Sagittal section of a Short-Tailed Opossum (Monodelphis domestica) at 14 days after birth. One of the final steps in the visualizing process we started here and here.  Fluorescent immunostaining for muscle (red), nerve tissue (green), and cell nuclei to visualize the outlines of the animal (blue). Check out those whisker pits!  Image credit: Curious Sengi.



Remember those Short-Tailed Opossum (Monodelphis domestica) neonates from last week?  After some chemical treatments, the specimens were frozen into a cutting compound, and then sectioned into 300 micron (0.01 inch) thick slices on the cryostat.  Here are three slices from the same animal.  The sagittal sections (parallel to the midline that divides the body into right and left halves) show all sorts of wonderful details such as the chain of the vertebral column in white, developing bones of the skull, liver, gut, eye, and tongue.  These sections look amazing, but they are not done yet!  Come back to find out what happens next.  Image credit: Curious Sengi.


A pair of Short-Tailed Opossum (Monodelphis domestica), 14 days postnatal.  Note the presence of hairs and whiskers on the face as well as the bones ossifying in the fore and hindfeet.  Image credit: Curious Sengi.

Greetings, fellow Snurflers!

We have now entered that season during the academic year when many of us are facing great hurdles:  qualifying exams and dissertation defenses.  I will be presenting my research proposal at quals in a few weeks and I wanted to share some of the images from my work with you.

My research on the evolutionary origin and subsequent modifications of facial muscles in mammals involves a lot of comparative morphology:  looking at a wide range of animals (including non-mammals) to piece together a picture of what is old and what is novel, ancestral and derived, conserved and innovative, and what is just plain weird.  I am using techniques and ideas from developmental biology to show the spatiotemporal sequence of how facial muscles grow and differentiate in different embryos, but to also shed light on some key processes behind the question of why muscles grow over the faces of mammals, but not in animals like reptiles.

At the moment, I am working a lot with the embryos and neonates of the Brazilian Short-Tailed Opossum (Monodelphis domestica), a marsupial that is increasingly being used as a model organism in laboratories.  The images here are of young opossums, collected 14 days after birth.  Like all other marsupials, gestation time is short and the babies are born in an extremely underdeveloped state where they are essentially all just forelimbs and a mouth.  Now a few weeks after birth, these little guys are starting to look much more like recognizable animals.

These photographs were taken after the specimens were bleached into a ghostly white.  There are more steps ahead before we can visualize the development of facial muscles.  See what happens next in our following posts!

Image credit: Curious Sengi.

Bunny Surprises

Bunnies are hiding more than just Easter eggs. . . . . . Image credit: Wikimedia Commons.

The ubiquitous presence of rabbits in North America and Europe has percolated this cute, fluffy animal into the Western popular imagination.  Rabbits are carrot-nibbling vegetarians.  They are timid.  And bunnies must be boffing continuously, given their prolific fecundity.

Let’s take a closer look through three vignettes that shed slightly different light on these animals.

Not a bad mom, just a bad day

Rabbits do, in fact, breed like rabbits.  The Common Rabbit (Oryctolagus cuniculus) gives birth to an average of 5 to 6 young after a gestation of about a month.  Though the young are altricial — born with eyes closed, pink, and in need of intensive parental care — the female is ready to mate again a few hours after giving birth.  Under ideal conditions, a female can potentially have anywhere from 5 to 7 litters per year.  However, conditions are rarely ideal.  It is estimated that at least 60% of all O. cuniculus pregnancies are aborted, with the embryos simply resorbing back into the mother’s body (Macmillan Illustrated Animal Encyclopedia 1984; Nowak 1999).

Recently-born rabbits, or kits, peeking out from their fur-lined nest.  Image credit: Ruth : ) via Flickr.

Even under optimal conditions in captivity where there is ready access to nutritious food, water, and nesting material, things do not always go according to plan.  In a study of wild O. cuniculus kept in enclosures, researchers noted that about 13% of all litters experienced neonatal cannibalism, where the mother purposefully killed and consumed her newborns.  (It should be noted that neonatal cannibalism not uncommon amongst mammals.)

The authors of the study concluded that this behavior was most likely triggered by stressful conditions, in this case, placing wild animals into a confined space.  Stress during the time leading up to the birth of the young causes something along the hormonal-neuronal pathway to be disrupted, thus failing to trigger the onset of maternal behavior.  The warning signs were a failure of the mother to construct a proper nest from grasses and especially the lack of nest lining made from the mother’s own belly fur.  Neonatal cannibalism seems to be dependent on specific circumstances.  This behavior destroys an entire litter, but when conditions improve, cannibalistic mothers are perfectly capable of populating the world with their progeny (Gonzalez-Redondo & Zamora-Lozano 2008).

