Publications in refereed journals:

(* = student, + = post-doc)

Bats are not squirrels: revisiting the cost of cooling in hibernating mammals


Haase CG+, Fuller NW+, Hranac CR*, Hayman DTS, Olson SH, Plowright RK, McGuire LP. 2019. Journal of Thermal Biology, 91: 185 - 193.

Hibernation consists of alternating phases of extended periods of torpor (low body temperature, low metabolic rate), and energetically costly periodic arousals to normal body temperature. Arousals consist of multiple phases: warming, euthermia, and cooling. Although cooling to torpid body temperature is an important phase of the torpor-arousal cycle, it is often overlooked in energetic models. When included, cooling cost is assumed to be 67% of warming cost, an assumption originally derived from a single study that measured cooling cost in ground squirrels. We derived a model of cooling cost from first principles and validated the model with empirical energetic measurements. We compared the assumed 67% proportional cooling cost with our model-predicted cooling cost for 53 hibernating mammals. Our results indicate that using 67% of warming cost only adequately represents cooling cost in ground squirrel-sized mammals. Our model allows for the generalization of energetic costs for multiple species using species-specific physiological and morphometric parameters, and for predictions over variable environmental conditions.


First reported case of diphallia in Corynorhinus townsendii

Fuller NW+, Haase CG+, Silas KA, Olson SH, McGuire LP. 2019. Western North American Naturalist. In Press.

We describe the first reported case of diphallia in a Corynorhinus townsendii captured during fall swarming at a hibernaculum in northern Utah, USA. Upon examination, we determined that one phallus was functional, as evidenced by production of urine, while the secondary phallus appeared to be overgrown with skin. A review of the medical literature relevant to diphallia suggests that this is a case of pseudodiphallia with a bifid shaft. We hypothesize that this morphological deformity likely has a low impact on the survival of this individual but may act as a physical barrier to copulation. To our knowledge, this is the first reported case of diphallia in bats.

Non-peer reviewed publications:

Want to be a Bat Hero this Halloween? Don’t Visit the Batcave.

Haase, CG. Live Science. October 29, 2018

Why Bats Are So Good at Gulping Down (Halloween) Prey

Haase, CG. Live Science. October 25, 2017.

Bats are Charged up for Halloween

Olson, SH. The Medium. October 31, 2016.

When a Bat Sees Its Shadow: Winter Length Affects Bat Survival

Haase, CG. National Geographic. April 17, 2018.