The action of dicoumarol on laboratory and wild rats, and its effect on feeding behaviour

The behaviour of wild rats towards an unfamiliar food presents problems of both practical and theoretical interest (Chitty, 1950; Shorten, 1950; Thompson, 1948). When first eaten the food is often taken in very small amounts; if poison is present its effects soon make the rats stop feeding, and if they recover the rats are often found to bebait-shy; that is, they refuse the bait entirely (Rzoska, 1950). As far as rat control is concerned prebaiting with harmless food can overcome this difficulty by inducing rats to feed rapidly on the bait when poison is eventually added (see Barnett, 1948, for a review); and if there are even then a few bait-shy survivors they may be disposed of by a second prebaiting and poisoning with different materials. In large-scale practice, however, this elaborate programme presents considerable difficulties for organizations such as local health authorities, and they are often unable to adhere to it.