Frogs debug themselves by absorbing tracking devices into their bladders
Christopher Tracy found the three radio transmitters lying on the forest floor. They were still intact and sending off a strong signal, but there was a big problem – all three of them were meant to be inside the body of a frog.
Several weeks before, Tracy had implanted transmitters into three species of Australian frogs to track their whereabouts. He had placed the devices into the frogs’ peritoneal cavity, a space within its belly that contains its stomach, guts and liver. But these ones were alone, with no bodies nearby or any signs of predators. The frogs hadn’t died or been eaten, but they had somehow removed the transmitters from an enclosed space within their bodies.
When Tracy located his other tagged frogs, he found an important clue: around three-quarters of the transmitters had moved to the animals’ bladders. Tracy was intrigued. He rounded up five more Australian tree frogs and five cane toads, implanted small beads into their bodies, and tracked them solidly for two to three weeks. After that time, he found that four of the toads had the beads in their bladders, and the other animals had urinated theirs out.
To track the beads’ expulsion more carefully, Tracy captured another 31 cane toads, stuck more beads into them and dissected them on successive days. He found that a thin flap of tissue slowly grew from the bladder and soon enveloped the beads, in as few as two days for some animals. Once surrounded, the beads were covered by another thicker layer, full of blood vessels. Soon, they were pulled into the bladder itself, floating freely until they happened to be peed out.
Many animals have managed to expel transmitters and other foreign objects from their bodies, including fish, snakes and crocodiles. Even in humans, surgical sponges left in the body have sometimes wormed their way into the intestines, only to be removed through the usual route. But all of these species purge their internal rubbish through the intestine or the skin – the bladder is a new route, although perhaps not an unexpected one.
Frogs famously jump a lot, and risk getting punctured by sharp nearby objects; the insects they swallow whole can also come in spiny shells. It makes sense for them to be able to get rid of any unwanted bodily junk. The bladder presents a good route – frog bladders are very large and they take up a lot of room. Any intruding objects are more likely to come into contact with the bladder than any other organ.
It’s a cute result, but one with potential importance for scientists who track amphibians – it could lead to people drawing false conclusions about the death or disappearance of frogs that had simply managed to debug their bodies.
Reference: Biology Letters http://dx.doi.org/doi:10.1098/rsbl.2010.0877
Photos by Michael Linnenbach and LiquidGhoul
More on frogs:
- First lungless frog discovered in Borneo
- ‘Wolverine’ frogs pop retractable claws from their toes
- Seven habits of highly successful toads
- Tree frogs shake their bums to send threatening vibes
- Pocket Science – belly-flopping frogs, and fattening marmots
- Coin-sized frog becomes mite-y thanks to poisonous diet
If the citation link isn’t working, read why here
Related Topics
Go Further
Animals
- These 'trash fish' are among Earth's most primitive animalsThese 'trash fish' are among Earth's most primitive animals
- These photos are works of art—and the artists are bugsThese photos are works of art—and the artists are bugs
- The epic migration of a 6-foot long, 200-pound catfishThe epic migration of a 6-foot long, 200-pound catfish
- Frans de Waal, biologist who studied animal emotion, dies at 75Frans de Waal, biologist who studied animal emotion, dies at 75
Environment
- Are synthetic diamonds really better for the planet? The answer isn't clear-cut.Are synthetic diamonds really better for the planet? The answer isn't clear-cut.
- This year's cherry blossom peak bloom was a warning signThis year's cherry blossom peak bloom was a warning sign
- The U.S. just announced an asbestos ban. What took so long?The U.S. just announced an asbestos ban. What took so long?
- The most dangerous job? Inside the world of underwater weldersThe most dangerous job? Inside the world of underwater welders
- The harrowing flight that wild whooping cranes make to surviveThe harrowing flight that wild whooping cranes make to survive
History & Culture
- Meet the powerful yokai that inspired the demon king in ‘Demon Slayer’Meet the powerful yokai that inspired the demon king in ‘Demon Slayer’
- A surprising must-wear for European monarchs? Weasels.A surprising must-wear for European monarchs? Weasels.
- Meet the woman who made Polaroid into a cultural iconMeet the woman who made Polaroid into a cultural icon
- Inside the observatory that birthed modern astrophysicsInside the observatory that birthed modern astrophysics
Science
- LED light treatments for skin are trendy—but do they actually work?LED light treatments for skin are trendy—but do they actually work?
- NASA smashed an asteroid. The debris could hit Mars.NASA smashed an asteroid. The debris could hit Mars.
- Humans really can have superpowers—scientists are studying themHumans really can have superpowers—scientists are studying them
- Why engineers are concerned about aging infrastructureWhy engineers are concerned about aging infrastructure
Travel
- 2024 will be huge for astrotourism—here’s how to plan your trip2024 will be huge for astrotourism—here’s how to plan your trip
- Play and stay in the mountains of eastern Nevada
- Paid Content
Play and stay in the mountains of eastern Nevada - This couple quit the city to grow wasabi in Japan's mountainsThis couple quit the city to grow wasabi in Japan's mountains