Tag Archives: #frogs

This Frog Has Lungs That Act Like Noise-canceling Headphones (Biology)

To succeed in mating, many male frogs sit in one place and call to their potential mates. But this raises an important question familiar to anyone trying to listen to someone talking at a busy cocktail party: how does a female hear and then find a choice male of her own species among all the irrelevant background noise, including the sound of other frog species? Now, researchers reporting March 4 in the journal Current Biology have found that they do it thanks to a set of lungs that, when inflated, reduce their eardrum’s sensitivity to environmental noise in a specific frequency range, making it easier to zero in on the calls of their mates.

“In essence, the lungs cancel the eardrum’s response to noise, particularly some of the noise encountered in a cacophonous breeding ‘chorus,’ where the males of multiple other species also call simultaneously,” says lead author Norman Lee of St. Olaf College in Minnesota.

The researchers explain that what their lungs are doing is called “spectral contrast enhancement.” That’s because it makes the frequencies in the spectrum of a male’s call stand out relative to noise at adjacent frequencies.

“This is analogous to signal-processing algorithms for spectral contrast enhancement implemented in some hearing aids and cochlear implants,” says senior author Mark Bee of the University of Minnesota-Twin Cities. “In humans, these algorithms are designed to amplify or ‘boost’ the frequencies present in speech sounds, attenuate or ‘filter out’ frequencies present between those in speech sounds, or both. In frogs, the lungs appear to attenuate frequencies occurring between those present in male mating calls. We believe the physical mechanism by which this occurs is similar in principle to how noise-canceling headphones work.”

It’s long been known to scientists that vocal signals are key to reproduction in most frogs. In fact, frogs possess a unique sound pathway that can transmit sounds from their air-filled lungs to their air-filled middle ears through the glottis, mouth cavity, and Eustachian tubes. But the precise function of this lung-to-ear sound transmission pathway had been a puzzle. Earlier studies suggested that the frog’s lungs might play a role in increasing the degree to which eardrum vibrations were direction dependent, thereby improving the ability of listeners to locate a sexually advertising male. But Bee’s team has found that wasn’t the case.

Further analysis of the data suggested a different explanation: while the state of the lungs’ inflation had no effect on directional hearing, there was a substantial impact on the sensitivity of the eardrum. With inflated lungs, the eardrum vibrated less in response to sounds in a specific frequency range. It led them to a new idea: that the lungs were dampening vibrations, thereby canceling out noise.

This image shows a pair of Green treefrogs mating © Norman Lee

Indeed, their studies using laser vibrometry showed that the resonance of inflated lungs selectively reduces the eardrum’s sensitivity to frequencies between the two spectral peaks present in the mating calls of frogs of the same species. It confirmed that a female can hear males of her own species no matter the state of her lungs’ inflation. So, the lungs had no impact on the “signals” of interest to a female. But what about the “noise”?

They already knew that a major source of noise for any given species of frog is the calls of other frog species breeding at the same time and calling in the same choruses. But they had no idea how many or which other species might “co-call” in a mixed species chorus with green treefrogs across its geographic range, much less how the frequency spectrum of their calls looked. To find out, they turned to publicly available data from a citizen science project called the North American Amphibian Monitoring Program. Their analysis of those data suggests that the green treefrog’s inflated lungs would make it harder to hear the calls of other species while leaving their ability to hear the calls of their own species intact.

“Needless to say, we think this result–a frog’s lungs canceling the eardrum’s response to noise created by other species of frogs–is pretty cool!” Bee says.

Finally, they created a physiological model of sound processing by the green treefrog’s inner ear to examine how the lung’s impact on the eardrum might be converted into more robust neural responses to the calls of their own species. They think it works like this: the inner ear is, in some ways, “tuned” to respond best to the frequencies in the species’ own calls. But that tuning is not perfect. The authors suggest that a primary function of the lungs in hearing is to sharpen or improve this tuning, allowing the inner ear to generate relatively stronger neural responses to the species’ own calls by reducing the neural responses driven by the calls of other species.

The findings demonstrate the power of evolution to co-opt pre-existing adaptations for new functions, the researchers say. In future work, they want to find out more about the physical interaction between the three sources of sound (external, internal via the opposite ear, and internal via the lungs) that determine the eardrum’s vibration response. They also want to know more about how widespread noise cancellation is in frogs.

This work was supported by the U.S. National Science Foundation.

