Are female camels capital breeders? Influence of seasons, age, and body condition on reproduction in an extremely arid region

Abstract

Camels can store huge body reserves, they are the only large mammals able to survive in the hottest deserts of the planet, and thus they provide vital resource for millions of peoples. Yet the influence of environmental conditions on reproduction is not fully understood, especially under severe climatic conditions. We assessed the effect of seasons, age, and body reserves on ovarian functioning, pregnancy rate, and fetal traits in Sahraoui dromedaries form south eastern Algeria. Age and body condition were estimated in 322 females slaughtered for food consumption between November 2012 and February 2014. We examined reproductive tract, ovaries (e.g. follicles, ovarian pathologies) and fetal traits. Most females were cyclic (N = 288); analyses revealed an alternate contralateral ovarian functioning, the left ovary being the most active. Pregnancy rate was low (N = 34 pregnant females), and only the left uterine horn carried a single fetus. In both cyclic and pregnant females we found marked seasonal patterns with a reproductive peak in winter, but without cessation of reproduction during the hot and dry summer. Age and body condition positively influenced ovarian functioning, pregnancy rate and gestational age. All these factors displayed complex interactions. Overall, our analyses suggest that although body reserves are important, dromedary camels are not pure capital breeders. Instead, they exhibit a flexible reproductive strategy influenced by age and seasons. We suggest that the marked lateralization of the functioning of both the ovaries and uterus represents an adaptation that limits fecundity.