Dear MARMAM community,
On behalf of my co-authors, I’m pleased to announce the publication of our
article:
The Sex Life of Harbor Porpoises (Phocoena phocoena): Lateralized and Aerial
Behavior
William Keener, Marc A. Webber, Isidore D. Szczepaniak, Tim M. Markowitz and
Dara N. Orbach. Aquatic Mammals, Vol 44, Issue 6, 2018.
Abstract
The Golden Gate Bridge in San Francisco Bay provides a non-invasive aerial
platform where harbor porpoises (Phocoena phocoena) can be observed mating. We
photographed 144 mating events over an eight-year period (2010 to 2018)
occurring in all seasons. The mating habits of free-ranging male harbor
porpoises are systematically described, a first for any member of the family
Phocoenidae. The males’ rapid sexual approaches toward females were
characterized by high energy and precision timing as males rushed to contact
females surfacing to breathe. Males always attempted to copulate by positioning
their ventral sides on the females’ left side. This extreme laterality in
sexual approach has not been reported for any cetacean. Males approached
females with force and speed that often resulted in male aerial behaviors (69%
of mating attempts). These behaviors, observed exclusively in mating contexts,
included leaps and splashes that counter the species’ reputation for
inconspicuous behavior. Males also displayed their ventrum or penis toward
females without attempting to copulate. The penis was visible in 60% of the 96
mating events for which the ventrum could be observed, with intromission
confirmed in one event. Males always initiated mating and approached lone
females in 62.5% of mating events. Calves accompanied females during 25% of
mating events. Calves were temporarily separated from their mothers by the
approaching males in approximately half of these events. Additional adults were
observed in 12.5% of groups, although no male-male interactions were observed.
Our findings on the unique mating pattern exhibited by male harbor porpoises
validate some predictions made about their behavior based on their reproductive
biology and anatomy. The data support the hypothesis that males compete
primarily by sperm competition and not contest competition.
The full article, is available at https://doi.org/10.1578/AM.44.6.2018.620 and
is open access as part of a special issue of Aquatic Mammals in honor of Bernd
Wursig. To see the video clips of mating behavior, go to the online
supplemental material page:
https://www.aquaticmammalsjournal.org/index.php?option=com_content&view=article&id=10&Itemid=147
https://www.aquaticmammalsjournal.org/index.php?option=com_content&view=article&id=10&Itemid=147
To request a PDF copy, please email me at [email protected]
mailto:[email protected]
Cheers,
Bill Keener
Golden Gate Cetacean Research
Corte Madera, California, USA
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