Featured image: This image shows a male Green treefrog calling © Norman Lee


Reference: Lee et al.: “Lung Mediated Auditory Contrast Enhancement Improves the Signal-to-Noise Ratio for Communication in Frogs”, Current Biology, 2021.
https://www.cell.com/current-biology/fulltext/S0960-9822(21)00113-5


Provided by Cell Press

A Deadly Fungus is Killing Frogs Around the World, But the Bacteria On Their Skin Could Protect Them (Biology)

Researchers in Costa Rica have found that some bacteria on the skin of amphibians prevent growth of the fungus responsible for what has been dubbed ‘the amphibian apocalypse’.

Published in the journal Microbiologythe research identified a number of bacteria which could growth of the fungus Batrachochytrium dendrobatidis (Bd). One particularly dangerous strain of the fungus,called BdGPL-2, is responsible for mass amphibian die-offs around the world.

The fungus infects the skin of amphibians, breaking down the cells. As amphibians breathe and regulate water through their skin, infection is often deadly. It is believed that almost 700 species of amphibian are vulnerable to the fungus, and Bd has led to the extinction of 90 amphibian species.

In order to investigate why some amphibian populations in Costa Rica were more resilient to Bd that others, a research group led by Dr Adrian Pinto, Professor at the University of Costa Rica sampled the circulating strains of Bd and the skin microbiome of amphibians at different sites.

To do this, the research group collected wild amphibians from areas of Costa Rica which had a history of Bd outbreaks. “Bd has previously been widely detected in Costa Rica, but this is the first study to isolate and compare the characteristics of different isolates,” said Dr Pinto, “our work showed that the circulating strains of the pathogenic fungus belong to a highly virulent global strain known as BdGPL-2.”

They found that the bacteria on the skin of some surviving amphibians prevented growth of the fungus in the lab. “Amphibian species that survived decline harbor bacteria on their skin capable of inhibiting the growth of the pathogen. However, this inhibitory capacity varies according to which strain of the fungus is being tested,” said Dr Pinto. “These findings suggest that locally adapted skin bacteria may offer protection from the disease.”

Although the researchers expected to see the highly virulent strain BdGPL-2 in Costa Rica, they did not expect to see so much variation in circulating strains. “We were surprised of the phenotypic variations among the pathogen isolates, including their different responses to the antagonistic bacteria,” said Dr Pinto. “Local pathogen adaptations must be considered when designing mitigation strategies for this disease.”

Dr Pinto hopes to combine their findings with other disease control strategies to protect amphibian populations from decimation by Bd: “We will further study the ability of skin bacteria to protect amphibians against disease, as another tool to combat this plague alongside the creation of climate shelters and fostering the amphibians’ own immune system,” he said.

Costa Rica is one of the countries that suffered a dramatic loss of amphibian species between the 1980 and 1990. In Costa Rica, there are currently 64 species of amphibians in some risk category according to the International Union for the Conservation of Nature. Species classified as critically endangered include the Holdridge’s Toad (Incilius holdridgei), a native species found only in the mountain ranges of the central region; The Variable Harlequin Frog (Atelopus varius), a river species very sensitive to Bd, and several species of river tree frogs of the genus Isthmohyla that live in cold currents in high areas, a habitat where Bd proliferates successfully.

Amphibians are one of the most diverse groups in the tropics and represent crucial links in food webs. Protecting them keeps ecosystems healthy since biological diversity is the basis for resilient forests, thus helping control pests and zoonotic infections.


Reference: Juan G. Abarca, Steven M. Whitfield et al., “Genotyping and differential bacterial inhibition of Batrachochytrium dendrobatidis in threatened amphibians in Costa Rica”, Microbiology Society, 2021. https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.001017


Provided by Microbiology Society

Glass Frogs Living Near Roaring Waterfalls Wave Hello to Attract Mates (Biology)

Most frogs emit a characteristic croak to attract the attention of a potential mate. But a few frog species that call near loud streams — where the noise may obscure those crucial love songs — add to their calls by visually showing off with the flap of a hand, a wave of a foot or a bob of the head. Frogs who “dance” near rushing streams have been documented in the rainforests of India, Borneo, Brazil and, now, Ecuador.

