Davis Lab

Evolution of Deep-Sea Fishes

Research in the lab  focuses on the evolution of fishes that inhabit the deep sea, as the extreme habitats of this environment have produced fascinating evolutionary events among the 4000 - 6000 species of marine fishes that have invaded this realm (e.g., telescopic eyes, bioluminescence, hermaphroditism). We use phylogenetic hypotheses as frameworks to investigate a breadth of evolutionary questions related to organismal diversity and diversification. Our work focuses on exploring a number of evolutionary topics related to fishes that inhabit the deep sea, including; estimating divergence times, temporal changes in diversification rates, character evolution, correlations between speciation rates and evolutionary adaptations, ecological habitat shifts, and biogeography.


Recording a live podcast with high school interns.

what the fish? podcast (2012-2013)

The  "What The Fish?" podcast was a bi-weekly show that discussed the wonderful biodiversity, biology, and evolution of fishes. The "What The Fish?" podcast series can be subscribed to for free on iTunes, accessed from The Field Museum or listened to and downloaded below. Each podcast had an accompanying blog that focuses on the topic of that specific podcast, which can be read at The Field Museum website. 

When most people hear the word fish, they think of Nemo (clownfish), tunas, cichlids, and sharks. Everyone knows what a fish “is”, but why? It turns out that identifying the characteristics that define fishes is a daunting task, and with good reason! Fishes, as we think of them, are actually a paraphyletic or "unnatural" group. When scientists say “fishes”, they are discussing a group of organisms that includes all the descendants from a common ancestor.  So, the correct grouping of fishes includes us, the tetrapods (amphibians, turtles, crocodiles, birds, squamates, mammals, and countless extinct forms).

Yes, you are a fish. Now that your view of the world has been forever altered, let us explain. In general, there are three main groups of fishes still living today; the cartilaginous fishes (e.g., sharks, rays, skates, chimeras), the ray-finned fishes (e.g., goldfish, tuna, cichlids, clownfish, and our beloved anglerfish from the logo), and the lobe-finned fishes (e.g., coelacanths, lungfishes, frogs, birds, humans).  While terrestrial (or land) vertebrates such as frogs, dogs, and humans are classified as tetrapods within the lobe-finned fishes evolutionary lineage, we owe our earliest vertebrate origins to an aquatic environment. In short, just as humans are mammals, mammals are tetrapods, and tetrapods are all fishes. Welcome to the club!

As ichthyologists, scientists, and researchers that study fishes, we primarily study the cartilaginous fishes (greater than 1,000 species), the aquatic lobe-finned fishes (e.g., lungfishes, coelacanths, eight living species), and the ray-finned fishes (greater than 35,000 species). This podcast series will predominantly focus on fishy issues related to these evolutionary lineages. Fishes have thrived in aquatic environments that vary from the rivers and streams near your backyard to the deepest recesses of the ocean. The evolutionary history, biology, and ecology of fishes are as diverse as they are fascinating, and we look forward to discussing the vast biodiversity of fishes with you. Thanks for listening, and enjoy this ongoing podcast series!

Fishes use the same five major senses that all humans have: hearing, sight, smell, taste, and touch.  But for fishes, all of these senses differ somewhat from our normal day-to-day experience. Quite simply, living in a liquid environment is a very different thing than living in a gas (air) environment.  Think about the difference between smell and taste.  At some level tasting is like smelling wet things.  How different are these senses when you are already wet or underwater?  From an evolutionary or anatomical perspective, they do have fundamental, different origins and innervations, but because of their aquatic lifestyle these senses have more overlap in fishes when compared to humans.  Given this similarity, one of the most striking differences is that fishes actually cover various parts of their bodies (ranging from their skin to specialized barbels, whiskers, or fin rays) with taste buds rather than just focusing on the tongue like we do.  The whiskers of a catfish, like the one shown here, allow these fishes to taste the mud that they are digging around in.  Would you want to drag your tongue around in the mud?  We wouldn’t either.