Attack of the “Killer Rabbit”

Back in 1979, the United States was facing another sort of crisis of confidence in its president, Jimmy Carter.  It was a tumultuous time for many people and as the nation looked towards their elected leader for hope, they were hit with a different vision entirely:  the president sitting in a fishing boat on a quiet Georgia lake, flailing an oar at a crazed rabbit swimming towards him (O’Grady 2014).

President v. rabbit, with the President finally gaining the upper hand.  Image credit: Jimmy Carter Library and Museum via WNYC.

It took no time for the public and Carter’s political detractors to latch onto this story of the “killer rabbit”, pointing out that a leader nearly bested by a little bunny had no place handling serious affairs on the world stage (O’Grady 2014).  But let’s step back for a moment and focus on the biology here.  Carter was most likely accosted by a Swamp Rabbit (Sylvilagus aquaticus), which is found inhabiting marshes and wetlands of the southern U.S.  S. aquaticus is particularly adept at swimming and diving, often taking to the water when pursued by predators or traveling to new feeding areas.  This species is amongst the largest of the cottontail genus, robustly-built and “large-headed” (Macmillan Illustrated Animal Encyclopedia 1984).  The rabbit is generally docile, but it is a territorial animal (Nowak 1999) and confrontation between males can result in vicious fights that leave serious wounds (Macmillan Illustrated Animal Encyclopedia 1984).  Though it is highly unlikely the creature was intentionally going after the President, a swimming rabbit making a chance encounter with one of the most powerful people in the world was just too good to resist.

Expectation:  the killer Rabbit of Caerbannog from “Monty Python and the Holy Grail”.  Reality (at best):  a chance encounter between the Commander-in-Chief and a local Swamp Rabbit doing what Swamp Rabbits do, which is swim and maybe feel a little bit territorial.  Image credit: Wikipedia.

Back to blood

“Are carnivorous rabbits possible, anywhere?  No, this is a theoretical absurdity.”  

(Seddon 1972, quoted in Clauss et al. 2016)

How it’s supposed to be. . . .right?  Image credit: via Pexels.

Rabbits are iconic vegetarians.  It had long been assumed that anything other than herbivory was physiologically impossible.  The lack of carnivorous teeth and a digestive system unadapted to processing meat makes this seem obvious (Clauss et al. 2016).  But we did see instances of neonatal cannibalism in our first vignette.

Clauss et al. 2016 report on two domestic dwarf rabbits that were kept in a mixed-species enclosure at a Swiss raptor rehabilitation center.  Over a 9 month period, these two rabbits shared their home with a variety of kestrels, kites, buzzards, and other birds of prey. . . . as well as a shared taste for meat.  While the rabbits were amply provided with fresh vegetarian fare, the raptors were offered whole mice, rats, and day-old chicks.  The rabbits did not neglect their own food, but were drawn to the meaty offering, even chasing birds away from the food.  The authors noted that the rabbits

. . . used a gnawing ingestion style with the extremities of day-old chicks and rodent tails.  When the caretaker brought the daily prey ration for the raptors, the rabbits immediately ran towards the person and followed him even when the dish was placed on an upper perch, where they had to climb a ladder-like staircase (Clauss et al. 2016).

It is like some kind of Easter gathering gone horribly wrong.  These domestic carnivorous rabbits reportedly had neither a favorite prey item nor seemed to suffer any ill-effects from consuming meat.  Image credit: Clauss et al. 2016.

The question is whether this represents some kind of pathological behavior.  An increasing body of observations of presumably exclusive herbivores consuming carcasses and small animals seems to indicate that this is within the realm of natural activity.  If anything, these instances of carnivory were driven by opportunity.  Under usual circumstances, it is unlikely that a rabbit would remain out in the open, gnawing away at a carcass when it was in danger of meeting the same fate from predators.  But in the safe environment of the enclosure (incidentally, the rehabilitating raptors did not pose a threat) the rabbits were at leisure to engage in some casual carnivory (Clauss et al. 2016).

There is so much more to say about rabbits and their relatives than I have time for right now.  But I hope this little trio of information has sparked your interest in these unassuming, yet utterly surprising animals!


Clauss, Marcus, Andreas Lischke, Heike Botha, & Jean-Michel Hatt.  2016.  “Carcass consumption by domestic rabbits (Oryctolagus cuniculus).”  European Journal of Wildlife Research 62:  143 – 145.

González-Redondo, P. & M. Zamora-Lozano.  2008.  “Neonatal cannibalism in cage-bred wild rabbits (Oryctolagus cuniculus).”  Archivos de Medicina Veterinaria 40:  281 – 287.

Macmillan Illustrated Animal Encyclopedia.  1984.  Philip Whitfield, ed.  New York, NY:  Macmillan Publishing Company.

Nowak, Ronald M.  1999.  Walker’s Mammals of the World, Vol. II.  6th edition.  Baltimore, MD:  The Johns Hopkins University Press.

