers returned the following year. The same thing happened. Since both times occurred in the fall when frog numbers boom, this behavior could be a novel answer to the season’s intense competition for food.

3 Eyes Inside Frog’s Mouth

One day, two Canadian girls discovered a toad without eyes. However, a local journalist noticed that it seemed more aware of everything after its mouth opened. The reason sparked an enduring mystery. The animal had eyes, but they were attached to the roof of its mouth.

This was likely macromutation—a major change at birth and not something that evolved slowly over several generations. Although it takes small genetic changes to cause this phenomenon, the toad’s condition had never been seen before.^[8]

One cause of macromutation is a parasitic infection. In particular, the trematode worm causes amphibian hosts to sprout extra, deformed, or missing back legs. This was probably not the case. The eyeballs were healthy and functional, just in the wrong place. Despite the weirdness, it was worlds away from worm-induced limb abnormalities.

2 They Inspired Frankenstein

During the 18th century, an Italian doctor named Luigi Galvani electrocuted frog legs. When they moved, everybody got excited. Electricity was a newly discovered force—and poorly understood. As the experiments appeared to restore life, it spawned the practice of galvanism, the quest to reanimate the dead with electricity.

It was one of Mary Shelley’s inspirations for her 1818 gothic novel, Frankenstein. Another famous writer of the time, Lord Byron, was a close friend. Shelley once told him, “Perhaps a corpse would be reanimated; galvanism had given token of such things: perhaps the component parts of a creature might be manufactured, brought together, and endued with vital warmth.”^[9]

This was exactly what her main character, Dr. Frankenstein, did. Galvanism is now obsolete, but it helped to place a classic title on the shelves. All thanks to convulsing frog legs.

1 The Faceless Toad

In 2018, researchers walked around a Connecticut forest. They were on a mission to gather information about newts. Instead, they bumped into a freaky toad. More accurately, the amphibian kept bumping into their feet and everything around it.

The creature could not see. Its entire face was missing. At first, it seemed like magic was afoot. The adult American toad was healthy, and the terrible wound was covered with old scar tissue.

How did it survive?

Sadly, researchers believe that it perished shortly after it was found. The frog was probably hibernating when it suffered an attack that removed its nose, eyes, jaw, and tongue. For some reason, the predator never killed the sleeping toad.

Left in peace and without the need to eat, the remaining hibernation period allowed the amphibian to heal. However, it woke up blind and incapable of foraging. Even if it managed to avoid predators, the toad was doomed to starve.^[10]

Mentioning soundtracks of animated musical films, would likely immediately conjure up the image of Elsa strutting over the snow, singing “Let It Go”. Songs in kids’ films are not a new concept, but they have gotten better over the years to the extent where they are nominated for and win Academy Awards.

However, there are several criminally underrated songs in animated films that are just as good as the prize winners (sometimes even better).

10 “Great Spirits” – Brother Bear

Brother Bear was released in 2003 and tells the story of a Native American boy, Kenai, who can’t wait to become a man. However, when one of his brothers is killed by a bear, he immediately seeks revenge and is turned into a bear himself when he angers the spirits of his people. This profound story couldn’t have anything other than fantastic music to accompany it, and that it does.

The soundtrack was written by Phil Collins (who also wrote the songs for Tarzan) and some of the songs are truly excellent. A great example is “Great Spirits” performed by Tina Turner. Tina is no stranger to movie soundtracks, having also provided the title song to the James Bond film, “Golden Eye”.

9 “I See The Light” – Tangled

Tangled doesn’t only have many underrated songs, but is also an underrated film as Frozen seems to take precedence when it comes to favorite animated movies. The film tells the story of Rapunzel in a new and fresh way, with some great songs in the mix. These include “When Will My Life Begin”, “Mother Knows Best”, and “I’ve Got A Dream.”

The best by far however, is the song at the end of the movie when Rapunzel’s dream of seeing the floating lanterns comes true. She and Flynn are on a boat with the lanterns highlighting the scene from the background when they start singing, “I See The Light.” This epic song is performed by Mandy Moore and Zachary Levi and is still truly underrated.

8 “Deliver Us” – The Prince of Egypt

Dreamworks is behind the grand animated story, The Prince of Egypt, and while there are many awesome songs that form part of the soundtrack including “When You Believe”, some are surprisingly underrated as well. “When You Believe” is sung in the movie by the characters of Tzipporah and Miriam and a pop version was recorded by Whitney Houston and Mariah Carey in 1998. It also won the Oscar for Best Original Song.

Mostly overlooked however are the scores created by Hans Zimmer and Stephen Schwartz including the opening number of the movie, “Deliver Us”. Ofra Haza and Eden Riegel deliver a powerful vocal that sets up the story of the struggle of the Hebrew slaves.

7 “When We’re Human” – The Princess And The Frog

The Princess And The Frog is one of Disney’s most underappreciated gems. The movie tells the reworked tale of The Frog Princess in which a waitress named Tiana dreams of owning her own restaurant. She ends up kissing a prince who’d been turned into frog and ends up as a frog herself.

