I often define myself as a scientist by kinds of questions I ask, so I normally say that I am an integrative evolutionary biologist or physiologist. But another way that you can characterize a scientist is by the type of organisms that they study, and by that criterion, I am definitely a herpetologist. The overwhelming majority of my publications (>95%) are on reptiles or amphibians, and most grad and undergrad students in my lab have studied reptiles and amphibians. So why do I study reptiles and amphibians?
Unlike other vertebrate groups, studying reptiles and amphibians requires a bit of justification. If you study birds, mammals, or “fishes”, usually there is the potential for something that can be applied to humans or one of our food sources, either in the context of agriculture or wildlife and fisheries biology. Reptiles and amphibians are only rarely an important food source, and none have really been domesticated and cultured in captivity like some birds, mammals, and fishes. Hence, the justification for studying reptiles and amphibians usually requires justifying on the basis of basic scientific knowledge that can be gained by studying them. I think that there are at least five reasons for why reptiles and amphibians can make good study systems in organismal biology.
One of the reasons that reptiles and amphibians are a good model system is that you can handle most of them safely. Amphibians and reptiles have very few zoonoses, and washing your hands after handling them is usually sufficient to protect against getting sick. As long as you are gentle, most reptiles and amphibians can also be handled without danger to the animal itself (although this can be complicated with some amphibians, and best practices is to have wet hands and/or a barrier like gloves). Most non-venomous squamates (snakes and lizards) can’t really hurt you if they bite you besides drawing a little blood, with the obvious exceptions of the big ones (e.g., pythons, iguanas, monitor lizards). Almost all turtles are capable of delivering a painful bite, and the big ones can do some real damage (such as removing digits), but they are not that flexible and so can generally be handled safely by holding onto the rear margin of the carapace (upper shell) between the two hind legs. Crocodilians are an exception- there is no way to safely handle any species without substantial training. Where I grew up in the Midwest, there were no venomous snakes, and so I grew up catching toads and turtles and snakes. The reason that at child could catch these animals (and grow fascinated with them) is also what makes them great study systems- they can be easy to catch safely, sometimes in large numbers.
Another reason for the appeal of reptiles and amphibians as study systems is that they are a vertebrate that can be extremely abundant. Because they are ectothermic and are often small bodied, they can be packed more densely into a landscape than even comparably sized birds or mammals, which must divert most of their energy input into endothermy. In the eastern US, red-backed salamanders (Plethodon cinereus) can be at extremely high densities- I have found over fifty individuals in a half hour of searching, and this was a random site that I was visiting for the first time. In the Midwest, snakes can be present in extremely high numbers- a single afternoon can yield dozens of garter snakes in wet prairies in Iowa or hundreds of ringnecked snakes in Kansas. Anyone who has spent time in the desert southwest has surely noted the abundance of many different species of lizards even in a resource-depauperate aridland. Scientists, particularly those that work in nature with wildlife, are often in a struggle to increase sample size and statistical robustness of results, and reptiles and amphibians are often the best way to get a high sample size for a terrestrial vertebrate.
Beyond permitting high sample size, the fact that all reptiles and amphibians (with a few facultative exceptions) are ectotherms means that they represent a very unique style of terrestrial life, compared to birds and mammals. All mammals and birds are limited in the body size and shape that they can evolve based upon the constraint of being endothermic. Surface area to volume relationships means that there is a limit on how small you can be and maintain a body temperature higher than that of the environment. These same constraints also prevent the evolution of body forms with a high surface area to volume ratio, such as very elongate or flattened forms. Hence, within reptiles and amphibians, we have snakes and caecilians and legless lizards, as well as flattened horned toad and softshell turtles. The smallest terrestrial vertebrates are reptiles and amphibians of multiple different lineages. Hence, if you want to understand nearly half of the diversity of tetrapods (tetrapods are basically all terrestrial vertebrates, or all vertebrates excluding “fishes”), studying reptiles and amphibians is the only way to do it.
Reptiles and amphibians are also good study systems because they are very sensitive to the environment, and can be bellwethers of environmental disturbance. All reptiles and amphibians are ectotherms, so they are often sensitive to or responsive to environmental shifts in temperature. Many species are habitat specialists, and cannot persist outside of their specialized habitats. Reptiles and amphibians are sensitive to wildlife disease, from two different chytrid diseases that have caused enormous crashes in the biodiversity of salamanders and anurans, to snake fungal disease that is negatively impacting populations of snakes in the US, particularly the eastern US. Moreover, because many are small-bodied and feed upon tiny invertebrates, they can connect parts of the food web that would be otherwise separated. In fact, loss of amphibian communities has been linked to the collapse of other vertebrate taxa, emphasizing their important but environmentally sensitive role in the ecosystem.
Finally, studying reptiles and amphibians is useful and interesting because we know so little about them. New species of squamates and amphibians are described at a pace that far outstrips descriptions of new mammals and birds. Some groups like amphisbaenians, scolecophidian snakes, and caecilians, among others, are still quite poorly known, with new families of caecilians discovered in the past couple of decades. One reason that we are discovering many new species is that many are quite cryptic and live in places where they are unlikely to encounter humans, such as the canopy of trees or underground. Because of that, we are also constantly learning new information on the ecology and behavior of reptiles and amphibians. As an example, only a few years ago, researchers discovered that not only do caecilians have post-birth parental care, but the offspring beg to be fed, and the mothers release cloacal milk in response to the begging of their offspring. This observation challenges our notions of when and where elaborate parental care evolved on the tree of life.
