They spent the night kissing, necking, and embracing as lovers. Male giraffes use their necks as weapons in combat, a behaviour known as "necking". In "ductile fracture", extensive plastic deformation (necking) takes place before fracture. In low intensity necking, the combatants rub and lean against each other. Males typically have thicker ossicones that become bald on top due to frequent necking. This figure also shows the dependency of the necking strain at different temperature. Therefore, at higher temperature, necking starts to appear even under lower strain value. As an example, Caltrans specifies a required mode of failure (i.e., "necking of the bar"). The 6.5-08 cartridge was created simply by necking down the .308 Winchester. It was based on necking down the .32-20 Winchester. Necking begins after the ultimate strength is reached. Then the stress will be localized to specific area where the necking appears. The capital consists of a necking or annulet, which is a simple ring. Moreover, value of formula 21 is related to the resistance toward the necking.