Caring for Selected Otter Species (Asian small-clawed, Cape ...

L. canadensis: These otters are seasonal breeders. Females mature reproductively as early as 12-15
months (rare reports of successful breeding at this age) to two years of age (typical). They are believed to be
induced ovulators, and experience delayed implantation (Chanin 1985; Reed-Smith 2001, personal observation).
Recent evidence suggests that this species also may be capable of spontaneous ovulation (Bateman et al. 2009).
There is evidence that breeding season varies somewhat with latitude (Reed-Smith 1994, 2001; Bateman
et al. 2005, 2009), and also may be influenced by seasonal availability of food resources (Crait et al. 2006);
however the authors of the one study (Crait et al. 2006) speculating on the influence of food availability
acknowledge there could have been other things occurring and their sample size was small. In general, breeding
occurs in late spring (March-June) at northern latitudes, and between November-February at more southern
latitudes, with a gradient in between (Reed-Smith 2001). The estrus period lasts approximately 42-46 days, unless
mating occurs (Chanin 1985). Bateman et al. (2009) found that “…peaks in fecal estrogen values occurred only
during the defined breeding season from December to March”. They also report, “…the estrus phase of their cycles
[N=11] was observed just once per year with an average duration of 15.33±1.98 days (range: 6–54 days). The
average duration of estrus elevation coincident with observed breeding (n=4) was 22.00±1.22 days (range: 19–24
days).” During this time, captive observations suggest peaks of maximum receptivity are roughly 3-6 days apart
with intervals of only mild receptivity during which the female may completely reject the male (Liers 1951; Reed-
Smith 2001). The work done by Bateman et al. calls into question the estrus duration of 42 to 46 days traditionally
cited; this is an area that should be researched further. Worth noting is the slightly longer estrus (21-23 days)
reported in breeding versus non-breeding females (14-17 days); also the widely varying range of estrus duration
(6-54 days) reported in the Bateman et al. study.
More recently Bateman et al. (2009) have reported some additional interesting results from fecal
hormone studies:
“In the observed pregnancies and pseudopregnancies (n= 12), the date of initial
progesterone increase ranged from September 4 to January 14, and the timing
was not correlated (r=0.53, P>0.05) with the female’s geographic latitude
(range: 27–41°N) at the time of the pregnancy or pseudopregnancy. However,
the date of the progesterone increase was correlated (r=0.66, P