This film too features some great songs, two of which were nominated for Academy Awards but lost out to Up and Crazy Heart. The song that not many people talk about however is the fantastic “When We’re Human”.

Starting with the quip “enjoy your loneliness, my friend” this catchy tune definitely deserves more love.

6 “Lost in the Woods”- Frozen II

There is no doubt that Frozen has delivered some of the best songs of all animated films. “Let It Go” became a smash hit after the first film and the Idina Menzel-performed song won both a Grammy and an Oscar. It became one of the most globally recorded Disney songs and the international releases of the movie included at least 41 versions sung in different languages.

Menzel shone again in 2019 with the song “Show Yourself” that she performed as Elsa in Frozen II. While not quite as popular as “Let It Go”, the song garnered much acclaim.

There is a highly underappreciated ballad in the second movie however, sung by Kristoff (Jonathan Groff). Sounding like a nod to Chicago’s “You’re the Inspiration”, Kristoff belts out “Lost in the Woods” while he’s, you know, in the woods. There is even a nod to Queen in one scene during the song.

And while we’re at it, let’s never forget about “Reindeer Are Better Than People.”

5 “I’ll Make a Man Out of You” – Mulan

Mulan is another beautifully told story and is based on the Chinese legend of Hua Mulan. The film takes place during the Han dynasty in China and sees Fa Mulan impersonating a man in order to take her father’s place in battling a Hun invasion.

The action is set to a great soundtrack that includes songs like “A Girl Worth Fighting For”, “Honor To Us All”, and “Reflection.” One of the best songs to come out of this classic animated film is the inspiring “I’ll Make a Man Out of You.” It is performed by Donny Osmond & Chorus and plays as Mulan and her army are transformed into warriors. Stephen Schwartz was tasked with scoring the soundtrack of Mulan, and his ideas included a melody called “We’ll Make a Man Out of You.” He was however persuaded by Dreamworks to make music for the Prince of Egypt instead and the song was changed to “I’ll Make a Man Out of You”.

4 “When She Loved Me”- Toy Story 2

The Toy Story movies are hugely popular with kids and adults alike. Woody, Buzz Lightyear and their friends made a huge impression with the first film and this led to 3 sequels all with their own great soundtracks. The first instalment was the first animated film to be nominated for Best Original Screenplay and was also nominated for Best Original Song for “You’ve Got a Friend in Me” which is the most well-known song on the soundtrack.

There are quite a few sad moments throughout the Toy Story movies, with one of the most heartbreaking scenes being the one in Toy Story 2 when Jessie the Yodeling Cowgirl ruminates about being forgotten and given away by her owner Emily. The song that plays during this scene “When She Loved Me” is sung by Sarah McLachlan and is a true underrated tearjerker.

3 “Immortals” – Big Hero 6

During the trailers of Big Hero 6, the song “My Songs Know What You Did in the Dark” by Fall Out Boy could be heard playing throughout several scenes. And that wasn’t the last of the band’s songs in the movie either. Big Hero 6 follows the adventures of Hiro Hamada and Baymax and is the first Disney animated film to feature Marvel Comics characters.

It was the highest grossing animated film of 2014 and won several awards including an Oscar for Best Animated Feature. The soundtrack includes a thumper of a song by Fall Out Boy called “Immortals.” The song was written specifically for the movie and sold one million units. But despite its success, the tune still doesn’t make a lot of ‘best of’ lists.

2 “I Won’t Say (I’m In Love)” – Hercules

Development of the animated classic, Hercules, began in 1992 and the movie was finally released as a musical fantasy film in 1997. The film didn’t perform quite as well as its Disney predecessors and the soundtrack received mixed reviews. Some of the most recognizable songs to come out of the movie, is “Go The Distance” by Michael Bolton and “One Last Hope” by Danny DeVito.

The most under appreciated song on the soundtrack is “I Won’t Say (I’m in Love)” which is performed by Susan Egan, Lillias White, LaChanze, Roz Ryan, Cheryl Freeman and Vanéese Y. Thomas. The pop ballad is reminiscent of 1950s songs and its lyrics are about denying have romantic feelings towards a particular person; in this case Meg denying having feelings for Hercules.

1 “You’ll Be In My Heart” – Tarzan

Tarzan was the most expensive animated film ever made until Final Fantasy was released in 2001. It grossed $448 million worldwide and became the second highest grossing animated release in 1999, after Toy Story 2. The success of the film led to two sequels, a TV series and a Broadway show.

The songs on the Tarzan soundtrack were composed by music legend, Phil Collins and one of the tracks, “You’ll Be In My Heart”, won an Oscar and Golden Globe for Best Original Song. The soundtrack as a whole was the first to be recorded in several different languages to cater for different countries and Collins recorded French, Italian, German and Spanish versions of the songs. The album release of the soundtrack put Phil Collins back in the spotlight as it became his best-selling album in ten years. Strangely enough, despite “You’ll Be In My Heart’s” massive success, it is still one of the most underrated songs in an animated film.