F.M.Brock 1957 Interspecific Reactions 2 Aug 4 A.R.L. Barrow, Northern Alaska started chasing the Micratus about the aquarium and on several occasions succeeded on climbing on the Micratus and attempting to copulate. This chase was allowed to go on for about five minutes during which time the Lemmus made about six attempts to copulate with the Micratus. They were then separated. A second observation a placing the same two individuals together resulted in about six more attempts at copulation in three minutes. Rest of the time spent eating and general exploration of aquarium. All some time spent Lemmus chasing Micratus about aquarium. No outward attempts of a fight were noticed.