mate with. In such a case, it becomes more advantageous for a male to remain with a female, rather than seeking out another and risking (a) not finding another female and or (b) not being able to fight off another male from interfering with his offspring by mating with the female or through infanticide. In these situations, male-to-male competition is reduced and female choice is limited. The end result is that the mate choice is more random than in a more dense population, which has a number of effects including limiting dimorphism and sexual selection. With resource availability limited, mating with multiple mates may be harder because the density of individuals is lowered. The habitat cannot sustain multiple mates, so monogamy may be more prevalent. This is because resources may be found more easily for the pair than for the individual. The argument for resource availability has been shown in many species, but in several species, once resource availability increases, monogamy is still apparent. With increased resource availability, males may be offsetting the restriction of their fitness through several means. In instances of social monogamy, males may offset any lowered fitness through extra pair coupling. Extra pair coupling refers to male and females mating with several mates but only raising offspring with one mate. The male may not be related to all of the offspring of his main mate, but some offspring are being raised in other broods by other males and females, thereby offsetting any limitation of monogamy. Males are cuckolds, but because they have other female sexual partners, they cuckold other males and increase their own fitness. Males exhibit parental care habits in order to be an acceptable mate to the female. Any males that do not exhibit parental care would not be accepted as a sexual partner for socially monogamous females in an enforcement pattern. Obligate monogamy Kleiman also offered a second theory. In obligate monogamy, the driving force behind monogamy is a greater need for paternal investment. This theory assumes that without biparental care fitness level of offspring would be greatly reduced. This paternal care may or may not be equal to that of the maternal care. Related to paternal care, some researchers have argued that infanticide is the true cause of monogamy. This theory has not garnered much support, however, critiqued by several authors including Lukas and Clutton-Brock and Dixson. Enforcement Monogamous mating may also