Cowan with pack outfit c. 1929
Harper Ranch, Kamloops, 1929
Cowan’s job was to locate the smaller mammalian hosts for the first two feedings of the Rocky Mountain tick and understand a little more about the different species’ roles as vectors. To do his research he had to trap the animals and extract the ticks. In the course of his Kamloops research, he trapped most of the grassland rodents and prepared specimens from them. This was his first introduction to those species close at hand, and with the aid of these pioneer entomologists, the exercise gave him a classic introduction to grassland ecology.
Cowan started the job and his first journal entries on May 23 at Peterson Creek, which flows north through Kamloops into the Thompson. Temperatures were already reaching 96°F in the treeless grasslands, but Cowan scarcely paused. In his first 24 hours, he caught two dozen Yellow-bellied Marmots (commonly called “groundhogs” in those days).
Marmota flaviventris avara
This marmot inhabits the hotter, more arid parts of the province, where it is most abundant in regions providing an abundance of broken rock, low cliffs, or stone piles. Along the edge of the grasslands it invades the forest edge where suitable rocky den sites occur… This species is one of the favoured hosts of the tick Dermacentor andersoni, the transmitter of Rocky Mountain spotted fever and the cause of the paralysis in man and domestic animals.23
It was the Yellow-bellied Marmot that was to be the subject of Cowan’s first published article in 1929.24 He worked from May until September, and while he was doing his tick research he also put together, at the behest of Kenneth Racey, a guide to the mammals of Kamloops. His unpublished manuscript of that name had a list of the 28 species he saw or trapped that summer, an identification key he worked out and a picture of 11 prepared specimens of small mammals. His photograph captures the small mammal diversity in just one small region around Kamloops. In a later piece for the popular magazine Canadian Geographic, he wrote: “From one barren-looking plot of land in the woods near Kamloops, I set out mousetraps on an area of 100 square yards and took thirty animals of eight different species. Nor was this unusual25.” From the larger marmots and weasels to the tiny Wandering Shrew, you can see the diversity in pelts, coloration, length of tails, whiskers, claws and body shape, all adapted to different niches of the prairie – all of which Cowan explored.
23 Cowan and Guiguet. Mammals of BC, 119.
24 Ian McTaggart Cowan, “Note on Yellow-bellied Marmot,” The Murrelet 10 (1929): 64.
25 Cowan, “Small Mammals of the Western Mountains,” Canadian Geographical Journal 47, no. 4 (1953): 131.