10.5061/DRYAD.93F51
Rotella, Jay J.
Montana State University
Paterson, J. Terrill
Montana State University
Garrott, Robert A.
Montana State University
Data from: Birth dates vary with fixed and dynamic maternal features,
offspring sex, and extreme climatic events in a high-latitude marine
mammal
Dryad
dataset
2017
Leptonychotes weddellii
maternal effects
birth timing
birth dates
Population ecology
Weddell seals
2017-01-06T00:00:00Z
2017-01-06T00:00:00Z
en
https://doi.org/10.1002/ece3.1985
322494 bytes
1
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Reproductive synchrony tends to be widespread in diverse species of plants
and animals, especially at higher latitudes. However, for long-lived
mammals, birth dates for different individuals can vary by weeks within a
population. A mother's birth timing can reveal useful information
about her reproductive abilities and have important implications for the
characteristics and survival of her offspring. Despite this, our current
knowledge of factors associated with variation in birth dates is modest.
We used long-term data for known-age Weddell seals in Antarctica and a
Bayesian hierarchical modeling approach to study how birth dates varied
with fixed and temporally varying features of mothers, whether sex
allocation varied with birth timing, and annual variation in birth dates.
Based on birth dates for 4465 pups born to 1117 mothers aged 4–31, we
found that diverse features of mothers were associated with variation in
birth dates. Maternal identity was the most important among these. Unlike
most studies, which have reported that birth dates occur earlier as
mothers age, we found that birth dates progressively occurred earlier in
the year in the early part of a mother's reproductive life, reached a
minimum at age 16, and then occurred later at later ages. Birth dates were
positively related to a mother's age at primiparity and recent
reproductive effort. The earliest birth dates were for pups born to
prime-age mothers who did not reproduce in the previous year but began
reproduction early in life, suggesting that females in the best condition
gave birth earlier than others. If so, our finding that male pups tended
to be born earlier than females provides support for the Trivers–Willard
sex-allocation model. Average birth dates were quite consistent across
years, except for 2 years that had notable delays and occurred during the
period when massive icebergs were present and disrupted the ecosystem.
WESE_birthscsv file containing data on pup birth dates, pup sex, year of
birth, and attributes of mothers for Weddell seals in Erebus Bay,
Antarctica for 4.465 pups in 28 different years during 1993 through 2014.
Antarctica