Current research

giant african pouched rat olfaction

why are pouched rats excellent 'sniffers'?

In January 2017 I started working as a postdoctoral fellow at Cornell with Dr. Alex Ophir. My work here focuses on the olfactory capabilities of the giant pouched rat (Cricteomys ansorgei).
Currently we are asking questions about social scent preferences, search patterns and strategies and what physiological, anatomical, and behavioral traits enable effective olfaction in this species. In addition to behavioral work, with our collaborator Dr. Michael Sheehan (Cornell), we are examining genetic and genomic aspects of olfaction in this species.
So far, we have found that male pouched rats are most likely to scent mark (with urine) in unfamiliar environments, which may advertise to other individuals (Freeman and Ophir, 2018, Journal of Mammalogy).
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Furthermore, we have determined that male pouched rats that are highly masculinized show an enhanced preference for reproductively available females (based on interest in female scent) (Freeman, Sheehan, and Ophir, 2019, Animal Behaviour).

Richardson's ground squirrel Neurobiology

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As part of my dissertation work, I have been exploring the neural mechanisms of communication and social behaviour of Richardson's ground squirrels (Urocitellus richardsonii) under the supervision of Dr. Heather Caldwell (Kent State) and Dr. Jim Hare (U of Manitoba).

Richardson's ground squirrels are a moderately social, colonial rodent native to the prairies. Our study population was located in Winnipeg, Manitoba, at the Assiniboine Park Zoo.

We conducted research which investigated the neural mechanisms of alarm call perception, as well as production and social behaviour. We found that central vasopressin administration altered squirrel behaviour, making males more vigilant and more likely to escape potential predators, as well as changing aggressive behaviors (Freeman, Hare, Anderson and Caldwell, 2018, Behavioral Neuroscience). Regions important for social behavior and communication contain receptors for vasopressin and oxytocin in this species, though the levels are highly variable among individuals (Freeman, Hare, Caldwell, 2019, Journal of Neuroscience Research​).

We are also interested in which brain regions are activated from different types of alarm calls; our preliminary research shows that high threat vocalizations (i.e. chirps) elicit more activation in regions important in the stress response.

I have also worked on a number of glucocorticoid-related projects, including one where we demonstrated partial heritability of the stress response in ground squirrels (Bairos-Novak, Ryan, Freeman, Anderson, Hare, 2016, Current Zoology).

Vasopressin and oxytocin receptors and bat cooperation

Left: Desmodus rotundus brain (whole)
Right: Desmodus rotundus brain (being sliced coronally; shown is the start of the ventral hippocampus)
In collaboration with Dr. Gerry Carter and Dr. Rachel Page at the Smithsonian Tropical Research Institute, I travelled to Panama in 2017 to collect tissue to examine the neural basis of cooperation in bats. Currently we are slicing bat brains prior to localization of oxytocin and vasopressin 1a receptors, which should help us elucidate the evolution of these potential mechanisms in the Phyllostomidae family.

Previous research projects

Infrasonic communication by indian peafowl

For my masters work, I was supervised by Dr. Jim Hare at the University of Manitoba. We recorded peacocks displaying and noted that there seemed to be low frequency components in the train-shaking displays. We then played back these components using a rotary-based subwoofer that was installed in an old Manitoba Hydro van, creating a resonance chamber to propagate the infrasonic signal. 
We determined that both males and females can perceive this infrasound and respond by becoming alert, and walking and/or running. Males responded to infrasonic signals by vocalizing, but did not respond to the 'audible' (i.e. >20Hz) versions of those signals (Freeman and Hare, 2015, Animal Behaviour).

Fear and maternal investment by song sparrows

In 2009, I assisted Aija White (supervised by Dr. Liana Zanette, Western) with her thesis project investigating maternal investment by song sparrows and the perception of fear. We spent nearly all of a glorious summer in the Gulf Islands nest searching, setting up videos to record predation events, mist-netting, and setting up playback units on breeding territories.
The work determined that perceived predator risk reduced offspring investment, perhaps as a way to shift investment to a following year (Zanette, White, Allen, Clinchy, 2011, Science).
Pictured: Song sparrow nestlings, Gulf islands sunset.

landscape ecology of northern flying squirrels

Flying squirrel after release
Radiocollared female flying squirrel
I spent two field seasons working with Dr. Matt Smith (supervised by Dr. Graham Forbes University of New Brunswick) assisting on his dissertation work examining landscape use by northern flying squirrels. We trapped, translocated, radio tagged and released a number of squirrels to determine how they cross different landscapes. The research showed that squirrels strongly preferred forested routes (Smith, Forbes, Betts, 2013, Biological Conservation), and homed best when connectivity within the landscape was high (Smith et al. 2011, Landscape Ecology). 

Other field jobs

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In addition I have worked and volunteered as a bird bander in both Canada and the US.
Left: Olive warbler, banded in Arizona
Right: Saw-whet banding with master bander David Lamble