Detector Dog teams (consisting of a dog and a single handler) undergo a 10-week training course at the CBSA Learning Centre. The handlers are Border Services Officers, and are trained on how to care for, maintain, and train their dogs. They are also trained to understand the "Cone of Scent;" odour particles always disperse in the shape of a cone: more concentrated at the source, and less concentrated farther away. After the initial training, the handler must keep up a training regimen to ensure their dog remains in top form. Only about 1 in 10 dogs who begin the training eventually become detector dogs.