A UC Berkeley conservation ecologist has discovered that an elusive glass frog species (Sachatamia orejuela) uses both high-pitched calls and visual signaling — in the form of hand-waving, foot-waving and head-bobbing — to communicate near loud waterfalls. (Photo courtesy Rebecca Brunner)

Conservation ecologist Rebecca Brunner, a Ph.D. candidate at the University of California, Berkeley, has discovered that the glass frog Sachatamia orejuela can be added to the list of species that make use of visual cues in response to their acoustic environments. This is the first time a member of the glass frog family (Centrolenidae) has been observed using visual communication in this manner.

“A handful of other frog species around the world use visual signaling, in addition to high-pitched calls, to communicate in really loud environments,” Brunner said. “What’s interesting is that these species are not closely related to each other, which means that these behaviors likely evolved independently, but in response to similar environments — a concept called convergent evolution.”

Video: Brunner captured video of the Sachatamia orejuela glass frog “waving” its arm, likely in an effort to attract a mate. This is the first time a member of the glass frog family has been observed using visual signalling. (UC Berkeley video)

Sachatamia orejuela glass frogs are native to the rainforests of Ecuador and Colombia. They are especially unique because they are almost exclusively found on rocks and boulders within the spray zones of waterfalls, where rushing water and slippery surfaces offer some protection against predators, and their green-gray color and semi-transparent skin make them nearly impossible to spot. As a result, little is known about this species’ mating and breeding behavior.

Brunner’s colleague captured a photo of her climbing a slippery rock face to film the glass frog. (Photo courtesy Rebecca Brunner)

Brunner, who studies the bioacoustics of different ecological environments, was chest-deep in an Ecuadorean rainforest stream recording the call of a Sachatamia orejuela when she first observed this visual signaling behavior. As soon as she saw the frog repeatedly raising its front and back legs, Brunner climbed a slippery rock face and balanced on one foot to get video footage of the behavior.

“I was already over the moon because I had finally found a calling male after months of searching. Before our publication, there was no official record of this species’ call, and basic information like that is really important for conservation,” Brunner said. “But then I saw it start doing these little waves, and I knew that I was observing something even more special.”

While she filmed, the frog continued to wave its hands and feet and bob its head. She also observed another male Sachatamia orejuela glassfrog a few meters away performing the same actions.

Glass frogs are named for their semi-transparent skin. (Photo courtesy Rebecca Brunner)

This is a really exhilarating discovery because it’s a perfect example of how an environment’s soundscape can influence the species that live there. We’ve found that Sachatamia orejuela has an extremely high-pitched call, which helps it communicate above the lower-pitched white noise of waterfalls. And then to discover that it also waves its hands and feet to increase its chances of being noticed —  that’s a behavior I’ve always loved reading about in textbooks, so it is beyond thrilling to be able to share another amazing example with the world,” said Brunner.

Though the COVID-19 pandemic has put a pause on Brunner’s fieldwork, she hopes to return to Ecuador soon to continue her research, which links bioacoustics and conservation.

“One of the best things about fieldwork is that nature is always full of surprises — you never know what discoveries you may happen upon,” Brunner said. “I hope our findings can serve as a reminder that we share this planet with incredible biodiversity. Conserving ecosystems that support species like Sachatamia orejuela is important not only for our well-being, but also for our sense of wonder.”

Juan M. Guayasamin, professor of biology at Universidad San Francisco de Quito, is a co-author of this research, which appears in the journal Behaviour. Brunner’s fieldwork was supported by a National Geographic Explorer Grant (EC-57058R-19) and a National Science Foundation Graduate Research Fellowship.

Reference: Rebecca M. Brunner and Juan M. Guayasamin, “Nocturnal visual displays and call description of the cascade specialist glassfrog Sachatamia orejuela”, Behavior, Volume 157: Issue 14-15, pp. 1257–1268, https://brill.com/view/journals/beh/157/14-15/article-p1257_9.xml https://doi.org/10.1163/1568539X-bja10048

Provided by University of California Berkeley

How Do Some Frogs ‘Rebound’ After Disease While Others Perish? (Biology)

A new study shows how some species survive infectious disease epidemics, and how we can use this knowledge to assist and direct wildlife management.

Wildlife diseases are a major cause of wildlife decline around the world.

But despite their devastating effects, some wildlife species survive these disease epidemics and some populations even rebound, increasing their numbers.

Queensland’s Common Mistfrog populations have declined due to chytridiomycosis. Picture: Lee Skerratt/University of Melbourne.

Amphibians are some of the most threatened animals in the world, with over 30 per cent listed as vulnerable or endangered species on the International Union for Conservation of Nature (IUCN) list. And disease is a major cause of these declines.

