Wednesday, June 27, 2012

Steroids Won't Help If You're a Loser

The more we study physiology and behavior across groups of animals, the more we find we have in common in the types of behaviors we express and the biological machinery of how our bodies influence what behaviors are expressed and when. But similarity does not mean the same. Sometimes seemingly small physiological differences can have big behavioral consequences.

A snuggly California mouse pair.
Photo from the Marler lab.
A lone wire-walking white-footed mouse.
Photo by the National Park Service.
Take the California mouse and the white-footed mouse, for example. Both are small grayish to brownish species of North American deer mice (the Peromyscus genus). But behaviorally, these species are quite different. One noticeable difference in their behavior is that California mice are very territorial and dominant towards intruders, whereas white-footed mice are more welcoming of other mice (or at least more ambivalent to their presence). These species also differ in how they respond to dominance challenges: California mice that win a challenge (by getting their opponent to show submissive behavior) are more likely to win future challenges (this phenomenon is called the Winner Effect). However, white-footed mice have the same probability of winning or losing a challenge regardless of whether they won or lost the previous one. Interestingly, the experience of winning causes the levels of testosterone (a steroid hormone) to surge in California mice, but not in white-footed mice. Could this difference in testosterone explain this difference in behavior between these two species?

Cathy Marler and her colleagues at the University of Wisconsin at Madison recently explored this question. They compared four groups of male mice: (1) California mice that won three challenges and had a saline injection after each win, (2) white-footed mice that won three challenges and had a testosterone injection after each win, (3) white-footed mice that won three challenges and had a saline (without hormone) injection after each win, and (4) white-footed mice that were handled by researchers three times (and had no dominance challenges) and had a testosterone injection after each time they were handled. Then they placed each mouse with a new challenger and measured what percentage of males in each group were dominant versus subordinate.

Most California mouse males that have been previously dominant and had
no hormone treatment win a future dominance challenge (black bar).
White-footed mice (grey bars) are only likely to win their next dominance challenge
if they had previously won AND had additional testosterone (W+T), but not if they
won without added testosterone (W+S) or had testosterone without wins (H+T).
Figure from Fuxjager et al., 2011, Proc. R. Soc. B.
Marler and her colleagues found that similar to the natural state, white-footed mice that won three times and were not injected with testosterone were less likely to win a later challenge than California mice that also won three times and were not injected with testosterone. But, white-footed mice that won three times and were injected with testosterone won their next challenge as often as the California mice did! Presumably, the California mice had their own natural surge of testosterone whenever they had a winning experience and the testosterone injections given to the white-footed mice after their wins mimicked this effect and increased their odds of winning later.

However, testosterone injections alone were not enough to increase the chances of winning: the white-footed mice that had testosterone injections without winning challenges were just as likely to lose their next challenge as those that had saline injections and won previous challenges. It’s the combination of winning experience paired with a surge of testosterone that is the winning formula. You can think of it this way: When (fictional) scientists gave frail Steve Rogers "Super Soldier Serum" to turn him into Captain America, it only worked because Steve Rogers was already a winner at heart. Had they given the serum to someone less remarkable, Michael Cera, for example, they just would have ended up with this:
Michael Cera's attempt to be Captain America. Photo by Gage Skidmore.
So what does this all mean? For one thing, it appears that white-footed mice have all of the necessary brain-wiring to show a Winner Effect in the same way that California mice do, but they don’t produce the testosterone surge to activate it. This opens up a bunch of new questions, like: Why don’t white-footed mice have a testosterone surge after winning? Is there some aspect of their lifestyle that would make such a testosterone surge costly? How does the body know to release testosterone in response to a social experience anyway? Other than testosterone, what makes a winner a winner?

In the end, the experience of winning is critical to the Winner Effect: Testosterone alone won’t help you win your next challenge. So don’t think steroids are gonna help you if you suck at your sport of choice. You have to already be a winner for extra testosterone to help you win… and at that point, who needs it?