O’Grady, Jim.  “How Jimmy Carter’s Face-Off with a Rabbit Changed the Presidency.”  WNYC .  New York Public Radio, 17 February 2014.  Web.  Accessed 15 April 2017.

Sloths Wearing of the Green

Three-toed sloth festively sporting green fur.  In case the common names get confusing, remember that all sloths have three toes.  The distinguishing number of digits is in the hand.  Image credit:  Azulia via Pixabay.

Sloths are pretty darned slow.  So slow that they seem overtaken by the ever-creeping growth of the rainforest.

There are six living species of sloth distributed across Central and South America and each of these species have individuals observed with striking green fur.  This green comes from algae, primarily Trichophilus welckeri (Suutari et al. 2010).  But it is not just green algae that inhabit sloth fur.  The hairy pelage is a practical ecosystem supporting a community of microbes, fungi, roundworms, beetles, cockroaches, and moths (Suutari et al. 2010).

You might want to think about that the next time you are taken with the impulse to pluck a sloth out of a tree and hug it.

Modern research has shed some interesting light upon the relationship between sloths and the green algae in their fur.  Suutari et al. (2010) undertook an analysis of hair samples taken from all six living sloth species.  Of the 71 total samples, 73% hosted green algae, with Trichophilus being the most frequently found and abundant.  But genetic signatures from rRNA retrieved from the hairs showed a diverse assemblage of eukaryotes most likely acquired from the environment.

Microstructure of three-toed sloth, Bradypus hair.  Note the irregular cracks.  Image taken with scanning electron microscopy (SEM).  Image credit:  Wujek & Cocuzza (1986).

SEM of two-toed sloth, Choloepus hair.  The microstructure of this hair shows longitudinal grooves.  In both the three- and two-toed sloth, these grooves and cracks are home to green algae, cyanobacteria, diatoms, and other microbes (Suutari et al. 2010).  Image credit: Wujek & Cocuzza (1986).

The appearance of green algae was most commonly found in the three-toed sloths (within the genus Bradypus).  But what was even more interesting is that the various strains of Trichophilus algae found on all the different species of Bradypus throughout Central and South America are all closely related to each other.  In fact, the Trichophilus algae found on a given species of Bradypus would be more genetically related to the algae on a geographically distant Bradypus species than with the Trichophilus algae found in the fur of a local two-toed sloth (Choloepus spp.).  This suggests a long history of co-evolution between Bradypus and Trichophilus, one that might be an echo of the divergence between three- and two-toed sloths approximately 20 million years ago (Suutari et al. 2010).

Green-furred two-toed sloth (Choloepus spp.) crossing a road in Costa Rica.  Image credit: Chirriposa Retreats via Vimeo.

It had long been assumed that the presence of green algae was part of a symbiotic relationship where the sloth provided shelter for algal growth and the algae in turn provided some kind of camouflage for sloths as they whiled away in the verdant canopy, protecting them against aerial predators (Pauli et al. 2014).  There are other hypotheses out there as well.  And some of these are a bit “out there.”  It has been proposed that algae provide a nutritional boost for sloths, who are burdened with a low-energy leaf diet.  Someone has suggested that sloths receive nutrients that diffuse into the hairs and absorb into the skin (Suutari et al. 2010).  But that seems a bit silly.

Pauli et al. (2014) proposed a more complex symbiotic relationship based on the observation that three-toed sloths (Bradypus spp.) make regular descents down from the trees to poop on the ground.  Why bother with this dangerous and exhausting journey to do your business?  Clambering down a tree once a week is estimated to use up about 8% of a sloth’s daily energetic budget, in addition to the statistics that more than half of adult sloth mortalities occur as a result of predation events on or near the ground.  The authors of this study put forth that these weekly visits to established latrine sites “sustains an ecosystem in the fur of sloths, which confers cryptic nutritional benefits.”

Are you ready for this?

Remember the moths that also live in sloth fur?  They lay their eggs in sloth poop.  Revisiting these latrine sites provides an opportunity for female moths to lay eggs and for the next generation of moths to colonize the sloth’s fur.  An increase in the moth population also increases the amount of nitrogen, which feeds the growth of algae.  Finally, the sloth consumes this “algae-garden”, which is supposedly highly digestible and rich in fats, as a nutritional supplement to their otherwise poor diet (Pauli et al 2014).

Image credit: Pauli et al. (2014).

While this is certainly a novel idea that could benefit from further investigation, the researchers have yet to provide conclusive evidence for this symbiosis.  While algal cells were found in the stomach of sloths, it is difficult to say if there is enough being consumed to provide significant nutritional benefits.  Likewise, this hypothesis could be supported by behavioral studies showing licking of the fur that would remove algae for consumption.  Also, it does not address the observation that the presence of green algae is common, but not universal, amongst three-toed sloths.