Humans actually have more than five senses.  For example, we have sensors for balance, temperature, and pain, but the five main senses dominate our daily lives and take up more relative sensory area in our brains. Fishes have two other major senses that are not found among the senses we experience: electroreception and mechanoreception (or distance touch).  Electroreception is less common among fishes, but it is comparatively easy to grasp. This electro-sensitive system is much like a beach comber searching a sandy beach for valuable metals.  Fishes use this system for a variety of reasons, but many fishes use this sense for hunting or gathering.  A hammerhead shark or paddlefish will move the enlarged regions of their heads to search for small electrical signals in the water coming from animals respiring or moving.  Specifically, fishes respiring underwater produce a small ionic charge that will stimulate electroreceptors, which allows a predator to find a sand dab or sea robin buried under the sand. Mechanoreception is the sensory system that allows fishes to school, fishes to measure the surrounding current to hold their position in a moving stream, and fishes in the dark (e.g., deep-sea or caves) to find cave walls or rocky outcroppings. This is carried out by particular hair cells that are housed in a series of tubed scales along the side of a fish, found on the surface “pit organs” that cover the skin of some fishes, and distributed within bony canals in the head of a fish.  These specialized hair cells or neuromasts are stimulated (bent/displaced) by the change in motion of water over the structures.  This bending of the hairs in particular directions tells the fish that their schooling partners are changing direction or that a shark is quickly approaching, hence its common name of distance touch.  If you are like us, you wish that you had these other wonderful vertebrate senses; but alas, they only work when you live underwater…

Bioluminescence, the production and emission of light from a living creature, is widespread among different groups of marine fishes (e.g., anglerfishes, flashlight fishes, dragonfishes). Most organisms produce light through a chemical reaction between luciferin (a small molecule) and oxygen. The enzyme luciferase speeds up this reaction, resulting in the production of light. But unlike the incandescent lightbulbs in your home, this light gives off almost no heat. Some fish species have the ability to produce the chemical compounds necessary for bioluminescence themselves (such as lanternfishes), while others rely on symbiotic bacteria to create and generate light (including the beloved anglerfish in our logo).

The majority of bioluminescent fishes are found in the deep sea. Below 1,000 meters there is no visible sunlight in the ocean. As a result, many organisms that live below this depth have evolved bioluminescent structures, and fishes use this light in a variety of ways. Some fishes use light for camouflage, specifically counterillumination.  This is where the fish emits light around its belly to match any light coming from overhead, making it invisible to predators looking upwards for shadows in the water column. Others use light to attract and catch prey, such as the beckoning luminescent lure of the anglerfish. Fishes will even use light for communication in order to recognize each other in the darkness of the deep or to communicate with potential breeding partners.

For most fishes, reproduction involves eggs and milting, which is like crop-dusting with sex cells (aka gametes). The vast majority of fishes are oviparous, which means they lay eggs that are fertilized and develop outside the mother's body. In these situations, males typically milt, which is the release and spreading of their gametes, onto the eggs that have been deposited in the environment. In ovoviviparous fishes, the eggs develop inside the body of the mother, and male gametes have to be passed into the females’ body through specialized structures, such as claspers (modified pelvic fins) in sharks or gonopodiums (modified anal fins) in guppies. Live birth (viviparity) has also evolved in a number of lineages of fishes, including sharks, guppies, and rockfishes. In viviparous fishes, the young develop within the mothers’ body.

While most fishes have separate sexes, a number of lineages are simultaneous or sex-switching hermaphrodites. Some fishes, such as clownfishes, can change their sex once during their lifetimes either from female to male, or male to female depending on environmental and/or behavior scenarios. A small number of fish species are simultaneous hermaphrodites capable of producing both male and female gametes at the same time (e.g., lancetfish, some species of moray eels as seen above). Scientific studies have identified that at least some of these species (e.g., the mangrove killifish Kryptolebias marmoratus) are capable of self-fertilization!

Sharks, and cartilaginous fishes in general, have long mesmerized scientists and the public alike. They are fascinating creatures!  Fossil remains indicate that sharks have been evolving on this planet for well over 400 million years. They have been described in popular culture as "perfect killing machines," and it is hard to argue with their abilities to hunt and secure prey of all shapes and sizes. Be it the incredible filter-feeding of the immense Whale and Basking sharks or the pure power and incredible bite of the Great White Shark, few organisms in nature portray an aura of such efficiency. Sharks are among the earliest known jawed-vertebrate lineages, and since their initial evolution, they have wasted no time in putting those jaws to work. After 400 million years they still remain some of the oceans most incredible predators with no signs of slowing down. 