Want to know more? Check these out:

1. Fuxjager MJ, Montgomery JL, & Marler CA (2011). Species differences in the winner effect disappear in response to post-victory testosterone manipulations. Proceedings. Biological sciences / The Royal Society, 278 (1724), 3497-503 PMID: 21490015

2. Oyegbile TO, & Marler CA (2005). Winning fights elevates testosterone levels in California mice and enhances future ability to win fights. Hormones and behavior, 48 (3), 259-67 PMID: 15979073

Wednesday, June 20, 2012

The Age of Aquariums: Amazing Animal Watching Vacations Part 3

Oceans are the largest ecosystems on the planet. They produce half of the oxygen we breathe and contain 97% of the world’s water. Oceans provide a sixth of the animal protein in human diets and are the most promising source of new medicines to fight cancer and other diseases. On top of all that, they absorb about a third of the carbon dioxide emissions we produce, which helps reduce the rate of climate change. In a nutshell, we need them.

Pacific bluefin tuna return to the aquarium in the newly-transformed Open Sea exhibit at the Monterey Bay Aquarium. The Pacific bluefin is a commercially valuable species, but due to overfishing, Monterey Bay Aquarium's Seafood Watch Program has put all bluefin tunas on the "Avoid" list. © Monterey Bay Aquarium/Randy Wilder
Unfortunately, these ecosystems are vulnerable and are becoming increasingly degraded. Overfishing of many species is not only destroying populations of those species, but also the many other species that depend on them. Destructive fishing methods, pollution, soil runoff and increased water temperatures are destroying the delicate coral reef communities that serve as nurseries for a wide range of ocean life. These are not small problems in a few isolated places. For example, up to 88% of the Southeast Asian coral reefs are now threatened.

Last week we talked about the role of aquariums in teaching us about wonderful marine habitats and animals, but simply learning about these environments is not enough if we can’t keep them around and healthy for future generations. Many aquariums play a vital role in conservation and research. Here are a couple of leaders in the field:

The Monterey Bay Aquarium:

The Monterey Bay Aquarium in Monterey, California is on a mission to inspire and support ocean conservation. Their exhibits devoted to the varied habitats around the Monterey Bay include a living three-story kelp forest, a Monterey Bay Habitats exhibit, and a playful otter exhibit. The Vanishing Wildlife window shows a ground-floor view of sea turtles, sharks and tunas, all magnificent animals that need our protection if their populations are going to survive. This exhibit shows how researchers, conservationists and people working in the fishing industry work together to support these species and others.

An adult Southern sea otter that was reared by a
surrogate mother through the aquarium's Sea Otter
Research and Conservation (SORAC) program has
successfully given birth to her second pup in the wild.
©Monterey Bay Aquarium/Randy Wilder
The Monterey Bay Aquarium has an extensive Research and Conservation focus, including a dozen programs. One of these programs, the Sea Otter Research and Conservation (SORAC) program, has been studying and rescuing southern sea otters since 1984. Southern sea otters are a keystone species, eating sea urchins and other invertebrates that graze on kelp forests. Yet in the early 1900s, sea otters were hunted until only about 50 otters remained along the California coast. Thanks to protection under international treaty and support by programs like SORAC, their numbers have grown to nearly 3000.

The New England Aquarium:

The New England Aquarium in Boston, Massachusetts (which uses the slogan “Protecting the blue planet”) has over 70 exhibits featuring animals from around the world. But they also have a number of programs to protect species and their habitats, rescue and rehabilitate wildlife, support research on wildlife medicine, research the effects of climate change, and support sustainable fisheries.

The New England Aquarium Endangered Species and Habitats Program has been working to protect and preserve ecosystems and conserve threatened animal species for over 20 years. Their conservation projects span the world and are all guided by understanding the biology of the system and collaborating with people that are affected by it. For example, Project Piaba has been working with Amazonian fishermen in Brazil since 1989 to create sustainable fisheries. Not only does this approach improve the health of the animal species and their habitats, but it helps the local people develop a more stable income by using their natural resources in a more sustainable way.

Coral reefs near Enderbury Island, Phoenix Islands Protected Area (PIPA)
©New England Aquarium/Dr. Randi Rotjan
Another great example is the preservation of the Phoenix Islands Protected Area (PIPA). Since their first visit in 2000, PIPA is now one of the largest marine protected areas in the world and an irreplaceable research site. Research at PIPA focuses on exploration, connectivity within the marine ecosystem and reef resilience.

Do you want to know what you can do to help protect our ocean habitats? The Live Blue program has a list of Ten Ways You Can Make a Difference.