But why do some species survive and others don’t?

To help answer this, Dr. Laura A Brannelly and her team decided to go through all of the relevant research literature to understand what makes a species thrive in natural conditions to improve species management outcomes, but also help avoid management mistakes.

They used amphibian declines as a case study for how best to understand the ways that species survive declines.

It turns out that for most species, they actually do not yet understand why they are persisting after disease caused declines.

This is partly because, as they show in their analysis, there is wide variation across species and life stages, which highlights the importance of community, where different species of frogs change disease impacts.

Even for species that have been heavily studied by different research teams, like the endangered common mist frog, Litoria rheocola, from the Australian tropics, they do not understand why some populations are surviving.

The fungal pathogen Batrachochytrium dendrobatidis causes the disease chytridiomycosis, which affects amphibian skin function. Picture: Shutterstock.

To help researchers better comprehend how species survive, they identified key criteria to guide future research that will help us understand the ways that populations rebound in the future.

They also show why we should use this information to improve management practices.

Frogs are declining globally due to the fungal pathogen Batrachochytrium dendrobatidis, known as Bd. The Bd fungus causes the disease chytridiomycosis, which affects amphibian skin function.

Amphibian skin is especially important for frogs because they use it to breath, absorb water and even maintain ions in their blood. This disease causes thickening of their skin, and disrupts the normal skin function in infected frogs, ultimately causing death due to cardiac arrest.

Chytridiomycosis occurs globally and has resulted in declines in over 500 species around the world in the last 50 years and has even caused 90 species extinctions including some species in Australia like the gastric brooding frog.

Many other species remain on the verge of extinction like the southern corroboree frog, which requires management to remain in the wild, including breeding programs, reintroductions and habitat management.

Despite these massive declines, there are some species who declined but then survived and remained, like the alpine tree frog, Litoria verreauxii alpina.

This species used to be widespread in the Australian Alps, but now remains at a handful of locations, although has remained stable at those locations for a couple of decades following the initial epidemic.

Even in some areas of pristine habitat, the alpine tree frog has gone extinct. Picture: Supplied.

In their latest study published in Ecology Letters, they highlight the conditions and traits that allow frogs to persist after an epidemic.

They found that frogs, like the alpine tree frog, can persist after their population has declined due to changes in the frog, such as through reproduction where infected animals actually increase their breeding behaviour or produce more offspring when infected.

Other frogs persist through increased resistance or tolerance to disease by evolving increased immunity or behaviour, such as avoiding disease or through regulating its body temperature by moving to warmer habitats or parts of habitats to help fight infection, a term called behavioural fever in ectotherms, commonly known as “cold-blooded” animals.

The habitat of the animals can also influence decline patterns because Bd thrives better in cooler, wetter habitats.

Frogs might also persist if virulence of the pathogen reduces over time which has not been observed but is possible.

And finally, an often overlooked way that animals can persist is through understanding how the disease is transmitted, and how the ecological community affects disease.

The alpine tree frogs are surviving because they are prioritising breeding and reproduction over increased immunity to the chytrid fungus. Picture: Laura Brannelly.

The ecological community includes the animals, plants and all other organisms in the frogs environment, and can include reservoir hosts that maintain disease in the system.

Reservoir hosts for the pathogen can be other species of frogs, but also include other organisms like crayfish that live with frogs. Reservoir hosts have a high tolerance to infection, meaning that they can carry high loads and not be impacted by the disease themselves.

In Australia a possible reservoir host is the southern brown frog, Litoria ewingii. And if a susceptible or threatened species, like the green and golden bell frog, Litoria aurea, live at sites with these reservoir hosts, then they might be more likely to decline.

Understanding the ways that species are persisting is important for management, because management actions will be more effective if we support how the animals are persisting naturally.

For example, the alpine tree frogs are surviving because they are prioritising breeding and reproduction over increased immunity. Since the arrival of chytridiomycosis, they are ensuring that they breed before succumbing to disease in a pond with permanent water, allowing the population to persist.

This means that management action should be focussed on supporting successful breeding and tadpole development and access to permanent water reserves.

If threatened species like the green and golden bell frog live at sites with fungus reservoir hosts, they might be more likely to decline. Picture: WikiCommons/Bernard Spragg

Through their research, they highlight that even with multiple decades of well-intentioned research devoted to understanding the impacts of chytridiomycosis on frogs, they know very little about how most species actually are persisting.

