Dragons like to face the heat

At long last, my former MSc student, Ian Black’s first paper has been published!  (Citation below)  Ian graduated last year and moved to Ottawa, but has been maintaining contact and working with me to write his work up (so far, we have a book chapter in review and a second manuscript being edited now).

To many that keep lizards as pets, the results of this study might not be so surprising, as articulated by this meme:


From a scientific perspective, however, these results might not have been predicted.  So, what did we show? In a nutshell, we demonstrated that bearded dragons prefer to keep their heads facing toward the heat when given a choice.

To thermoregulatory biologists, this is intriguing.  Why? It is often stated in the herpetology literature that lizards are either heliothermic (i.e. they bask in the sun) or thigmothermic (i.e. they warm up via contact with the substrate), and an implicit corollary is that if a species is known to be heliothermic, it cannot respond to contact based thermal cues (i.e. they cannot sense heat via the skin).  Thus one might not expect them to orient toward or away from this kind of heat source or thermal gradient if they are heliothermic/baskers.

We conducted this study by creating an artificial thermal gradient to allow the lizards the chance to move and select different temperatures throughout the day.

Banner in gradient

Thermal image of a bearded dragon in a temperature gradient (~15C on left, ~42C on right) orienting toward the warm end.

Our paper clearly demonstrates that bearded dragons are very capable of orienting their body along a gradient of temperature, and thus are quite thermally “aware” of the environment around them.  We also demonstrate that both adults and neonates show this behaviour.  Finally, as the lizards choose warmer temperatures later in the day (i.e. move up the gradient), they orient less and less toward the heat, suggesting that they are capable of using their orientation to keep their heads from getting too warm.  Therefore, orientation behaviour is used to fine-tune their thermoregulatory control.  This is analogous to how Galapagos marine iguanas use sky-pointing orientation to maximise solar absorption int he early morning and maximise convective cooling later in the day to prevent overheating (Bartholomew, 1966. Copeia. p 241-250).


Please find links to the study below and consider sharing our findings.

Citation and Links

Black, IRG and Tattersall, GJ. 2017.  Thermoregulatory behavior and orientation preference in bearded dragons.  Journal of Thermal Biology. 69: 171-177. doi:doi:​10.​1016/​j.​jtherbio.​2017.​07.​009

For a limited time (until Sept 13, 2017) the paper is available for free for anyone that does not have a subscription here:


but I will provide permanent links to the pre-print version: Post Review Version or from the Brock University Respository.


Lab trip to Canadian Centre for Inland Waters

Hats off to Environment Canada, the Department of Fisheries and Oceans, and the Canadian Coast Guard for putting on a great open house today at the Canadian Centre for Inland Waters (CCIW)!  Most of my lab (see picture below) agreed to a “lab outing” to the CCIW.  I had always wanted to see what research occurs at CCIW, which is a building nestled directly under the Burlington Skyway in southern Ontario:


With the yoke of information control (http://www.macleans.ca/news/canada/when-science-goes-silent/) lifted following the election of a new government in 2015 (http://www.macleans.ca/society/unmuzzled-government-scientists-ready-to-discuss-a-decade-of-work/), it was amazing to see the enthusiasm in the faces of the scientists working hard to assess environmental impacts of human influences on wildlife, plants, and the ecosystems around us.  Why these scientists were ever bureaucratically muzzled is beyond me.

Here we are looking pleased with ourselves:


Most of the lab in attendance.  From Left to Right: Justin Bridgeman, Nicholas Skakich, Glenn Tattersall, Curtis Abney, and Philip Bartel.  Susan Wang not in photo as she was still having conversations with researchers inside the building.

We even receive visitors badges that reminded me of a strange 1980s sci-fi show:


On the trip home, we even were stopped by the lift bridge, something I usually avoid when driving the QEW:


All told, I was extremely impressed with the open house put on by CCIW and wish to thank them for opening their doors to the public.  Keep up the good work!

Good news in the lab

A couple of significant events occurred in the past couple of weeks in the lab, and I wanted to note them here.

My MSc student, Curtis Abney found out he is a recipient of an Ontario Graduate Scholarship for his research on the thermal biology of garter snakes.  Congratulations, Curtis!

My MSc student, Justin Bridgeman, who is busy attending conferences this summer, received a travel support fellowship to attend the Fisheries Society of the British Isles annual meeting this July!  Congratulations, Justin!


Chimney Swifts in Infrared

Last month, Canadian Nuclear Laboratories invited a number of researchers to witness the nightly roosting of chimney swifts in one of their ventilation stacks!  They were kind enough to allow me to film using my thermal camera the gathering of over 1000 birds at ~8:45pm one evening.  Now, if only I can find the time to help with writing code to help them count the birds entering the chimney!  Here is a brief video and a link to CNL’s facebook site:

A successful defence for Susan Wang!

