Buzz
Hidden behind those gleaming, round eyes and the familiar nighttime 'ribbit' is a creature brimming with intrigue. Frogs and toads lead a life full of strange adventures, from catching rides in buffalo taxis to hopping onto dating platforms. Their influence stretches throughout history, inspiring everything from iconic novels to even some of the first pregnancy tests.
Despite centuries of research, these amphibians continue to defy expectations. Their ability to endure bizarre injuries and mutations continues to baffle scientists.
10. Hearts on Display
The Hyalinobatrachium genus of frogs is known for its transparent bellies. This striking feature quickly earned these small amphibians the nickname 'glass frogs.' Found across Central and South America, the see-through skin of two species extends over their chests, revealing their beating hearts.
In 2017, a third species of glass frog was discovered, with a heart that beats in full view of the world. Dubbed H. yaku, this particular frog was a bit of an oddity. While seeing a visible heart in nature is rare enough, H. yaku stood out from other glass frogs in more ways than one.
Unlike other species, which require a closer look or a magnifying glass to distinguish them, H. yaku was easily identified in the trees of Ecuador due to its distinct green spots, unique calls, and vibrant green to yellow-green skin. Interestingly, DNA analysis revealed that this frog was not closely related to the two other glass frog species with visible hearts.
9. Thousands Are Illegally Traded
Frog legs are regarded as a French delicacy, but several other European nations also enjoy these amphibian limbs. To satisfy demand, frogs are imported from places such as Turkey.
Turkey exports a significant number of frogs to Europe, but the trade is heavily regulated. Only authorized individuals can harvest them, and they must hold the proper license. Additionally, only certain species can be collected at specific times of the year. This strict regulation is often too much for poachers, who frequently gather frogs in large quantities and sell them to international buyers.
In 2017, Turkish authorities apprehended five men trying to smuggle frogs. During a routine check on their minibus, agents discovered about 7,500 common water frogs. The poachers admitted their actions, and the stolen amphibians were returned to the wild.
8. The Match.com Frog
In Bolivia, visitors can explore the Museo de Historia Natural Alcide d’Orbigny, home to Romeo. This frog spends his time swimming around his enclosure and lounging in the shadows. Romeo is a Sehuencas water frog, but he’s deeply lonely at heart.
After a decade of attempting to serenade his would-be mate, Romeo gave up in 2017. What his caretakers had feared for so long came to pass—he was the last-known frog of his species. Even though Romeo’s calls eventually ceased, scientists kept searching for a companion.
In an inventive attempt to help, Romeo’s profile was created on the online dating platform Match.com. This sparked enough interest to fund an expedition to the Bolivian cloud forest, which was once home to Sehuencas water frogs. Unfortunately, pollution, habitat destruction, and the deadly chytrid fungus had wiped out most of the population.
The 2019 expedition uncovered five Sehuencas frogs. Of them, only two were female, but one was the perfect age for Romeo. If romance doesn’t bloom, scientists are prepared to try in vitro fertilization.
7. They Have Kneecaps
Frogs have been dissected and studied for centuries, yet one fascinating detail eluded scientists until 2017: these little jumpers actually have kneecaps—and some pretty strange ones at that.
The discovery began with sesamoids, small bony structures that are embedded in tendons around joints, essentially acting as kneecaps. These sesamoids were found in species previously thought to lack them, prompting an Argentinian research team to investigate frogs.
Surprisingly, they discovered something unexpected. A thorough examination of 20 frog species revealed a rudimentary cap, which wasn’t quite a sesamoid. It was more of a soft, tiny cartilage blob, so small it was difficult to detect under a microscope. Rather than acting as a protective cushion for the joints, these tiny pads likely serve to relieve the constant stress on frog knees.
While these primitive structures aren’t true kneecaps in the modern sense, they suggest that the first knee caps didn’t evolve alongside the first tetrapods that ventured onto land. Instead, they developed later with amphibians.
6. Test Frogs Made Chytrid Global
The chytrid fungus has caused 200 amphibian species to either become endangered or extinct, but how it spread across the globe remained a mystery until recently, when the African clawed frog emerged as a prime suspect.
In the 1930s, doctors used a curious method to test for pregnancy—injecting urine samples into female frogs. If the urine came from a pregnant woman, a hormone known as human chorionic gonadotropin would trigger ovulation in the frog, causing it to lay eggs by the next morning. This successful method led to a high demand for the frogs, and they were shipped worldwide.
