Generating interest in your science and writing…

Scientists receive pressures from every angle to perform and justify their existence (parents, deans, students, bureaucrats, politicians, you name it..).  One reason for re-vamping my lab website was to keep a chronicle of lab activities as well as provide a more digestible version of our science to the public.  Since our work is sometimes highlighted by science writers and reporters, I had always assumed it was the scientists who had a tough time getting recognised.  Then I read the blog of a Science Writer, Diane Crow, who had contacted me a few months ago, interviewed me about our work on tegus.  She writes about how she tried to pitch her writing to news-outlets.  Sounds similar to a scientist’s challenge to get their work published.


For anyone interested in science writing and the challenges inherent to it, check out Diane’s blog:

She gives an excellent and frank account of how a science writer has to make what scientists write interesting and friendly to readers.  Sadly, in the case of the tegu story,  this was a pitch that did not work, but that is one of the reasons why I wanted to post a link to her blog!  We appreciate your work!

Here’s to you Diane!   Keep up the good work and engagement on science!


Hibernation and Thermoregulation Research

I just came back from the International Hibernation Symposium (15th!) from Las Vegas and saw this article about one of our participants.  This is great to read, and helps explain why so many of us are passionate about understanding thermoregulation and hibernation.  Some work is biomedically inspired, some is evolutionarily inspired.  Anyhow, here is a nice article about Dr. Domenico Tupone, one of our colleagues and participants:

Thanks for Dr. Matteo Cerri for sharing this link.

Burning love for our science?

I just found out that an image from our published research has been selected by NSERC’s “Science Exposed” contest.  This photo is an actual research figure but also a captivating depiction of a novel discovery: namely endothermy in a lizard.


Here is the photo.

The link to vote is here:

We would all appreciate your vote.  I know some of the other pictures are stunning landscapes and digitally rendered fluorescent images, but our lizard image is the genuine article.

For more information on the science article, please see:

Tattersall, GJ, Leite, CAC, Sanders, CE, Cadena, V, Andrade, DV, Abe, AS, and Milsom WK. 2016. Seasonal reproductive endothermy in tegu lizards. Science Advances. 2: e1500951.


Hornbills and Toucans and Beaks…

Avian bills are fascinating structures, having evolved a 465px-birdbeaksa-svgmyriad of forms and functions, as depicted in the montage on the right from:

Today a new publication on this subject has been published in PLoS One, highlighting the multi-tasking capacity of form and function.  You can find it here and blogged about here.

The authors make the major point that hornbills use their bills like toucans do (as radiators of body heat, showing evidence of greater relative blood flow recruitment at warmer temperatures), but that their calculations suggest that the per area rate of heat exchange in the hornbills is less than the toucans.

This is a nice addition to the recent work done by a number of us in the field (see references below, e.g. Symonds and Tattersall, 2010), emphasizing that bills are not the dead, static structures that many assume they are.

One main point the authors note (they base their comparison mainly vs. toucans from our 2009 paper) is that the bills of hornbills are not as effective as dissipators of heat compared to the toucan and quite likely for multiple reasons: 1) the hornbills’ bill is thicker, so is a heavier barrier to heat exchange, likely because the hornbills use their bills as digging implements and must be more robust, and 2) toucans “switch on” their blood flow at lower temperatures than hornbills, and the lower the air temperature, the greater the driving force for heat loss, and 3) the hornbill bill is relatively smaller than the toucans.  The reason for the hornbill vs. toucan comparison is because the two lineages have long been viewed as old world vs. new world convergences (although that is really an oversimplification).

One point I’d like to emphasize that is often missed in the popular press.  These large billed birds are not unique in their bills’ thermal radiator function, since many other birds exhibit similar capacities to modify blood flow to their bills (geese, ducks, sparrows to name a few).  They are, however, striking in how large their bills are, which is why they garner such attention.

Here is a photograph of a hornbill (what mother could not love that face?):

Glenn_pic 2.jpg

Photo: Courtesy Dr. Andrew McKechnie



Figure from van de Ven (2016), showing the obvious blood vessels under the surface of the bill.

Some technobabble about how the measurements are made:

Like myself, these researchers used thermal imaging to obtain their results (see their paper for images and thermal videos), which means that heat exchange is an estimation of events and is done under sampling assumptions.  I’ve been working on calculations to make things easier for myself and colleagues (see below for R package), and came across a couple of things.  Firstly, some of the assumptions van de Ven et al (2016) used are different than the ones we made (Tattersall et al 2009).  We assumed higher wind speeds (5 m/s) in our modelling, which I think are a little on the high side of reality.  van de Ven et al (2016) on the other hand, assumed a wind speed of zero and therefore incorporated only free convection estimates.  Gates (2003 – Biophysical Ecology) advises that forced convection is the more realistic scenario for heat exchange in animals since wind speeds are rarely exactly zero, and suggests values between 0.5 and 1 m/s.  This means that van de Ven’s estimates of convective heat will be underestimates, while our toucan data are over-estimates.   Anyhow, the good news is that van de Den realized this when making comparisons to our previous work and made comparisons using free convective heat exchange (while politely not criticizing us for our over-zealous wind speeds).  The take home message though is that their published values for both species are on the low side, while our published values are more for what a flying bird might experience.

For anyone interested in using their thermal images for similar analyses, I have create a package in R called “Thermimage” to help in the calculations.

See for the package itself and for some sample scripts.


Gates, DM 2003. Biophysical Ecology.  Dover Publications, Mineola, NY, 611 pp.

Symonds M.R.E., Tattersall G.J. 2010 Geographical variation in bill size across bird species provides evidence for Allen’s rule. American Naturalist 176, 188-197. (doi:10.1086/653666).

Tattersall G.J., Andrade D.V., Abe A.S. 2009 Heat exchange from the toucan bill reveals a controllable vascular thermal radiator. Science 325, 468-470. (doi:10.1126/science.1175553).

van de Ven T.M.F.N., Martin R.O., Vink T.J.F., McKechnie A.E., Cunningham S.J. 2016 Regulation of Heat Exchange across the Hornbill Beak: Functional Similarities with Toucans? Plos One 11, e0154768. (doi:10.1371/journal.pone.0154768).

Additional sources

Greenberg R., Danner R.M. 2012 The Influence of the California marine layer on bill size in a generalist songbird. Evolution 66, 3825-3835. (doi:Doi 10.1111/J.1558-5646.2012.01726.X).

Greenberg R., Danner R., Olsen B., Luther D. 2012 High summer temperature explains bill size variation in salt marsh sparrows. Ecography 35, 146-152. (doi:Doi 10.1111/J.1600-0587.2011.07002.X).

Greenberg R., Cadena V., Danner R.M., Tattersall G.J. 2012 Heat loss may explain bill size differences between birds occupying different habitats. Plos One 7. (doi:ARTN e40933 DOI 10.1371/journal.pone.0040933).

Hughes A.L. 2014 Evolution of bill size in relation to body size in toucans and hornbills (Aves: Piciformes and Bucerotiformes). Zoologia-Curitiba 31, 256-263.

McNab B.K. 2001 Energetics of toucans, a barbet, and a hornbill: Implications for avian frugivory. Auk 118, 916-933.

Seki Y., Bodde S.G., Meyers M.A. 2010 Toucan and hornbill beaks: A comparative study. Acta Biomater 6, 331-343.