For information on more great aquariums, check out last week’s post. For other animal watching ideas, go here and here.

Want to know more about ocean threats? Check these out:

1. Burrows MT, Schoeman DS, Buckley LB, Moore P, Poloczanska ES, Brander KM, Brown C, Bruno JF, Duarte CM, Halpern BS, Holding J, Kappel CV, Kiessling W, O'Connor MI, Pandolfi JM, Parmesan C, Schwing FB, Sydeman WJ, & Richardson AJ (2011). The pace of shifting climate in marine and terrestrial ecosystems. Science (New York, N.Y.), 334 (6056), 652-5 PMID: 22053045

2. Sylvia Earle’s book The World is Blue: How Our Fate and the Ocean’s Are One

Do you have a favorite aquarium? Tell us below and I might cover it in a future post.

Wednesday, June 13, 2012

The Age of Aquariums: Amazing Animal Watching Vacations Part 2

Below the ocean’s surface is a world more mysterious than the dark side of the moon and with more animal diversity than the Amazon rainforest. Over 70% of our planet is covered in ocean, yet fully 95% of our oceans remain completely unexplored. But we do know that the habitats animals adapt to are more vast than the open ocean (In fact, many more animals are by the coasts than out in the open ocean). There are shallow sunlit coastal waters and deep dark ocean trenches, coral reefs, estuaries, and even volcanoes! This variety in habitats has resulted in an amazing variety of some of the strangest and most mesmerizing animals on Earth. The best way to get a close look at them is to go to an aquarium, and there are many breathtaking aquaria to choose from. Here are a couple aquaria with exhibits that feature local habitats and animals (with more to come in future posts):

A cartoon of a cross-section of dark-water habitats. These places are really difficult to
get to.  Luckily, we can appreciate their residents at aquariums around the world!
Figure from Orcutt et. al, (2011) Microbiology and Molecular Biology Reviews paper.

The Aquarium of Western Australia (AQWA) in Perth:

The Aquarium of Western Australia (AQWA) in Perth, Australia has over 40 exhibits that focus on the amazing marine wildlife in the habitats off the Western Australia coast. Visit the Shipwreck Coast (Australia’s largest aquarium), the DANGERzone (where you can see some of the world’s deadliest sea creatures from behind protective glass), or the Marmion Marine Park (where you can interact with live animals in the touch pool).

Walk the coral reef exhibit for just $20! Photo by AQUA.
Are you one of those people that watch the divers in an aquarium exhibit and wish you could do that? You can at AQUA! If you want to get even more immersed in your aquarium experience, AQUA has awesome organized adventures. For just $20, you can walk underwater through one of the world’s largest coral reef exhibits (even if you don’t have diving experience). For a bit more, you can experience a guided snorkel or dive in AQUA’s shipwreck coast aquarium, coming face-to-face with sharks, stingrays, turtles and fish. And on Wednesdays, AQUA and Mills Charters run whale watching tours with guaranteed whale sightings.

AQUA has also taken an active role in animal research and conservation. The AQUA foundation is a non-profit organization that funded the development of satellite tags used to record the movements of great white sharks. This project discovered many new things about great white shark behavior, including that although they are capable of diving at least 570 meters deep (that’s over 6 football fields!), 80% of their time is spent within 10 meters of the surface! The AQUA foundation’s current project is the development of a specialized facility for the rehabilitation of sick and injured marine animals with the goal of returning them to the wild.

The Georgia Aquarium:

The Georgia Aquarium in Atlanta, Georgia, is the world’s largest aquarium, featuring more animals than any other aquarium. It has more than 60 exhibits, each designed to inspire, entertain and educate. The Ocean Voyager exhibit is the world’s largest single exhibit aquarium with 6.3 million gallons of water and featuring whale sharks, manta rays, sand tiger sharks, zebra sharks, humphead wrasse, spotted wobbegong sharks, bowmouth guitarfish, tasseled wobbegong sharks, leopard whiptail rays, and sandbar sharks. Whale sharks, the largest fish in the world, are especially extraordinary because you won’t find them in any other aquarium outside of Asia. Another notable exhibit is Georgia Explorer, the most interactive exhibit at the Georgia Aquarium featuring animals from local Georgia habitats. Here you can touch bonnethead sharks, cownose rays, and horseshoe crabs.