However, there are more to sharks then just teeth! A number of lineages have independently evolved venom, including the horn sharks and angel sharks. The horn sharks release venom out of spines that stick out from each of their dorsal fins, making them an unattractive meal for even larger predatory fishes. The spines of the dorsal fins in some squaliform (or dogfish sharks) are also known to be venomous, including species within the lanternsharks. Sharks have also independently evolved bioluminescence, the ability to generate and emit light, as they have invaded the deep sea. These include predominantly deep-sea taxa, such as the lanternsharks and the bizarre Cookie Cutter Shark that sucks on to prey and rips off hunks of flesh before speeding away. These deep-sea sharks all use bioluminescence to hide from potential prey items, to avoid being eaten themselves, and for communication.

The Field Museum's Division of Fishes houses approximately 2.5 million specimens of fish, including whole specimens in alcohol, skeletal specimens, tissue samples, and cleared and stained material. That is a lot of fishes! But the fishes did not just arrive overnight; scientists and researchers have been adding to the collection at The Field Museum since 1894. Museum collections serve as records of the natural world, as well as critical resources for scientists wanting to study the biodiversity of the planet. The fishes collection has grown through continued fieldwork by ichthyologists that use a vast array of tools and strategies for sampling living and extinct fishes from around the world. Tune into our podcast this week with a special paleoichthyological guest, Sarah Gibson of the University of Kansas. Listen to us as we discuss the many different ways we collect fishes in the field. 

For ichthyologists and fish enthusiasts everywhere, Disney-Pixar's Finding Nemo is one of those rare pieces of art and cinema that captures the essence of being a fish from a dazzling number of perspectives. It is clear from the very first frame that great care and attention to detail was taken with each marine species and their oceanic habitats. Sure there are the occasional liberties taken, such as the bizarre combination of different deep-sea fish species to form the mutant anglerfish that terrorizes Marlin and Dory.  But overall the attention to detail in this movie is spectacular from a fishy point of view. Scales shimmer and reflect light, movement is superb, and more often than not each fish is recognizable down to an exact species. For this episode we recorded a commentary track that can be played alongside the movie where we discuss our favorite scenes, the science behind the fishy stars, the plausability of plot points from a biological point of view, and just some plain old fashioned yammering.

Scientists at The Field Museum have the wonderful opportunity and responsibility to describe and explain recent discoveries in the fields of anthropologybotanygeology, and zoology to a worldwide audience of visitors through both our physical building in Chicago and the virtual world through our website, games, and other digital media such as the What the Fish? podcast.  For this episode, we were joined by Dr. Shannon Hackett, Associate Curator of Zoology, and Paola Bucciol, Exhibition Developer. We use the reopening of the Ronald and Christina Gidwitz Hall of Birds to discuss the interplay between the scientific and exhibition departments and the evolution of museum exhibitions.

The creation of new, specimen-rich, and engaging exhibits is a large investment.  Teams of Museum staff from exhibitions to research to information technologies to institutional advancement (to name just a few) all have to work together to create or modify permanent or temporary exhibitions.  It requires a lot work, time, and energy from a lot of creative people, and the museum has scores of small to large exhibitions on display each year.

One of the major goals of our exhibitions is to communicate our core principles and, where possible, the state of the art in the natural history disciplines to the public. Natural history museums began as a way to highlight biological, geological, and cultural diversity to people that might never have any other opportunity to view dinosaur skeletons, lions, or meteorites.  

While technology has made the world a smaller place, The Field Museum still provides the rare opportunity to see the actual animals, gems, or ancient tools. The Field Museum has more than 24 million specimens and artifacts, and these specimens and the research and collection staff that work with them all have stories to tell.  Some of our spectacular and best known specimens such as Sue the T. rex or The Tsavo Lions have well known stories, but there are thousands of additional stories that can be equally captivating or provide the “eureka” moment in a scientific discovery. Examples can be found throughout the exhibitions (e.g., Tiktaalik in the Evolving Planet exhibit) or our website (e.g., A Bird of Paradise with John Bates in The Field Revealed series).  For this reason, we emphasize Field Museum collections and research when we develop and expand our scientifically vetted physical and virtual exhibitions.

If you get a chance, stop by The Field Museum and check out some of the exhibitions that our own What the Fish? team and guests have recently worked on - the recently opened Ronald and Christina Gidwitz Hall of Birds or the Spring 2013 opening of The Creatures of Light.