Green sloths remain a mystery.  But in the world of mammals, green is a very rare color to be found in the hair or skin.  So let’s raise our glasses to the sloths, who are so lucky to have this unusual color!

This Bradypus is keepin’ it green, keepin’ it real.  Image credit: Justin Lindsay via Flickr.


Fountain, Emily D. et al.  2017.  “Cophylogenetics and biogeography reveal a coevolved relationship between sloths and their symbiont algae.”  Molecular Phylogenetics and Evolution 110:  73 – 80.

Pauli, Jonathan N. et al. 2014.  “A syndrome of mutualism reinforces the lifestyle of a sloth.”  Proceedings of the Royal Society B 281 (1778):  20133006.

Suutari, Milla et al.  2010.  “Molecular evidence for a diverse green algal community growing in the hair of sloths and a specific association with Trichophilus welckeri (Chlorophyta, Ulvophyceae).”  BMC Evolutionary Biology 10 (1):  86.

Wujek, Daniel E. & Joan M. Cocuzza.  1986.  “Morphology of hair of two- and three-toed sloths (Edentata:  Bradypodidae).”  Revista de Biologia Tropical 34 (2):  243 – 246.

Got My Valentine Right Here


A pair of aardvarks (Orycteropus afar) dozing together under an observational red light at the Philadelphia Zoo.  Aardvarks are sexually monomorphic, making them particularly difficult to sex (Parys 2012); however, the pair seen here are Sunshine (female) and AJ (male)*.  Image credit: Philadelphia Zoo / Curious Sengi.

To be honest, there is not much known about the love-life of aardvarks.

These animals are solitary for most of the year, until the rainy season floods out their haunts in the grasslands and forces them to retreat to higher ground.  This concentration of the population into a smaller area might initiate some aardvark love, as observers have noted male-female pairs “gambolling” and entering burrows together during this time.  However it may work, baby aardvarks appear about seven months later.

Aardvarks dig out sleeping holes with their powerful claws.  These chambers are usually just a little larger than the size of the body and the animals sleep curled up, snout covered by tail and hindfeet (Kingdon 1971).  Squeezing in two aardvarks into a single sleeping hole is a bit tight, but their predilection for snoozing snoot to foot is pretty darn cute!


Image credit: Sebastien Millon via DeviantArt.

* A sad note:  AJ the aardvark recently died at the Philadelphia Zoo in January 2017.  Read about it here.


Kingdon, Jonathan.  1971.  East African Mammals:  An Atlas of Evolution in Africa, Volume I.  London:  Academic Press.

Parys, Astrid et al.  2012.  “Newcomers enrich the European zoo aardvark population.”  Afrotherian Conservation 9:  2 – 5.

James Madison Dissects a Weasel


Illustration of two European mustelids, the Belette (Mustela nivalis) and L’Hermine (Mustela erminea), from Volume 7 of Illustrations de Histoire naturelle générale et particulière avec la description du Roy (1758).  James Madison consulted this work when describing his own locally-caught weasel.  Image source: Wikimedia Commons.

Just a few years before authoring the U.S. Constitution’s Bill of Rights, James Madison (1751 – 1836) was sitting at home in his Virginia estate, dissecting a weasel and writing up his detailed results in a letter to Thomas Jefferson (1743 – 1826).

This letter — dated June 19th, 1786 — is a remarkable one, the sort of enlightened discourse one imagines of such great minds.  It begins with a discussion about the nature of poverty in Europe (described by Jefferson in a previous letter) and the United States, as well as the presumptive role the mode of government had in shaping the existence of the poorer classes.  A little report on the weather and the crops, then Madison expresses “. . . a little itch to gain a smattering in chymistry.  Will you be kind eno’ to pick up some good elementary treatise for me. . .[?]”  There is a brief paragraph on pushing through a state legislative bill for road repair and maintenance.  Then come the weasels.


James Madison, statesman of Virginia, co-author of the “Federalist Papers”, architect of the Constitution and Bill of Rights, 4th President of the United States, dissector of weasels.  Image credit: Gilbert Stuart: The Complete Works.

Madison explains that the body of a female weasel (Mustela frenata) came into his possession and then continues to fill up over two pages (in this four page letter) with detailed descriptions of the animal.  Here is a taste:

Its colour corresponded with the description given by D’Aubenton of the Belette & Roselet or Hermine in its summer dress, excepting only that the belly &c. which in the European animal was white, was in ours of a lightish yellow, save only the part under the lower jaws which was white for about ½ an inch back from the under lip. The little brown spots near the corners of the mouth mentioned by D’Aubenton were peninsular. The tail was of the color of the back &c. all but the end which was black. The ears were extremely thin, had a fold or duplication on the lower part of the conque about 2 lines deep, and at the margin all around were covered with a very fine short hair or fur of the colour nearly of the back. The rest of the ear was in a manner naked, and of a lightish color.

