Weasels of each of the three North American species have been successfully kept in captivity. A type of cage satisfactory for keeping the animals in the laboratory is described by Bissonnette and Bailey (1940:761-763). Some of the captives used their teeth to break glass water-containers and to gnaw slivers of wood from the cages. Ingested slivers of wood and bits of broken glass caused the deaths of some of the captives. Weasels kept by me all were of the species _Mustela frenata_. They thrived on a meat diet but I was always careful to give them, every few days, if not each day, some small rodents entire, thinking that the bits of bone and fur ingested might, in some way unknown to me, keep the digestive tract in better condition than would flesh devoid of hair and bone. Three young weasels approximately the size of mice, in the Okefinokee Swamp of Georgia, were obtained by a hunter who, according to Harper (1927:303), raised them by feeding "milk for a few days, and then fresh meat." Litters of young born in captivity have been successfully raised by the mothers (Hamilton, 1933) and success in getting the animals to breed in captivity and to rear their young is recorded by Wright (1948A). He has found, however, that the majority of his captive adult males show no interest in mating when placed with females in heat. He, therefore, uses only selected males and when a female in heat is to be bred, he places one of his responsive males with her one day, another of his responsive males with her the second day and thus alternates a couple of males for three or four days. Even so, slightly fewer than half of the females which were thus bred produced young. A weasel in the white winter coat was used by Audubon and Bachman (1856:177, Quarto edit.) to drive rabbits out of their burrows in the same fashion that ferrets commonly are used. Although these naturalists refer to their animal as an ermine it probably was _Mustela frenata noveboracensis_, the long-tailed weasel. The animal's teeth (probably canines) were blunted and a long cord tied on its neck. With the aid of this weasel 12 rabbits were caught in one morning and more than 50 in four weeks. Enemies