Whale sharks can grow to the size of a school bus!
Photo by the Georgia Aquarium.

The Georgia Aquarium also has a number of unique opportunities. If you are interested in pursuing a career in aquariums or even just seeing how they work, join a behind-the-scenes tour. Or put on a wetsuit and jump in the water with beluga whales and their trainers or swim with sharks in the Georgia Aquarium’s Ocean Voyager exhibit. If you’re looking for a memorable family experience, spend the night in an aquarium sleepover.

The Correll Center for Aquatic Animal Health is a state-of-the-art facility used through a partnership with the University of Georgia Veterinary Teaching Hospital to provide the Georgia Aquarium with a complete aquatic animal health program while training veterinary students, residents, and interns. It is the only integration of a veterinary teaching hospital within an aquarium. The Georgia Aquarium also supports, conducts and leads research trips. If you would like to meet Georgia Aquarium’s whale shark research team while participating in a whale-shark eco-tour in the Gulf of Mexico, they have trips planned for July 13-18 and August 24-29.

For more amazing animal watching vacation ideas, check this out. And for a relaxing animal watching stay-cation, try this. Tell us below about your favorite aquarium and I’ll cover it in a future post.

Want to know more about oceans and their ecosystems? Check these out:

1. GRAY, J. (1997). Marine biodiversity: patterns, threats and conservation needs Biodiversity and Conservation, 6 (1), 153-175 DOI: 10.1023/a:1018335901847

2. Orcutt, B., Sylvan, J., Knab, N., & Edwards, K. (2011). Microbial Ecology of the Dark Ocean above, at, and below the Seafloor Microbiology and Molecular Biology Reviews, 75 (2), 361-422 DOI: 10.1128/MMBR.00039-10

3. Zeppilli, D., Mea, M., Corinaldesi, C., & Danovaro, R. (2011). Mud volcanoes in the Mediterranean Sea are hot spots of exclusive meiobenthic species Progress In Oceanography, 91 (3), 260-272 DOI: 10.1016/j.pocean.2011.01.001

Wednesday, June 6, 2012

Decisions, Decisions

It doesn't take much to notice how different animals
can be... But look closer and you'll see how similar
they are too. Figure from O'Connell and Hofmann
2011 Frontiers in Neuroendocrinology paper.
Animals live in social environments that repeatedly present both challenges (like an aggressive neighbor) and opportunities (like a flirtatious neighbor). Although animals can usually respond to such challenges and opportunities in a number of different ways, there are patterns to how animals do respond. Scientists find that animals tend to make behavioral decisions that improve their chances of survival and reproduction. To do this, they evaluate the importance of what they perceive in their environment and their own internal physiology and then respond in ways that are appropriate to the social context.

Vertebrates (animals with spinal columns, such as mammals, birds, fish, reptiles and amphibians) have amazingly similar brain anatomy and physiology to control these behavioral decision-making processes. All five of these vertebrate groups have a social behavior network (a set of brain areas that are known to be sensitive to steroid hormones and to regulate social behavior) and a mesolimbic reward system (a brain system that uses dopamine to regulate motivation, among other things). When a vertebrate is faced with a social decision, these two brain systems work together as an integrated brain network called the social decision-making network.

Drawing of a rodent brain from the side showing brain areas in the mesolimbic reward system in blue and the social behavior network in yellow. Brain areas that are part of both systems are in green. Figure from O'Connell and Hofmann 2011 Frontiers in Neuroendocrinology paper.

Researchers Lauren O’Connell and Hans Hofmann from The University of Texas at Austin compared the neurochemistry of these brain regions across 88 vertebrate species, including mammals, birds, fish, reptiles and amphibians. In each of these brain areas for each species, they looked for the presence or absence of molecules involved in the chemical signaling of important behavior modulators (dopamine, estrogen, androgen, progesterone, vasopressin/vasotocin and oxytocin).

The researchers found that despite the diversity in the animals and their ecologies, their social decision-making networks were remarkably similar. One of the most striking similarities was that receptors for all of these behavior modulators were found in the same brain areas for almost all of the animals studied. This suggests that this common distribution pattern of where these receptors are in vertebrate brains is important for helping animals make decisions that improve their survival and reproduction regardless of what their social and environmental context is. This similarity may also explain, in part, why such diverse animals show similar behaviors in similar circumstances.