Congratulations to Susan Wang, MSc student working in my lab and co-supervised with Dr. Janet Koprivnikar (Ryerson University) for successfully defending her thesis on:

“Behavioural Thermoregulation and Energetics in Two Intermediate Hosts of Trematode Parasites”

Thank you for all members of the examining committee for their hard work and interesting defence discussions:

External Examiner: Dr. Carl Lowenberger, Simon Fraser University

Committee Members: Dr. Gaynor Spencer, Dr. Robert Carlone, Dr. Dorina Szuroczki


Two proud supervisors (Koprivnikar, middle, Tattersall, right) and a new MSc student (Susan Wang, left)

Her time in the lab was far too short, but we are proud of her accomplishments and for her hard work on an interesting project.  Because of Susan, I can safely say that we can readily do interdisciplinary research!  Ecological physiology of disease and host:parasite interactions is a fun topic and I’m glad to have had this project taking place in my lab and grateful for Janet Koprivnikar for funding, intellectual, and logistic support, collaboration, and supervision at every step.

Rattlesnake Hibernation Research

Brock University’s Brock News has written up a great piece on Anne Yagi’s (an MSc student in my lab) research.  Anne has worked for the Ministry of Natural Resources for a number of years and joined my lab to pursue questions into the overwintering physiology of snakes.  The article below covers the Conservation Physiological approach she has been taking to understand neonatal rattlesnakes in a sensitive population.  Hopefully we’ll be publishing on this soon.  Congratulations Anne!


Slithering reproductive frenzy in Narcisse, Manitoba

Following the CSZ meeting, a very kind graduate student from University of Winnipeg, Ana Breit, agreed to drive Justin and myself up to Narcisse, Manitoba on the last afternoon of the meeting.  I brought the thermal camera with me, so I could document the spring emergence of garter snakes, and the writhing reproductive orgy that is customary at this field amazing site.

Here are some sample images in visual, thermal and thermal video:




Many thanks to the people at Nature north for maintaining this site: http://www.naturenorth.com/spring/creature/garter/Narcisse_Snake_Dens.html

Canadian Society of Zoologists – Winnipeg

My student, Justin Bridgeman and myself were the representatives from my lab this year.  Unfortunately, I forgot to take photos of him speaking or of me defending my student, Katlyn Dundas’s poster.

For posterity, though, here are the clips from the CSZ program book:


Winnipeg was a great host city and the meeting was excellent.  Always good to catch up with fellow Canadian scientists.

Sabbatical rewards

I just found out that the CNRS (Centre Nationnal de la Recherche Scientifique) did a write-up about work conducted during my 3 month sabbatical at the Université de Lyon with very hospitable colleagues, Dr. Löic Teulier, Dr. Damien Roussel, and Dr. Yann Voituron:


How I miss those guys.

They let me camp out in their lab for 3 months (Sept 2015-December 2015), helped me with renting a place in Lyon, and generally introduced me to the French attitude and ethic and their love of cheese and fine wine.



Fly science

At long last, years of hard work in the field of Drosophila research has met with the fruition of this publication…maybe one day I will blog about the challenges of associated with this field of research.  Now is not the time, but suffice to say, I will say this….if a paper on fruit fly phenotype is published and nothing about the husbandry, nutrition, and rearing conditions are provided, the research should be taken with huge grain of salt.  Context is everything.



Effect sizes of the influence of diet on developmental, behavioural, and physiological parameters

Comparison Phenotype Hedge’s g (± 95% CI) r Significant
Larval wet mass Morphology 32.66 ± 10.16 0.99 Yes
Larval dry mass Morphology 10.60 ± 3.40 0.98 Yes
Larval width Morphology 3.53 ± 0.63 0.87 Yes
Adult wing length Morphology 1.30 ± 0.48 0.55 Yes
Larva Emergence Fecundity 0.80 ± 0.64 0.36 Yes
Pupa Emergence Development 2.09 ± 0.99 0.70 Yes
Adult survivorship Lifespan 0.70 ± 0.13 0.32 Yes
Larva Thermotaxis Sensory 0.80 ± 0.64 0.36 Yes
Adult Thermotaxis Sensory 0.38 ± 0.66 0.18 No
Larval Thermal Retreat Neuromuscular 0.73 ± 0.39 0.34 Yes
Adult Geotaxis Neuromuscular 2.49 ± 1.01 0.77 Yes
Muscle Basal Tonus Neuromuscular 2.51 ± 1.17 0.77 Yes
Muscle Maximum Neuromuscular 0.23 ± 0.88 0.11 No
Learning Index Neurological 0.34 ± 0.88 0.16 No



Survivorship Curves depend on the type of diet