Ever been swimming at your favorite local spot and encounter a piranha? Believe it or not, this happens across North America all the time - not just in late night B-movies! So how does a fish that is native to South American freshwater rivers find itself living in a Missouri pond? Often these invasive species (a term that describes biodiversity that is introduced into a non-native environment and locale) are simply dropped off by pet-owners that are releasing them into the wild.  In some cases invasive species take hold in a non-native environment purely through accidental circumstances. Occasionally, invasive species are purposefully placed in a locality because someone thought they would serve a specific positive purpose. For example, mosquitofishes (Gambusia affinis) have been frequently introduced in non-native habitats because people wanted them to control mosquito populations. Join us and our special guest, Caleb McMahan, as we discuss this environmentally important topic.

Introducing non-native species frequently has negative effects for the local environment and biodiversity. Invasive species can dramatically alter the fragile ecosystems they are introduced into and severely threaten native wildlife. One example of an introduced fish that has reeked havoc on the native fishes of Illinois is the Round Goby (Neogobius melanostomus). The Round Goby was introduced into the Great Lakes (including Michigan) through freighter vessels traveling from the Black Sea. Once the Round Goby was accidentally brought to the lakes they began spreading at a rapid pace. Unfortunately, the increase in these invasive gobies has harmed many native fish populations, such as the Mottled Sculpin (Cottus bairdi). Round Gobies are voracious predators on the eggs and fry of other fishes and they are fiercely territorial with their spawning sites.  This creates competition with native fishes for reproductive space. Another invasive species in Illinois is the Grass Carp from Asia (Ctenopharyngodon idella), which was purposefully introduced in the United States in an effort to control aquatic weeds. The introduction of the grass carps into non-native habitats was carefully controlled, and many of the  introduced populations were gentically modified to be sterile in an effort to curb unwanted population growth in the wild. Despite these precautions, populations of Grass Carp have spread across the United States since their intial introduction in the 1960's.

The vast expanse of the seas is our destination, and uncontrollable terror is our goal. Join us as we descend into the madness that only total darkness can bring. The deep holds many secrets, and we shall share them with you...including inspirations for sea serpents (Oarfishes - including the photo here taken by our own Leo Smith), fierce predators that hide behind shimmering lights (Anglerfishes), and even the secrets to zombification (Pufferfishes). Caution, don't try zombification at home. Seriously, we don't recommend it. We hope you enjoy our special Halloween and spooky season podcast!

Among fishes, the different types of food and the ways in which they are consumed are as incredibly varied as the fishes themselves. Some fishes are vegetarians, including the Piranha relative the Pacu, while others are ferocious carnivores, such as the African Tiger Fish. Fishes often have very specilized dentition and feeding structures depending on their source of food. For example, fishes that crush hard crustacean shells may have large boulder-like teeth. Filter feeding fishes, such as the Whale Shark seen below, have evolved fine filamentous structures to help sift through plankton. Overall, fishes eat almost anything you might find in an aquatic environment, and they do so efficiently!

One of the primary reasons that we here at What the Fish? are fascinated with the evolutionary history of life on Earth is that it provides a context and scientific hypothesis from which we can further study the wonderful biodiversity of fishes. For example, if we have a working scientific hypothesis of how different species of clownfishes are related to one another, we can address questions surronding the number of times clownfishes have formed symbiotic relationships with anemones. But how do we build these evolutionary trees of fishes, such as the one seen below? Well there are various different kinds of scientific data that can be used to infer evolutionary relationships through time (e.g. variation in the sequence of DNA/genes, anatomical features, behavioral traits) that scientists around the world collect in order to support these hypotheses. Shared anatomical characteristics, such as the position of a spiny-rayed dorsal fin, may be indicative of common evolutionary ancestry, and scientists use this evidence to produce hypotheses regarding the evolution of life on Earth.

Although they vary in size, morphology, and type (e.g., plates, scutes), many fishes have evolved thick armor-like scales that help protect them from their aquatic environment and potential predators. Many fishes that live in and around the bed of aquatic environments utilize armor to protect their bodies from loosing scales as they burrow and scrape along rough substrates and potentially rocky or jagged environments, such as catfishes and poachers. Other armored fishes may sacrifice mobility for a tank-like body that makes them nearly inedible to nearby predators. For example, the aptly named boxfishes have scales are hexagonal in shape and result in an armor that looks like a bee's honeycomb. The body armor of fishes are so effective that various scientists and researchers have been investigating the morphological properties of fish scales, such as those in bichirs, to aid with the development of stronger body armor for humans!