Madison just keeps on going. . . .  and these were not just superficial observations.  The man measured weasel kidneys in three dimensions and counted the number of ridges in the palate.  Whether to wife Dolley’s consternation or approval we may never know, but Madison was digging into the anatomy of small mammals with the same sort of intensity with which he approached national constitutions.


An example of the beast in question:  the Long-Tailed Weasel (Mustela frenata).  Weasels are fierce little carnivores, occasionally taking down prey many times their own size.  Image credit: Evan Jenkins via Flickr.

There is little doubt that Madison was emulating his correspondent and role model Jefferson by drawing up charts comparing a variety of anatomical measurements between his weasel and the European “Belette” and “Hermine.”  These tables of measurements reflect those published by Jefferson the previous year in his Notes on the State of Virginia (1785).  What Madison was doing was comparing the anatomy of his American weasel with European species as described by the natural history authority, Louis Jean Marie Daubenton (1716 – 1800), for the purpose of building up evidence against Old World ideas about biology.  Madison’s specific conclusion from his dissection of the weasel:

The result of the comparison seems to be that notwithstanding the blackness of the end of the tail & whiteness of the feet, which are regarded as characteristics of the Hermine contradistinguishing it from the belette, our weasel cannot be of the former species, and is nothing more than a variety of the latter. This conclusion is the stronger, as the manners of our weasel correspond more nearly with those of the Belette, than with those of the Hermine. And if it be a just conclusion, it may possibly make one exception to Buffon’s position that no animal is common to the two continents that cannot bear the climate where they join; as it certainly contradicts his assertion that of the animals common to the two continents, those of the new are in every instance smaller than those of the old.

In this last statement, Madison is referring to prominent French naturalists such as Daubenton and the Comte de Buffon (1707 – 1788) who claimed that America was only capable of producing puny counterparts to European species.  This notion of degeneracy was summarized by Jefferson in Notes on the State of Virginia:

The opinion advanced by the Count de Buffon is 1. That the animals common to both the old and new world, are smaller in the latter.  2. That those peculiar to the new are on a smaller scale.  3. That those which have been domesticated in both, have degenerated in America: and 4. That on the whole it exhibits fewer species.  And the reason he thinks is, that the heats of America are less. . . . that heat is friendly, and moisture adverse to the production and development of large quadrupeds.

It did not take much imagination to figure out that degeneracy applied not just to animals, but to people as well.  This was a humiliating and detrimental statement against a newly-birthed nation striving to assert its independent identity and ability to thrive in the face of global skepticism.  It was also blatantly contradictory to what Americans observed daily on their farms, in the forests, and in the ranks of their own fellow citizens.  Men like Madison and Jefferson — as well as Benjamin Franklin, John Adams, and Alexander Hamilton — were infuriated by such pretentious Old World assumptions about the New World (Dugatkin 2009), assumptions that were not based on records of observed facts, but upon some kind of arbitrary, feel-good narrative.  No sophisticated argument was necessary to simply show that North American animals are not categorically diminutive compared to European ones.  But it was still important to make sure those data were carefully collected and circulated.  Eventually, the idea of degeneracy lost steam and died out.


Madison’s letter to Jefferson included this rather spectacular table of measurements comparing his weasel (left column) with European species (middle and right columns).  As Mythbuster Adam Savage said:  “Remember kids, the only difference between screwing around and science is writing it down.”  Well, honestly, I cannot imagine Madison screwing around.  Image credit: Library of Congress.

I wonder if it should be remarkable to us in this modern age, to learn that these men who led the American Revolution and the early days of the Republic — many of whom would serve as President of the United States — engaged in what we would recognize as science.  They were not necessarily scientists, though they thought scientifically.  Science also had a broader meaning in the 18th century, a meaning that stood at the foundation of the Enlightenment ideal.  Science was the application of empirical, experimental studies for the betterment of the human condition.  Science was the triumph of reason and Nature’s laws over fanaticism.

Take, for example, wealthy farmers such as Jefferson, Madison, George Washington, and John Adams.  They were all involved in agricultural research of some sort, keeping extensive multi-year records in an effort to develop better compost mixes, meteorological predictions, plant cultivars best suited for a given climate, and methods of crop rotation (Engle 2002; Druckenbrod et al. 2003; “George Washington and Agriculture”).  Of course, increasing crop yields did contribute directly to personal gains in wealth, but it was also about making gains in national wealth.  As gentlemen farmers, these men felt an obligation to be the experimenters because they were in a better position to absorb the costs of failure impossible for smaller subsistence farmers (“George Washington and Agriculture”).  What they learned, they shared in the interest of making the new United States a profitable and self-sustaining continent.  In turn, this made the largely isolationist policy of the Early Republic possible during those vulnerable, fledgling years.

