| Obligate parasites have an absolute requirement for a host, whereas facultative parasites can live and reproduce in the absence of a host. |
| It is useful to reiterate that the canids mentioned above also tend toward minimal sexual dimorphism and facultative monogamy. |
| Other parasites will feed on any host available and are called facultative parasites. |
| I have seen this particularly in those cases where facultative divergence also was greater than usual. |
| Of further interest, these canids also tend toward facultative monogamy and toward minimal sexual dimorphism. |
| The functional significance of facultative sibling aggression is likely to depend on the magnitude of competitive asymmetry between siblings. |
