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Behavior and body mass changes of a mother and calf Pacific walrus ( Odobenus rosmarus divergens ) during the suckling period
Author(s) -
Kastelein Ronald A.,
van den Belt Ivanka,
Jennings Nancy,
de Kruijf Richard
Publication year - 2014
Publication title -
zoo biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.5
H-Index - 54
eISSN - 1098-2361
pISSN - 0733-3188
DOI - 10.1002/zoo.21189
Subject(s) - biology , zoology , period (music) , gestation , pregnancy , physics , acoustics , genetics
The behavior of a 13‐year‐old female Pacific walrus and her first calf is described during the first 7 months of the 19‐month suckling period. The calf vocalized before 62% of suckling sessions. The mother immediately responded after 84% of vocalizations; after 44% she allowed a suckling session. The number of suckling sessions per 24‐h period decreased from on average nine in the second week after birth to two by the thirteenth week. Thereafter, the number of suckling sessions fluctuated between 3 and 5/day. The average suckling session duration increased from 4 min/day to around 17 min/day. The average effective suckling time per session increased from on average 2 to 10 min. The number of breaks decreased during the study period from around 40 to 20 per session. The mother spent on average 47% of her time resting, the calf 44%. The remaining time was spent in locomotion, and suckling, playing, investigating, and looking. Mother and calf spent on average 51% of time indoors. The mother spent 43% of her time in the water, the calf 39%. The calf's body mass at birth was 55 kg; it increased to 178 kg at 27 weeks. The mother did not eat for the first 5 days after delivery, and she ate less than usual during the next 6 days. The mother's mass eventually stabilized at 1024 kg (>before gestation). The calf was not given formula and was weaned onto fish. This is the first detailed description of a captive Pacific walrus's suckling period. It could benefit the husbandry of future captive‐born walruses, and may elucidate the behavior of wild walruses during suckling. Zoo Biol. 34:9–19, 2015. © 2014 Wiley Periodicals Inc.