Science had a real impact on the fate of the United States.  Jefferson, Madison, Washington, Adams, and their compatriots understood this.

Science continues to have a real impact on the fate of the United States and the world, but I am much less confident that our elected leadership understands this.

For all the things we may find distasteful, hypocritical, or abhorrent about the 18th century world that produced the Age of Enlightenment, I think we still must admire the dedication to the painstaking business of improving the state of humankind through reason, sympathy, and a better understanding of Nature.  Certainly, science has changed a lot since the days of Madison dissecting a weasel at home in Montpelier.  A lot of research now requires specialized facilities and training only available through higher level university education.  There are increasingly more specialized niche fields with their own language and communities, each one producing more published literature than can possibly be consumed or understood.  But this is no excuse to reject science.  This is no excuse to ignore the thousands upon thousands of scientists reaching out to the public and shouting themselves hoarse over the reality of climate change.

We must strive to be James Madisons and Thomas Jeffersons in our own right.  Let us be driven by intellectual curiosity for the world around us.  Let us be willing to get our hands dirty to study the evidence for ourselves.  Let us share what we have found through thoughtful civil discourse.  And let us not easily dismiss the weasel as insignificant — for even the small and eccentric can hold the key to some big ideas!


Druckenbrod, Daniel L. et al.  2003.  “Late-Eighteenth-Century Precipitation Reconstructions from James Madison’s Montpelier Plantation.”  American Meteorological Society:  57 – 71.

Dugatkin, Lee Alan.  2009.  Mr. Jefferson and the Giant Moose:  Natural History in Early America.  Chicago, IL:  University of Chicago Press.

Engle, Corliss Knapp.  2002.  “John Adams, Farmer and Gardener.”  Arnoldia 61 (4):  9 – 14

George Washington and Agriculture.”  The Digital Encyclopedia of George Washington.  Accessed 14 November 2016.

Jefferson, Thomas.  1786.  Notes on the State of Virginia.  Published in The Portable Thomas Jefferson.  1975.  Merrill D. Peterson, ed.  New York, NY:  Penguin Books.

Jefferson, Thomas, and James Madison. James Madison to Thomas Jefferson, June 19, 1786.  1786. Manuscript/Mixed Material. Retrieved from the Library of Congress.  Accessed 11 November 2016.


Getting Inside “The Elephant’s Head”

Greetings, fellow snurflers!

Pre-quals are coming up this week and as I am preparing a presentation on my proposed doctoral research into the evolutionary origins and specialization of mammalian facial muscles, I wanted to share with you a key text in this field of research.  Boas and Paulli’s two volume work, The Elephant’s Head, is not just scientifically significant, it is also a deeply beautiful illustrated work.


The first volume of The Elephant’s Head was published in 1908, with the second volume following many years later in 1925.  As far as I can tell, this monograph cannot be obtained for love or money. . . . luckily, the Beinecke Rare Book and Manuscript Library at Yale had a copy available for study under the watchful eye of librarians.  The volumes consist of unbound, loose leaves.  The pages are huge, though ironically, not elephant folio-sized.  All of the images in this post are photographs I took while wobbling around on tiptoe, trying to get the whole page into frame without causing too much of a scene!  Image credit: Beinecke Rare Book & Manuscript Library / Curious Sengi.


Schematic drawing showing muscle fiber orientation for the buccinator (cheek) and muscles surrounding the eyes.  Image credit: Beinecke Rare Book & Manuscript Library / Curious Sengi.

The supposed genesis of this masterwork was around the year 1899, with the death of a young Indian elephant from the Copenhagen Zoo.  Two Danish anatomists, Johan Erik Vesti Boas (1855 – 1935) and Simon Paulli (1865 – 1933), seized the opportunity to study the body, especially the head and proboscis.  What Boas and Paulli quickly discovered was that in order to properly understand the anatomy of the elephant’s highly specialized head, it was necessary to engage in a comparative survey of the facial musculature of a wide variety of mammals.  Over the next several years and what I imagine are many dozens of dissections later on specimens provided by the zoo, Boas and Paulli were prepared to publish the first installment of the most comprehensive zoological study of facial musculature ever before or since.

So here’s hoping that pre-quals goes by with the average amount of snot and tears (I am not even asking for the minimum amount), and that we can continue in this tradition of producing beautiful and meticulous comparative anatomy!


Comparative snoot muscle anatomy. From top to bottom: elk, coati, hedgehog, dromedary, and wapiti. (I admit to being a bit confused about the nomenclature here, as my understanding is that the elk and wapiti generally refer to the same animal — any ideas?)  Image credit: Beinecke Rare Book & Manuscript Library / Curious Sengi.

Happy Halloween — Attack of the Taxiderpy!