Without information to understand the ways that species persist after disease related declines, deciding on management actions is complicated. And even more importantly, it could lead to failure and exacerbate declines.

For example, for a species that is persisting at a low frog density which reduces transmission of Bd, adding captive-reared individuals to populations might increase the frog density and therefore increase transmission and disease within the population.

Without understanding how a species is persisting naturally, we could completely mismanage these threatened animals, and possibly lead to further declines.

They highlight that both researchers and managers need to work together, and research should be aimed at understanding the mechanisms of population persistence.

By using this knowledge we can plan management actions to support the ecology and biology of the species we are trying to save.

This work is a multi-institutional collaboration across the University of Melbourne, Griffith University, Southern Cross University, and international collaborations in the US and Spain.

Provided by University Of Melbourne

Primates Aren’t Quite Frogs (Neuroscience)

Spinal modules in macaques can independently control forelimb force direction and magnitude.

Researchers in Japan demonstrated for the first time the ‘spinal motor module hypothesis’ in the primate arm, opening a new pathway for recovery after disease or injury.

An experiment nearly 40 years ago in frogs showed that their leg muscles were controlled by simultaneously recruitment of two modules of neurons. It’s a bit more complex in macaques (The National Center of Neurology and Psychiatry).

The human hand has 27 muscles and 18 joints, which our nervous system is able to coordinate for complex movements. However, the number of combinations — or degrees of freedom — is so large that attempting to artificially replicate this control and adjustment of muscle activity in real time taxes even a modern supercomputer. While the method used by the central nervous system to reduce this complexity is still being intensely studied, the “motor module” hypothesis is one possibility.

Under the motor module hypothesis, the brain recruits interneuronal modules in the spinal cord rather than individual muscles to create movement; wherein different modules can be combined to create specific movements. Nearly 40 years ago, research in frogs showed that simultaneously recruiting two modules of neurons controlling leg muscles created the same pattern of motor activity that represents a “linear summation” of the two component patterns.

An international team of researchers, led by Kazuhiko Seki at the National Center of Neurology and Psychiatry’s Department of Neurophysiology, in collaboration with David Kowalski of Drexel University and Tomohiko Takei of Kyoto University’s Hakubi Center for Advanced Research, attempted to determine if this motor control method is also present in the primate spinal cord. If validated, it would provide new insight into the importance of spinal interneurons in motor activity and lead to new ideas in movement disorder treatments and perhaps even a method to “reanimate” a limb post-spinal injury.

The team implanted a small array of electrodes into the cervical spinal cord in three macaques. Under anesthesia, different groups of interneurons were recruited individually using a technique called intraspinal microstimulation, or ISMS. The team found that, as in the frog leg, the force direction of the arm at the wrist during dual-site simulation was equal to the linear summation of the individually recruited outputs. However, unlike the frog leg, the force magnitude output could be many times higher than that expected from a simple linear summation of the individual outputs. When the team examined the muscle activity, they found that this supralinear summation was in a majority of the muscles, particularly in the elbow, wrist, and finger.

“This is a very interesting finding for two reasons,” explains Seki. “First, it demonstrates a particular trait of the primate spinal cord related to the increased variety of finger movements. Second, we now have direct evidence primates can use motor modules in the spinal cord to control arm movement direction and force magnitude both efficiently and independently.”

In effect, using paired stimulation in the primate spinal cord not only directly activate two groups of interneurons, INa and INb, which recruit their target muscle synergies, Syn-a and Syn-b, to set the arm trajectory, but can also activate a third set of interneurnons that can adapt the motor activity at the spinal level to change the force of the movement, group INc. This would let the brain plan the path the arm should take while the spinal cord adapts the muscle activity to make sure that path happens.

One example of this “plan and adapt” approach to motor control is the deceptively simple act of drinking from a can of soda. The brain can predetermine the best way to lift the can to your mouth for a sip, but the actual amount of soda in the can — and therefore the can’s weight — is perhaps unknown. Once your brain has determined the trajectory the can should take — in this case INa and INb — the amount of force needed to complete that action can be modulated separately in INc, rather than redetermining which sets of muscles will be needed.

This study experimentally proves for the first time that primate arm movements may be efficiently controlled by motor modules present in the spinal cord. Based on the results of this research, it is expected that the analysis and interpretation of human limb movements based on the motor module hypothesis will further advance in the future.

