All Clan members are assigned a totem at birth, and boys are marked with that totem's ritual tattoo as part of the ceremony that marks their passage from child to man following their first major hunting kill. People are also believed to possess personality traits similar to those of their totem spirit; Broud, quick-tempered, stubborn and unpredictable like a woolly rhinoceros (his totem spirit) is a prime example. Totems are also responsible for pregnancy; a woman's moon time is believed to be her totem fighting off the presences of marauding male totems; for this reason, women's totems are almost invariably weaker than those of men and women may not associate with men during menstruation. Should the male totem prove stronger, the woman will become pregnant. If the totem is not strong enough by itself, it may ask for the help of one or more other totems, in which case it may be one of the other totems that leaves behind an impregnating essence. It is considered especially lucky for a boy to have the same totem as the mate of his mother. Totems are assigned by "Mog-ur"s, men whose talent is understanding the world of spirits. Each individual Clan has its own "Mog-ur", but one - the one in the clan which Ayla joins - is traditionally recognized as being first among them.