Sometimes, it really isn’t your fault. You start off looking fabulous, but then time takes its inexorable toll.  Rust never sleeps and you seriously need a nose job.  Pangolin (Manis spp.) Image credit: Yale Peabody Museum / Curious Sengi.


Other times, the best intentions of your preparator just goes a bit awry. . . .  Virginia opossum (Didelphis virginiana).  Image credit: Yale Peabody Museum / Curious Sengi.


Then there are instances of– HOLY CRAP WHAT HAPPENED HERE?!?  Malayan or Sunda Colugo (Cynocephalus variegatus).  Image credit: Yale Peabody Museum / Curious Sengi.

The Mole Hunter, Gillian Godfrey


This mole (Talpa spp.) is delighted you are here!  Image credit:  Cani Animali e Natura.

In celebration of Mole Day, we honor the life and research of Dr. Gillian Godfrey, who is largely remembered for her work on the life history of moles (the furry, digging kind) and writing popular books on the subject.

Gillian was described as “an extremely shy but fiercely dedicated zoologist”, who was drawn to ecology despite the “abominable lectures” given at Oxford University by Professor Charles S. Elton (1900 – 1991).  After the term ended, she contacted Elton about joining his Bureau of Animal Population, but she did so with little expectation that she could have any hand in the scientific work going on there:

Her interview with Elton was awkward.  He told her he didn’t care to have women in the Bureau just yet. She offered to work as a bottle washer and that did the trick.  There wasn’t much future in bottle washing he retorted, so she had better come and do research (Crowcroft 1991).

Attitudes towards women in science in the 1950s was, at best, greeted with amusement or skepticism, but Gillian joined a group investigating vole (Microtus spp.) biology and pursued an ambitious research project on the “factors affecting the survival, movements, and intraspecific relations during early life” in vole populations (do not worry, the moles will come later).


Vole (Microtus spp.)  Image credit: David Chapman via Saga Magazine.

The first step in this project was to induce the voles to nest so she could reliably return to her study subjects and trace their life histories.

With great single-mindedness, and almost no experience with hand tools, she set about mass producing nest boxes in D.K.’s [technician Denys Kempson’s] workshop.  After his initial consternation, not because of the possibility of her injuring herself, but because he feared she might damage his tools, he diplomatically suggested that she work undisturbed in the field store.  For many days the corridor echoed with the sounds of saw and hammer, and Gillian emerged with large numbers of wooden nest boxes with removable lids (Crowcroft 1991).

For all the work and enthusiasm poured into building nest boxes of all kinds of design, the voles were unappreciative of the effort and continued to built their own nests in clandestine locations (Crowcroft 1991).  So Gillian proceeded to comb every square inch of her study site, crawling about on her hands and knees, parting the long tussock grass, finding plenty of old nests, and learning more about the private life of voles than this frustrating exercise initially promised (Crowcroft 1991; Chitty 1996).  But this was no way to gather data for her project.

Then, in an inspired change of tactics brought about by the failure of the voles to use her nest boxes, she set out to trace their movements and find their nests by putting radioactive rings on their legs and finding them with a Geiger-Müller counter.  She was greatly assisted on the technical side by a physicist with amorous ambitions which were fruitless and ill-conceived.  Cobalt 60 wire was obtained. . . . before the Boss got wind of the project.  He was pretty upset by her initiative, but saw that the technique had such great possibilities that she got away with it.  This was the first time small mammals had been tracked in this fashion. . . . I [Crowcroft] still have some mental discomfort when I recall cutting up the wire for Gillian with two pairs of pliers, and rescuing bits that flew off by using the screaming Geiger counter (Crowcroft 1991).


The portable Geiger-counter-on-a-stick used to trace the location of voles through the thick grass.  Image credit: Godfrey 1954.

It was a brilliant innovation, one Gillian claimed was inspired by the use of radioactive materials to track the movements of click beetles (Agriotes spp.) (Godfrey 1954).  By mounting a Geiger counter on the end of a pole, it was possible to sweep large areas of habitat and locate an individual animal (Mellanby 1971).  In writing up her novel methodology, Gillian acknowledged the advantage of this relatively non-invasive technique, since:  “Nearly all available information about small wild animals has been obtained by indirect methods. . . .and it is usually impossible to assess the errors introduced.  Trapping is frequently used in studies on movements but probably affects normal behaviour (Godfrey 1954).”

There were other breakthroughs to be had.  Crowcroft (1991) writes:

I can recall finding Gillian in the vole room, hands streaming with blood and face streaked with tears, bravely pressing on with vole examinations, and explaining with great embarrassment, “Oh, but they bite so hard!”  A few weeks later she was deftly holding them by the loose skin of the back with one hand, palpating the abdomen with the other.

