Traits can be inherited by offspring if they are genetic. If a physical trait is more frequently observed in some families or breeds than others, it is a sign the trait is genetic and hereditary.
To rule out other causes of the trait, environmental factors (e.g. shared diet, similar or same housing) should be examined and excluded. The next step is to collect family and phenotype data to construct a pedigree tree. This will give an overview of the inheritance pattern.