Translocation of individuals among populations may be costly, especially for large animals, and carries the risks of injury, disease transmission and behavioural disruption when individuals are released. For example, introduced male lions regularly kill cubs. Further, sexually mature males of many species may kill intruders. The cost of translocations can be reduced by artificial insemination for species where this technique has been perfected. The same care to avoid outbreeding depression, discussed previously, must be exercised in planning translocations.