Definition of "interbirth"

Differences in caloric intake by adult females and immatures could be due to the proposed larger cost of reproduction and growth (e.g., later age at weaning, longer interbirth interval and age to sexual maturity) for western gorillas than mountain gorillas, since they inhabit a more seasonal and unpredictable environment [79, 80 ].

2015 July 9, “The Influence of Seasonal Frugivory on Nutrient and Energy Intake in Wild Western Gorillas”, in PLOS ONE‎