The West Highland Terrier, descended from working terriers, has a lot of energy, tenacity, and aggression towards its prey, which was originally the fox and other, smaller animals such as squirrels. They need regular exercise, although their size makes them good apartment pets. Many of these dogs have skin allergies, and their personality is more excitable than even some other terriers. They are alert and consider themselves guard dogs, although their size prevents them from providing any real intimidation. They are independent thinkers with no small amount of self-esteem, and must be trained firmly from an early age. If not raised with other cats and dogs from an early age, they may be aggressive towards such animals later in life. Like all dogs, the Westie responds better to love and gentleness than to cruelty. As with most terriers, harsh training methods are often met only with stubbornness.