There are many other reasons to study reptiles and amphibians (e.g,, public health issues around venomous snakes, studying the evolution of toxins and venom). But I wanted to at least give a sampling of why it might be not only interesting, but important, to study these creatures. Reptiles and amphibians are fascinating and cool, and for all of the reasons that they are so appealing to some people, they can make great study systems in integrative and comparative biology.
Unlike other vertebrate groups, studying reptiles and amphibians requires a bit of justification. If you study birds, mammals, or “fishes”, usually there is the potential for something that can be applied to humans or one of our food sources, either in the context of agriculture or wildlife and fisheries biology. Reptiles and amphibians are only rarely an important food source, and none have really been domesticated and cultured in captivity like some birds, mammals, and fishes. Hence, the justification for studying reptiles and amphibians usually requires justifying on the basis of basic scientific knowledge that can be gained by studying them. I think that there are at least five reasons for why reptiles and amphibians can make good study systems in organismal biology.
One of the reasons that reptiles and amphibians are a good model system is that you can handle most of them safely. Amphibians and reptiles have very few zoonoses, and washing your hands after handling them is usually sufficient to protect against getting sick. As long as you are gentle, most reptiles and amphibians can also be handled without danger to the animal itself (although this can be complicated with some amphibians, and best practices is to have wet hands and/or a barrier like gloves). Most non-venomous squamates (snakes and lizards) can’t really hurt you if they bite you besides drawing a little blood, with the obvious exceptions of the big ones (e.g., pythons, iguanas, monitor lizards). Almost all turtles are capable of delivering a painful bite, and the big ones can do some real damage (such as removing digits), but they are not that flexible and so can generally be handled safely by holding onto the rear margin of the carapace (upper shell) between the two hind legs. Crocodilians are an exception- there is no way to safely handle any species without substantial training. Where I grew up in the Midwest, there were no venomous snakes, and so I grew up catching toads and turtles and snakes. The reason that at child could catch these animals (and grow fascinated with them) is also what makes them great study systems- they can be easy to catch safely, sometimes in large numbers.
Another reason for the appeal of reptiles and amphibians as study systems is that they are a vertebrate that can be extremely abundant. Because they are ectothermic and are often small bodied, they can be packed more densely into a landscape than even comparably sized birds or mammals, which must divert most of their energy input into endothermy. In the eastern US, red-backed salamanders (Plethodon cinereus) can be at extremely high densities- I have found over fifty individuals in a half hour of searching, and this was a random site that I was visiting for the first time. In the Midwest, snakes can be present in extremely high numbers- a single afternoon can yield dozens of garter snakes in wet prairies in Iowa or hundreds of ringnecked snakes in Kansas. Anyone who has spent time in the desert southwest has surely noted the abundance of many different species of lizards even in a resource-depauperate aridland. Scientists, particularly those that work in nature with wildlife, are often in a struggle to increase sample size and statistical robustness of results, and reptiles and amphibians are often the best way to get a high sample size for a terrestrial vertebrate.
Beyond permitting high sample size, the fact that all reptiles and amphibians (with a few facultative exceptions) are ectotherms means that they represent a very unique style of terrestrial life, compared to birds and mammals. All mammals and birds are limited in the body size and shape that they can evolve based upon the constraint of being endothermic. Surface area to volume relationships means that there is a limit on how small you can be and maintain a body temperature higher than that of the environment. These same constraints also prevent the evolution of body forms with a high surface area to volume ratio, such as very elongate or flattened forms. Hence, within reptiles and amphibians, we have snakes and caecilians and legless lizards, as well as flattened horned toad and softshell turtles. The smallest terrestrial vertebrates are reptiles and amphibians of multiple different lineages. Hence, if you want to understand nearly half of the diversity of tetrapods (tetrapods are basically all terrestrial vertebrates, or all vertebrates excluding “fishes”), studying reptiles and amphibians is the only way to do it.
Reptiles and amphibians are also good study systems because they are very sensitive to the environment, and can be bellwethers of environmental disturbance. All reptiles and amphibians are ectotherms, so they are often sensitive to or responsive to environmental shifts in temperature. Many species are habitat specialists, and cannot persist outside of their specialized habitats. Reptiles and amphibians are sensitive to wildlife disease, from two different chytrid diseases that have caused enormous crashes in the biodiversity of salamanders and anurans, to snake fungal disease that is negatively impacting populations of snakes in the US, particularly the eastern US. Moreover, because many are small-bodied and feed upon tiny invertebrates, they can connect parts of the food web that would be otherwise separated. In fact, loss of amphibian communities has been linked to the collapse of other vertebrate taxa, emphasizing their important but environmentally sensitive role in the ecosystem.
Finally, studying reptiles and amphibians is useful and interesting because we know so little about them. New species of squamates and amphibians are described at a pace that far outstrips descriptions of new mammals and birds. Some groups like amphisbaenians, scolecophidian snakes, and caecilians, among others, are still quite poorly known, with new families of caecilians discovered in the past couple of decades. One reason that we are discovering many new species is that many are quite cryptic and live in places where they are unlikely to encounter humans, such as the canopy of trees or underground. Because of that, we are also constantly learning new information on the ecology and behavior of reptiles and amphibians. As an example, only a few years ago, researchers discovered that not only do caecilians have post-birth parental care, but the offspring beg to be fed, and the mothers release cloacal milk in response to the begging of their offspring. This observation challenges our notions of when and where elaborate parental care evolved on the tree of life.
There are many other reasons to study reptiles and amphibians (e.g,, public health issues around venomous snakes, studying the evolution of toxins and venom). But I wanted to at least give a sampling of why it might be not only interesting, but important, to study these creatures. Reptiles and amphibians are fascinating and cool, and for all of the reasons that they are so appealing to some people, they can make great study systems in integrative and comparative biology.
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