a polygynous breeding system with only one reproductive male tend to have smaller deme sizes. Interbreeding between small demes is rare due to these factors. Furthermore, alleles fixate more rapidly in smaller demes. Small demes could, therefore, become genetically distinct from each other. Primates, for example, have the second highest speciation rate among mammals, with one speciation event per lineage every 3 million years. However, not all primate species have a high speciation rate; this is reflected in their deme size and social structure. Guenons (Cercopithecus), for example, live together in small polygynous troops and are a quite diverse genus. On the other hand, baboons (Papio) have a much lower speciation rate. Baboons have larger deme sizes because they live in polygynous multi-male troops. These baboon demes are usually allopatric but gene-flow still exists between demes with hybridization being common. Examples Various populations of gorillas can be understood by their geographical separation and have been assessed to determine distinct and disjointed gene pools. The polar bear, Ursus maritimus, is understood to have 19 identifiable demes, even though their circumpolar distribution allows some interchange among the demes. See also Fragmented habitat Population genetics Memetics References Genetics