Further selection occurs due to the birth interval for a single female averaging 2-2.5 years.

Male fitness would benefit from inseminating other females during a birth interval.

Together with a long lactation period, orangutans also have a long birth interval.

Other factors include shorter birth intervals and possibly a lower likelihood of using reliable contraception.

There is some evidence that length of birth interval has a bearing upon child morbidity.

Among other things, frequent births and short birth intervals may obviously also induce some physical hazards for mothers, however, the effect is not well documented.

Obviously, the effective use of contraception precludes short birth intervals.

Even at such a slow birth interval of a millennium, there should be billions of you by now.

The birth interval is seven and a half months.

The birth interval for the white rhino is between 2 and 3 years.