In previous What the Fish? podcasts, we have covered topics ranging from  what makes a fish a fish to aquatic bioluminescence and sensory systems.  We have augmented these fishy topics with discussions surrounding the role scientists play in developing content for museum exhibits and the excitement, hardships, and discoveries made during fieldwork.  Herein, we present the first part of our What the Fish? collections-based research episodes exploring the value and role of Museum collections and their associated data in scientific investigation. To help us discuss the topic of the analysis of collections data, we are joined by Hannah Owens who is a doctoral candidate at The University of Kansas. Hannah combines museum collections data, fisheries data, and ecological data to explore the role of climate change in the evolutionary history and the biogeography of fishes. Hannah's research combines ecological niche, macroevolution, and climate data to explore the "fish stick" fishes or cods, hakes, and relatives from the order Gadiformes.  

What are collection data, and why are they useful? When ichthyologists conduct their fieldwork, they collect much more than the specimens themselves.  Fish biologists minimally collect geographic (e.g., latitude and longitude) and temporal (date and time) data, but they frequently collect habitat information, depth, salinity, temperature, visibility, and a wealth of other ecological data that are databased along with the specimen identification and information in databases such as those at The Field Museum.  Individually, these records are valuable for ichthyologists interested in the distribution or biogeography of particular species, but when taken in aggregate (e.g., through pooled resources such as GBIF) these data can be explored in "meta-analysis" that can inform countless ecological and evolutionary studies. For example, predictive modeling of organismal distributions has brought these data together to better predict the expansion of introduced species, to predict the potential presence of animals or plants in unexplored regions, and to test for the impacts of climate change. These predictions and analyses are only going to become more critical as species continue to be introduced, species distributions continue to shrink toward extinction, fieldwork becomes more difficult, or large-scale climate change becomes increasingly studied. These collection data, based on well-curated specimens, are the only verifiable data that can be brought to bear on these questions.

Distributional data that lack preserved specimens (vouchers) can always be questioned at a later date because the species identifications cannot be reassessed. This same value in being able to reassess species identifications based on whole-specimen vouchers is equally important for genetic or DNA-based research where the discovery of cryptic species (morphologically similar species representing  diagnosable and genetically different forms) is a frequent occurrence.  In cases where there are no voucher specimens to examine, researchers are required to return to the field to corroborate their molecular hypotheses.  These are just a few of the cases where specimens and their associated data have contributions well beyond ecology and evolutionary biology.  Listen to the podcast to learn additional examples! 

In our last episode, we discussed the role of collection data for scientific investigation. In this episode, we explore the value of the research on museum specimens and artifacts themselves, focusing on the use of specimen examination and evolutionary hypotheses to better explain the natural world. To help us discuss this topic, we are pleased to be joined by Dr. Peter Makovicky, The Field Museum's own Curator of Dinosaurs and Chair of the Department of Geology. Phylogenies (a hypothesis of how life is related evolutionarily) are crucial for predicting the distribution of incompletely studied organismal characteristics ranging from the presence of venom in fishes, to feathers on dinosaurs, or how the anatomy of eyes change in the deep sea as a result of selective pressures. In other words, knowledge of the evolutionary relationships of life allows for effective predictions about the unstudied characteristics of species. Museum collections are a critical component of this work, from the initial collection of samples used to infer our hypotheses of how life is related (e.g., whole specimens, tissues used to extract DNA for genetic work) to our ability of accessing this material again to test and explore evolutionary hypotheses.

An example of the biological questions we can explore in this manner is tracing the evolution of venomous fishes. By looking at venomous fishes from an evolutionary perspective, we generated a much more accurate picture of fish venom evolution than was previously suggested using a strictly observational approach. To explore venom evolution, we began by taking a major stab at the fish tree of life by analyzing all suborders and known venomous groups of spiny-rayed (Acanthomorpha) fishes for the first time. Using the resulting family tree of fishes as a framework, we mapped the species that were known to be venomous on to this DNA-based tree. This provided an initial estimate of how many times venom evolved and allowed us to predict which fish species beyond the "knowns" should be venomous or could possibly be venomous. To test these predictions, we explored the museum collections and dissected scores of specimens to look at the detailed anatomy of fish venom glands and clarify how many times venom evolved on the fish tree of life. By working our way down the fish tree of life by comparing ever more distantly related fishes from the known venomous fishes, we could pinpoint the number of times venom evolved, the exact groups of fishes that are venomous, and revise the identity of venomous fishes. This type of research is occurring world wide based on the collections at The Field Museum, and similar institutions that house, maintain, and allow access to museum specimens for scientific research. This example is just one of the many stories surrounding research done at The Field Museum with collection-based research.