Drawing comparing animal brains from the front-view from front (left side ) to back (right side). Again, brain areas in the mesolimbic reward system are in blue, brain areas in the social behavior network are in yellow, and brain areas that are part of both systems are in green. Figure from O'Connell and Hofmann 2012 Science paper.

Although O’Connell and Hofmann found strong similarities across all vertebrates, that’s not to say there weren’t differences. Interestingly, the biggest differences were found between major groups of animals. For example, the fish species studied (although similar to each other) had a different distribution of dopamine-producing neurons than did all the 4-limbed animal groups (amphibians, mammals, birds, and reptiles). Additionally, birds and reptiles have more brain areas with vasotocin- and oxytocin-producing neurons compared to the other animal groups. Changes in where these neurochemicals are produced in the brain may correspond to changes in the animals’ social environments and the behaviors best adapted to such social environments.

The approach that O’Connell and Hofmann used in this study integrated decades of research on the brains, neurochemistry and behavior of nearly 100 different species, but it shows us that when we stand back and look at the bigger picture some remarkable patterns emerge. All vertebrates, from giraffes to tree frogs to iguanas likely have very similar brain systems that work in very similar ways to regulate very similar behaviors.

Want to know more? Check these out:

1. O'Connell, L., & Hofmann, H. (2012). Evolution of a Vertebrate Social Decision-Making Network Science, 336 (6085), 1154-1157 DOI: 10.1126/science.1218889

2. O'Connell, L., & Hofmann, H. (2011). The Vertebrate mesolimbic reward system and social behavior network: A comparative synthesis The Journal of Comparative Neurology, 519 (18), 3599-3639 DOI: 10.1002/cne.22735

3. O’Connell, L., & Hofmann, H. (2011). Genes, hormones, and circuits: An integrative approach to study the evolution of social behavior Frontiers in Neuroendocrinology, 32 (3), 320-335 DOI: 10.1016/j.yfrne.2010.12.004

Monday, June 4, 2012

Thank You for Reading!

I am honored to be awarded a Kreativ Blogger Award by a fellow science blogger at The Beast, the Bard and the Bot. I am so pleased that The Scorpion and the Frog is read and appreciated and to be recognized by science blogging peers is especially meaningful.

For those of you not familiar with the Kreativ Blogger Award, it is awarded to quality blogs by other bloggers in a pay-it-forward kind of fashion. Recipients then (1) Thank and link to the blog that awarded it to them, (2) Mention seven things their readers may not know about them, and (3) pay the award forward to seven more deserving blogs (and let them know they’ve been nominated).

As for things you may not know about me, I think I’ll stick with the animal theme of the blog:

  • I’ve been stalked by a pod of orcas (also known as killer whales). It was awesome!
  • I’ve been bluff-charged by a 600 pound Baird’s tapir. Also quite awesome!
  • I’ve been chased out of the rainforest by poop-throwing spider monkeys. It was not at all awesome. Well… okay. Maybe a little.
  • When I was walking to work in Panama a giant tarantula (called a matacaballo or “horse killer” by locals) fell out of my pants leg. He was pretty ticked off at me.
  • I worked at various animal hospitals for almost a decade. I got to be pretty good at subduing pets… Apparently that hasn’t translated to my interactions with wild animals.
  • I conducted my first zoology study at the National Zoo on tree shrews when I was in high school. I even presented my findings (with all the style that construction paper glued on poster-board can muster) at a national conference.
  • I interned at the Baltimore Aquarium when I was in college. It was the most Zen job ever.

And as for other blogs that deserve to be acknowledged, there are so many it is hard to choose. But there are a few that I think deserve special recognition:

There are so many more I wish I had more room. Take a moment to explore and appreciate the world of science blogs and everything they have to offer. And if you would like to further encourage your favorite science blogger, take a minute to nominate your favorite post for a 3 Quarks Daily Award. They are accepting nominations for “best science blog post of the year” until June 9th. If there is a post you want to nominate, enter the web address for that post (usually clicking on the post title will take you to the appropriate address) in the comment section of the announcement.

Stay curious, my friends.