The pregnancy test kits we use today became available in 1988, making the frogs obsolete. Many were released into the wild, and their global distribution made them an ideal candidate for spreading chytrid. The confirmation came in 2006 when African clawed frogs in California were found to have the fungus. Most of the frogs were healthy, suggesting that this species was the original carrier of the disease.
5. Frog With No Lungs
About 30 years ago, scientists came across a frog so rare that only two specimens were known. Due to its rarity, dissection wasn't an option, but had they proceeded, they would have discovered something extraordinary. The species, Barbourula kalimantanensis, had no lungs.
In 2008, researchers ventured to Borneo in search of more of these unusual creatures. Unfortunately, the frogs thrived in remote jungle regions with rapid, icy rivers, and one diver even suffered from hypothermia. Despite the challenging conditions, several frogs were eventually located.
The true nature of their anatomy remained a mystery until the frogs were dissected. Inside, the stomach, spleen, and liver took up the space typically occupied by lungs. There was also an odd piece of cartilage, and the most remarkable discovery: the species absorbed oxygen through its skin.
Another interesting aspect is how primitive they were. Researchers are optimistic that these frogs could provide insight into why lungs disappeared from other ancient animals, especially amphibians.
4. Buffalo Buffet
In the northern region of Turkey, water buffalo roam the wetlands, and they unknowingly carry frogs along for the ride. The crafty marsh frogs have learned that the buffalo attract flies, so when these large creatures approach, the frogs hop onto their backs and feast on the insects. This arrangement also helps the buffalo by removing a bothersome pest.
Before researchers observed this unlikely partnership, no one imagined amphibians could form a bond with a large mammal. In 2012, they visited the Kizilirmak Delta near the Black Sea and within a week, spotted 10 buffalo each carrying a team of frogs, with some groups numbering as many as 27.
To confirm that this wasn't just a one-off occurrence, researchers returned the next year, and once again, the same behavior was observed. Since both events took place in the fall, a time when frog populations surge, this behavior may be a clever strategy to cope with the intense competition for food during the season.
3. The Faceless Toad
In 2018, while gathering data on newts in a Connecticut forest, researchers encountered an unusual sight. They weren’t expecting to find a freaky toad, but that's exactly what happened. The amphibian kept colliding with their feet and anything else around it.
This toad appeared to be blind. It was missing its entire face. Initially, it seemed like something out of a strange tale, but the adult American toad was otherwise healthy, and the gap where its face should have been was covered with old scar tissue.
How did it survive?
Sadly, researchers suspect the toad didn't last long after its discovery. It was likely hibernating when it was attacked, with its nose, eyes, jaw, and tongue removed. For some unknown reason, the predator left the toad alive, despite its brutal injuries.
Left in peace and without the need to hunt for food, the remaining hibernation period gave the toad time to heal. However, when it woke up, it was blind and unable to forage. Even though it avoided predators, the toad's fate was sealed—starvation was inevitable.
2. They Inspired Frankenstein
In the 18th century, an Italian doctor named Luigi Galvani shocked frog legs with electricity. When they twitched, it sparked excitement. Electricity was a newly discovered force, still shrouded in mystery. As the experiments seemed to bring life back, it inspired the practice of galvanism—the pursuit of reanimating the dead through electricity.
This was one of the ideas that inspired Mary Shelley's 1818 gothic novel, Frankenstein. Another well-known figure of the time, Lord Byron, was a close friend of Shelley. She once confided in him, saying, 'Perhaps a corpse could be reanimated; galvanism had given proof of such possibilities: perhaps the parts of a creature might be assembled, given life, and infused with warmth.'
This concept became the foundation for Shelley's protagonist, Dr. Frankenstein. While galvanism is now outdated, it played a pivotal role in bringing a classic story to life. All of this thanks to the twitching frog legs.
1. Eyes Inside Frog’s Mouth
One day, two Canadian girls stumbled upon a toad that appeared to be missing its eyes. However, a local journalist pointed out that the toad seemed much more aware of its surroundings when its mouth opened. This observation led to a curious mystery: the creature had eyes, but they were oddly positioned on the roof of its mouth.
This was likely a case of macromutation—a drastic alteration at birth, rather than a gradual evolutionary change over generations. While small genetic shifts typically cause such phenomena, this particular toad's condition had never been observed before.
One possible cause of macromutation is parasitic infection. Specifically, the trematode worm can cause amphibians to develop extra, malformed, or missing back legs. However, this was not the case here. The toad's eyeballs were fully functional, just in the wrong place—far from the limb deformities caused by the worm.