In the field of robotics, this control theory may lead to more efficient methods to create complex limb movements, while in the field of clinical medicine, it is expected that new diagnostic and therapeutic methods will be created by analyzing movement disorders caused by neurodegenerative diseases and strokes.

References: Amit Yaron, David Kowalski, Hiroaki Yaguchi, Tomohiko Takei, and Kazuhiko Seki, “Forelimb force direction and magnitude independently controlled by spinal modules in the macaque”, Proceedings of the National Academy of Sciences of the United States of America, 2020. DOI】https://doi.org/10.1073/pnas.1919253117

Provided by Kyoto University

The Secret of How Frogs See the World (Biology)

It’s clear to see that species like tree frogs have gigantic eyes, but the visual systems of most frogs have gone largely unstudied by scientists.

Leptopelis brevirostris, Bioko Island, Equatorial Guinea.Source: Christian Irian. See ‘Eye size and investment in frogs and toads correlate with adult habitat, activity pattern and breeding ecology’ by Thomas et al., published in Proc. R. Soc. B.

An international, interdisciplinary team of researchers is starting to change that. In the first study to come out of the collaboration, the team examined museum specimens representing all 55 frog families to test hypotheses about the evolution of frog eye size and its relationship to different aspects of their lifestyles. The results show that, overall, frogs are investing a lot of energy in maintaining their eyes and that vision is likely important to their survival and reproductive success.

Rayna Bell, assistant curator of herpetology at the California Academy of Sciences and one of the new paper’s authors, says that although frogs were an early model for studying vision at the turn of the 20th century, the research was limited to a small number of easily accessible species.

“It was not reflective of the enormous diversity of frogs that we know exist today,” she says. “Our understanding of vision in frogs has lagged behind such research in other vertebrates, such as fishes, birds, and mammals.”

There are more than 7,000 frog species living in a variety of different habitats and ecosystems: Some spend their entire lives underwater, others live in the treetops, and others burrow underground.

Ceratophrys cornuta, the Amazonian Horned Frog from Kaw, French Guiana.Source: Christian L. Cox. See ‘Eye size and investment in frogs and toads correlate with adult habitat, activity pattern and breeding ecology’ by Thomas et al., published in Proc. R. Soc. B.

The first goal of Bell and her colleagues was to broaden out from those initial frog species whose vision had been characterized historically and document the diversity in eye size among frogs. To do this, her team depended primarily on specimens preserved in natural history collections around the world. They measured eye size in 220 frog species representing all 55 families.

The study revealed that frogs have relatively large eyes for their body size, with certain species of tree frog coming out on top. Bell says that relative eye size is an indication of how much of an organism’s energy budget is invested in eye tissue.

“Eyes are metabolically expensive to maintain, so if you have large eyes, that suggests you are relying pretty heavily on vision and investing energy in maintaining that eye tissue,” she says.

Incilus alvarius, the Sonoran Desert Toad from Sonora, Mexico.Source: Jeffrey W. Streicher. See ‘Eye size and investment in frogs and toads correlate with adult habitat, activity pattern and breeding ecology’ by Thomas et al., published in Proc. R. Soc. B.

The team also tested whether eye sizes were correlated with life history traits like where the frogs lived or whether they are active at day or night. As is seen in other animals, there was a strong association between habitat type and eye size, with species that live underground or in murky water having reduced eyes. It’s likely that in these light-deficient environments, animals are not relying as much on vision and it’s not worth it to invest in growing large eyes.

Bell says this study is an important first step in understanding the diversity of eye size in frogs. Next, she and her colleagues are looking at the genetic underpinnings of this variation and characterizing photoreceptor sensitivity in different frogs. She’s also interested in how frogs’ visual systems change as they develop from aquatic tadpoles into adults who might live in a very different habitat.

“It’s interesting from an evolutionary perspective but also from a behavioral perspective, in terms of understanding how frogs are sensing and interacting with their environment,” says Bell.

“We know that they have big eyes. We don’t know specifically why but we’re working on it.”

References: Thomas KN, Gower DJ, Bell RC, Fujita MK, Schott RK, and Streicher JW. (2020). Eye size and investment in frogs and toads correlate with adult habitat, activity pattern and breeding ecology. Proceedings of the Royal Society B 287: 20201393. Doi: 10.1098/rspb.2020.1393.

This article is republished here from psychology today under common creative licenses