Becoming a scientist or working in science is never a straight forward path: appreciation of the natural world, hobbies, high school jobs, science fiction and random life events all come into play. We discuss these sinuous paths into science with a special live audience, The Field Museum's Youth Design Team summer interns.  We hope that our stories were a source of science and fishy inspiration!

The Youth Design Team (YDT) is part of the TakeThe Field programs here at the Museum and is designed in collaboration with the Pearson Foundation's New Learning Institute. YDT takes teens behind the scenes to interact with scientists, designers, media producers, researchers and other teen volunteers like themselves. Teens hear firsthand what it’s like to roam the plains of Africa and tromp through the forests of South America. In addition, they participate in the process of designing an exhibit from scratch! To learn more about the Youth Design Team program visit the TakeTheField page on Facebook!

The recent capture of a living giant squid on video through a joint venture by scientists from Japan and the United States has captured the imagination of people worldwide, providing new insights into the biology and life history of this enigmatic creature. Cephalopod (e.g., squids, cuttlefishes) expert Janet Voight joins us to discuss this discovery, including what we know about giant squid biology so far and what these new videos can teach us about how giant squids hunt and avoid predation themselves. Of course oceanic life is more diverse than just fishes, so this episode we take some time to discuss the various invertebrate denizens of the deep, including cuttlefishes and wood-boring clams.

Fishes have long fascinated biologists that study the science behind reproduction, as we discussed in Episode 4. However, how fishes reproduce is not the end of the story. The process from birth to individual survivial is as equally varied as the ways fishes reproduce. The majority of fishes lay eggs in the water column, which may be sticky so they can be deposited on some form of shelter, such as a drifting log or piece of kelp (e.g., flyingfish, killifishes, clownfishes). Others give birth to live young (e.g., guppies, dogsharks, coelacanths). Following birth, the juvenile fishes of many species find themselves on their own, fighting to survive. These larval and juvenile fishes may be morphologically similar to their adult forms (e.g, minnows, cichlids), or their anatomy may dramatically differ as the larval forms of many marine fishes find themselves inhabiting completely different habitats than those they will occupy when they are adults. Other fishes actually protect their young, such as the famous example of seahorses and seadragons, where males shelter and care for the eggs in modified poches until they hatch. Stranger still, is the marine engineer goby (Pholidichthys), where two adult fish live in a colony with their juvenile offspring. The juveniles have been observed gathering food during the day and bringing the nutrients back to the reproductive adults that are burrowed deeply underground, that then proceed to feed off of "slime" covering the bodies of the juveniles. No one ever said parenting was glamorous, even for a fish!

Creatures of Light is a temporary exhibition that focuses on the incredible diversity of bioluminescent and biofluorescent organisms across the tree of life.  It explores the evolution, function, and habitats of bioluminescent and biofluorescent animals, fungi, and single-cellular life.  This 2013 exhibit will run at The Field Museum from March 7 until September 8.  The exhibit was organized by The American Museum of Natural History in collaboration with The Field Museum and the Canadian Museum of Nature.

Our own What the Fish? contributor Leo Smith was the lead curator for the exhibit at The Field Museum, and Matthew Davis and Eric Ahlgren contributed to the content, development, and specimen presentation.  The exhibit begins with terrestrial fungi and insects, eventually working its way down into the famous Bioluminescent Bay of Vieques Island (Puerto Rico) and the abyssal depths of the ocean.  While the Creatures of Light exhibit is at The Field Museum, nearly 100 preserved bioluminescent fishes and invertebrates (jellyfishes, salps, squids, etc.) from our vast research collections have been mounted and presented in a 20+ feet long cabinet that beautifully displays these rarely seen animals (many shown above).

For the podcast, we discuss the development of the exhibit, focusing on the special specimen additions that are exclusive to The Field Museum. If you want to hear or read more about bioluminescence, check out Episode 3: You Light Up My Life.