One imagines that this determination and persistence carried Gillian through the tough years doing her doctorate.  While composing her thesis, she was caught in the cross-currents of opposing views held by her examiners.  Forced to write and re-write sections to appease these men who considered each other heretics, Gillian still navigated the conflicting torrents, and emerged triumphant.  She was granted a doctorate by Oxford University in 1953 and was the first woman to complete such a degree in the Bureau of Animal Population (Crowcroft 1991; Chitty 1996).


What the radioactive tracking data look like for a single vole.  For this given research project, Gillian collected 709 recordings of 23 animals.  These maps showed the average distance between farthest points of capture was 29.04 yards (26.6 m), encompassing an area of 235.17 square yards (215.04 square meters).  Data like these provide important information on the life history and distribution of these small mammals.  Image credit: Godfrey 1954.


Moles are incredibly adapted to life digging underground:  reduced, almost useless eyes, ears lacking any external pinnae, and powerful digging forelimbs.  Since moles spend nearly all their lives underground, it had been almost impossible to reliably track their daily movements.  Image credit: Mellanby 1971.

Gillian applied the same radioactive tagging technique to study the movement of moles (Talpa spp.), which are true insectivorans and not rodents like voles.  This method was ideal for tracking these secretive animals.  Instead of ringing the leg, a metal band with a soldered capsule containing radioactive Cobalt 60 was fixed to the mole’s conveniently club-shaped tail, which did not permit the ring to slip off when secured at the base.  The ring could be detected up to 30 cm (1 ft) underground using the Geiger counter.


This drawing demonstrates the mole’s club-shaped tail:  constricted at the base and widening towards the end.  The black rectangle represents the position of the radioactive tracking ring.  The shape of the tail prevented the ring from slipping off.  Image credit: Mellanby 1971.

Even though Gillian’s tracking method became more sophisticated over the years, it was still a hazardous business to work with radioactive materials.  Though she only tracked one animal at a time, she still had to be careful that the animals did not escape from the study site and leave radioactive rings strewn all over the English countryside.  Of course, there was concern that prolonged exposure to Cobalt 60 would have a deleterious effect on the moles.  Despite all these dangers, Gillian discovered a lot about these animals, including their reproductive habits, home range, and propensity towards three bouts of periodic activity over a 24 hour period (Mellanby 1971).  In 1960, Gillian and her husband, Peter Crowcroft, a Tasmanian zoologist and zoo director (Chitty 1996), published The Life of the Mole, which received both academic and popular praise (Kettlewell 1961).


Image credit:  Oxfam.


Image credit:

Unfortunately, Gillian Godfrey’s own trail quickly goes cold.  Like many women of her time, Gillian was largely defined by her husband.  She married Peter Crowcroft in 1952, while they were still students together at Oxford (Lidicker & Pucek 1997).  We learn from an article in the Chicago Tribune that Peter was hired to be director of the Brookfield Zoo in 1968.  At the time, Gillian was researching marsupials at the University of Adelaide, but would soon leave to join Peter in Chicago.  Upon Peter’s death in 1996 at the age of 73, we read in his obituary that Gillian was, in fact, his second wife.  But at the time of publication, she had disappeared from the picture and Peter was survived by another wife, Lisette.


Gillian seems to have retained her maiden name throughout her scientific career, but sometimes it was necessary to remind people to whom she was married.  Image credit: Godfrey 1954.

What happened to Gillian?  The answers are harder to find.  Radioactive tagging is no longer used to track animal movements in the field, so it is quite likely this contributed to her work fading from scientific consciousness.  But it was an ingenious solution to the problem of following shy, elusive animals in way that was least disruptive to their habits.  Were there more ingenious solutions to address new questions that sparked her interest?  I wish that I were able to find more information about Gillian’s later life and career, and that I could provide some kind of conclusion to this story.

So, Gillian, if you are out there, I hope you know that we think you are amazing!


Gillian out the field, listening for radioactive small mammals.  Image credit: Godfrey 1954.


Australian New Zoo Head at Brookfield.”  Chicago Tribune.  7 February 1968:  4.  Chicago Tribune.  Web. Accessed 20 October 2016.

Chitty, Dennis.  1996.  “Do Lemmings Commit Suicide?  Beautiful Hypotheses and Ugly Facts.”  New York, NY:  Oxford University Press.

Crowcroft, Peter. 1991.  Elton’s Ecologists:  A History of the Bureau of Animal Population.  Chicago, IL:  The University of Chicago Press.

Kettlewell, H.B.D.  1961.  “All about the mole.”  New Scientist 9 (217):  107.

Lidicker, W.Z. & Z. Pucek.  1997.  “William Peter Crowcroft (1922 – 1996).”  Acta Theriologica 42 (3):  343 – 349.

Mellanby, Kenneth.  1971.  The Mole.  New York, NY:  Taplinger Publishing Company.