Data from: Dispersal-induced social stress prolongs gestation in wild meerkats

In the majority of mammals, gestation length is relatively consistent and seldom varies by more than 3%. In a few species, females can adjust gestation length by delaying the development of the embryo after implantation. Delays in embryonic development allow females to defer the rising energetic costs of gestation when conditions are unfavourable, reducing the risk of embryo loss. Dispersal in mammals that breed cooperatively is a period when food intake is likely to be suppressed and stress levels are likely to be high. Here we show that pregnant dispersing meerkats (Suricata suricatta), which have been aggressively evicted from their natal group and experience weight loss and extended periods of social stress, prolong their gestation by means of delayed embryonic development. Repeated ultrasound scans of wild, unanaesthetised females throughout their pregnancies showed that pregnancies of dispersers were on average 6.3% longer and more variable in length (52-65 days) than those of residents (54-56 days). The variation in dispersers shows that, unlike most mammals, meerkats can adapt to stress by adjusting their pregnancy length by up to 25%. By doing so, they potentially rearrange the costs of gestation during adverse conditions of dispersal and enhance offspring survival.Funding provided by: Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen ForschungCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100001711Award Number: CR32I3_159743Funding provided by: European Research CouncilCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100000781Award Number: 294494Funding provided by: Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen ForschungCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100001711Award Number: 31003A_182286Funding provided by: European Research CouncilCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100000781Award Number: 74280