On February 15, 2013 a fireball exploded over the Chelyabinsk district of Russia. The shock wave caused significant damage and injuries to many in the area. This meteor was the largest object to fall on Earth in almost 100 years, with an estimated mass of about 11,000 metric tons. On April 9, The Field Museum received several pieces of the Chelyabinsk Meteorite totaling about two pounds thanks to a generous donation from meteorite collector Terry Boudreaux. Many Antarctic icefishes, such as species in the suborder Notothenioidei, frequently live in water that range in temperature from –2°C to 4°C due in part to the evolution of an antifreeze glycoprotein that is found in their blood, with many species in this group possessing little to no hemoglobin in their bloodstream. Much of the biodiversity that is found in the Southern Ocean are thought to be highly susceptible to potential long term changes in climate over time, icluding phytoplankton, and fishes.

In this episode we welcome special guest Dr. Kevin Tang (Assistant Professor University of Michigan Flint) to discuss a new hypothesis that addresses a longstanding fishy paleontological mystery, the spiral-tooth whorls of the extinct cartilaginous fish species Helicoprion. From there we weave a tangled web of fieldwork parasite paranoia and encounters with large logs.

We here at "What the Fish?" love museum exhibits. But as it turns out, our favorite types of exhibits are incredibly varied, reflecting a lot of our personal opinions and preferences. Tune in to our latest episode to hear us discuss and argue about our favorite types of museum exhibits, and what we hope to see when we visit a museum. 

While a lot of our research involves museum specimens that have long since expired, we do enjoy taking care of, breeding, and observing live fishes! In this episode we are joined by professional aquarist Steve Ehrlich to discuss the in’s and out’s of the fishkeeping and aquarist hobby. We talk about working behind the scenes at some of the best aquariums in the United States (e.g., Shedd and Birch Aquarium), how to breed and raise fishes, and secrets to maintaining a healthy aquarium at home. Whether you are a beginner looking to get started or an expert fishkeeper, we welcome you to join our fishes school!

Within the evolutionary history of vertebrates, the transition from an aquatic environment to a terrestrial habitat significantly impacted the course of vertebrate evolution on Earth. Scientists have been studying this transition intensively from an incredible variety of angles, such as biochemistry, paleontology, functional morphology, and evolutionary relationships of these incredible creatures. In this episode we discuss some of the factors and science that influenced this incredible turning point in vertebrate evolution. 

Venomous animals are captivating because of the fears their toxins provoke and the potential pharmaceutical benefits their venoms contain. Most people conjure up snakes or scorpions when they think of venomous creatures, but recent scientific work has demonstrated that there are at least 15x as many species of venomous fishes than previously estimated, including the Blue Tang (Paracanthurus hepatus) that Ellen DeGeneres made famous in Finding Nemo. In fact, Dory is just one of more than 3,000 species of venomous fishes, making them more species-rich than venomous snakes and scorpions combined. Although our knowledge of venomous fishes is in its infancy, it is clear that their venoms should be regarded as a tremendous new source of pharmaceuticals because of the incredible diversity of fish venoms and their moderate levels of toxicity.

We here at "What the Fish?" have had a great time discussing all of our favorite fishy things in life, and we hope you have enjoyed the content we put together. We are ending "What the Fish?" on its 26th episode because that marks one year's worth of shows, and it coincides with Beth, Leo, and Matt leaving The Field Museum for other fishy adventures.

In this final episode, we talk about the creation of this podcast series, behind the scenes stories, and disccuss how to disseminate science and research to the public. Thank you for listening to this audio podcast series, and keep an eye out for future content from us as we move on to new endeavors. 

Public outreach and Exhibit design

At The Field Museum, I was a content advisor for the temporary exhibit "Creatures of Light", currently on display through January, 2014. I was  an active participant with the public outreach program "Dozin' with the Dinos."  I have given public presentations regarding the biodiversity of deep-sea fishes, including hands-on experience with collections material.  I also led tours of the Collections Resource Center, with the goal of informing and educating the public regarding the importance of natural history collections.  Follow the link to learn more about The Field Museum's "Dozin' with the Dinos" program.


During my time at Louisiana State University's Museum of Natural Science, I led public outreach seminars regarding the biodiversity, evolution, and ecology of fishes. While at the University of Kansas, I participated in the creation of handouts and websites designed to teach high school students about evolution, molecular phylogenetics, and the diversity of fishes.

St. Cloud State University, 720 4th Ave South, Wick Science Building, St. Cloud, MN 56301. © MP Davis 2016