Population Ecology

, Volume 59, Issue 1, pp 45–54 | Cite as

Season of birth affects juvenile survival of giraffe

  • Derek Edward LeeEmail author
  • Monica Louise Bond
  • Douglas Thomas Bolger
Original article


Variation in timing of reproduction and subsequent juvenile survival often plays an important role in population dynamics of temperate and boreal ungulates. Tropical ungulates often give birth year round, but survival effects of birth season for tropical ungulate species are unknown. We used a population of giraffe in the Tarangire Ecosystem of northern Tanzania, East Africa to determine whether calf survival varied by season of birth. Variation in juvenile survival according to season of birth was significant, with calves born during the dry season experiencing the highest survival probability. Phenological match may confer a juvenile survival advantage to offspring born during the dry season from greater accumulated maternal energy reserves in mothers who conceive in the long rainy season, high-protein browse in the late dry-early short rainy seasons supplementing maternal and calf resources, reduced predation due to decreased stalking cover, or some combination of these. Asynchrony is believed to be the ancestral state of all ungulates, and this investigation has illustrated how seasonal variation in vegetation can affect juvenile survival and may play a role in the evolution of synchronous births.


Giraffe Juvenile survival Match-mismatch Population dynamics Reproduction Reproductive timing 



This research was carried out with permission from the Tanzania Commission for Science and Technology (COSTECH), Tanzania National Parks (TANAPA), the Tanzania Wildlife Research Institute (TAWIRI), African Wildlife Foundation, Manyara Ranch Conservancy, and the villages of Selela, Lolkisale, and Emboret, under COSTECH permits 2011-106-NA-90-172, 2012-175-ER-90-172, and 2013-103-ER-90-172. We are extremely grateful to J. Keyyu, V. Kakenge, A. Mwakatobe, and K. Oola at TAWIRI; F. Olekashe at MRC, J. Salehe at African Wildlife Foundation, and I. Lejora, D. Njau, S. Quolli from TANAPA. Financial support was provided by Dartmouth College Graduate Studies, Fulbright U.S. Scholar Program, Sacramento Zoo, Safari West, Columbus Zoo, Cincinnati Zoo, Tulsa Zoo, Dartmouth College Cramer Fund, and the Explorer’s Club.


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Copyright information

© The Society of Population Ecology and Springer Japan 2017

Authors and Affiliations

  1. 1.Department of Biological SciencesDartmouth CollegeHanoverUSA
  2. 2.Wild Nature InstituteHanoverUSA
  3. 3.Environmental Studies ProgramDartmouth CollegeHanoverUSA

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