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

CHAPTER 7: Reproduction
Reproductive Physiology and Behavior
A. cinereus: These otters are non-seasonal, and thought possibly to be spontaneous ovulators (Bateman
et al. 2009). The estrous cycle lasts 30-37 days, with breeding occurring year round. Some facilities report this cycle
extending to every few months with older animals. Estrus lasts from 1-13 days. Behavioral signs of the onset of
estrus may include increased rubbing and marking. Sexual behavior has been observed in pups as young as 6
months, with breeding behavior having been noted in animals (males and females) as young as 1½ years.
Successful breeding has been reported for 2.1-year-old females and 2.8-year-old males. There do not appear to be
any significant environmental cues that are involved with the onset of estrus. Breeding pairs have been introduced
at various ages and have been together for varying lengths of time before successful breeding occurs. It has been
reported that pups from previous litters have interfered with copulation, but their presence had no bearing in any
other way (Lombardi et al. 1998).
Recent work has shed light on litter intervals; Bateman et al. (2009) report: “In one female having three
consecutive pregnancies during [their] study, the interval between the first parturition and subsequent
progesterone increases owing to the next pregnancy was 169.25±11.15 days. This female was observed nursing
her pups from the first pregnancy for the first 122 days of this intergestational time period.”
Breeding pairs must establish a bond for successful reproduction. The male pursues the female in
courtship and most breeding occurs in shallow water. A single copulation can last from 5-25 minutes. Courtship
behavior has been recorded from 1-3 days, at one-month intervals. Gestation is roughly 60-74 days (67-77 range,
average 71.17±1.49 days reported by Bateman et al. 2009).
Pseudopregnancies do occur in this species, including in females housed in single sex groups (5 of 6
females housed together exhibited pseudopregnancy) (Bateman et al. 2009). Bateman et al. (2009) report: “…a
mean duration of pseudopregnancy of 72.45±1.37 days (range: 62–84 days). The average interval length between
sequential pseudopregnancies and/or pregnancies was 39.86±3.86 days (range: 17–92 days) in paired females and
134.50±48.94 days (range: 62–279 days) in the single gender group.
The sire plays a very active role in rearing the pups, and should not be removed prior to their birth. Male
behaviors include nest building, carrying pups, and bringing food to the pups during weaning.
Table 7: Captive breeding parameters of Aonyx cinereus in North American zoological facilities 1980's and 1990's
(Reed-Smith & Polechla 2002, Bateman et al. 2009)
Aonyx cinereus
Estrus cycle
Estrus length
Ovulation
Copulation frequency
Copulation duration
Copulation position
Copulation location
Copulation initiated by
30-37 days. Polyestrual with breeding occurring year around
1-10 days
Likely spontaneous ovulators (Bateman et al. 2009)
Several times a day.
1-30 minutes, varied.
Dorsal/Ventral most common, also ventro/ventral.
In the water and on land
Varies amongst groups, in some it is initiated by male only, in others both
initiate.
Age at 1 st breeding
Breeding behavior
Unknown
Increased rubbing, marking.
Gestation Gestation ranges between 67 and 74 days; pseudopregnancies lasted 62 –
84 days (Bateman et al. 2009). No delayed implantation (Bateman et al.
2009)
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