International Giant Otter Studbook Husbandry and Management

last litter at which time she died during recovery from surgery for pyometra (Flügger 1997).
[Flügger reported that the female was 9 years old at the time she had pyometra, although it was
later found, after this article was published, that this female was actually 11 years old at this
time (Louzada da Silva, pers. comm.).] At the time that this female died, her mate was 7 years
old.
A 9 year and 4 month old captive giant otter, at Dortmund Zoo, gave birth to a litter after 77
days of gestation. (The gestation period was counted from the last day of mating seen.) This
was the longest gestation time recorded for her (Gatz, pers. comm.). (Usually although, her
gestation period was no shorter than 70 days.) She exhibited this long gestation period two
times total. The other occasion occurred 4 years before this litter. This mother’s teats became
visibly enlarged 4 weeks before parturition and the vulva was noticeably swollen roughly
around a week before parturition (Gatz & Sykes-Gatz pers. comm.). She otherwise showed no
signs of imminent parturition (i.e. she ate and acted normally). Only when this female reached a
later age, she slowed in activity approx. 2 weeks before parturition.
During the aforementioned female’s latest litter (i.e. at 9 years and 4 months old), this mother
aborted decomposing fetus parts (possibly only 1 cub) 4-5 hours before the live births occurred
(Sykes-Gatz, pers. obs.). The mother then gave birth (around 1 p.m.) to 2 cubs spaced 10
minutes apart. Her mate remained at her side during parturition. With most of her previous
litters, the cubs were usually first detected in the morning hours (when keepers arrived to work).
The mother placed the cubs on her teats and toileted the cubs frequently throughout the 7 days
the cub/cubs were observed (Sykes-Gatz pers. obs.) The first cub died at 5 days old and the
second was pulled for handrearing after its 7 th day of life. After the remaining cub was pulled
and during the next one year and 7 months she missed all of her normal estruses (including the
post-partum/after the litter loss and once every 3 months estruses) that she usually would
experience. (I.e. in 7 years she gave birth to 13 litters/28 cubs.) In total, she missed 7 estrus
cycles during this period and no mating occurred. (She was 11 years old and her mate was
almost 14 years old at the time this was reported.) Although, during this time, she exhibited
false pregnancies at least twice. Ultrasounds, conducted via husbandry training only, showed no
fetuses were present. This method was also used to detect an actual pregnancy and determine
the health/physical condition of her uterus. Her reproductive capabilities may be slowing
because of her advancing age and she may have more difficulty if she does reproduce again (i.e.
in light of the aborted decomposing fetus). It is although expected that she will never breed
again because of her late age. A third false pregnancy was confirmed, via ultrasound by
husbandry training, after the aforementioned was reported and no mating was seen beforehand.
(Ultrasounds for such procedures should only be carried out by husbandry training. Otters
should not be anesthetized for ultrasounds unless it is a medical emergency. It is not worth the
risk of death that could occur.)
The past two females (within two zoos) showed difficulty/health problems during pregnancy
or/and slowing (or possibly permanently ended) estrus cycles/mating periods in their later age.
They both also had a large number of litters during their lifetime and gave birth to an average of
2 litters per year. [It is important to note that normally otters in the wild only have one litter per
year and the oldest documented life-span was eight years for free-ranging giant otters (Staib &
Schenck 1994). The oldest known giant otter in captivity survived to at least 19 years of age,
although this is exceptional and this age is only an estimation. This animal was a female.] This
indicates that at least some giant otter females, around 10 to 11 years old, may slow/end in
reproductive capabilities or/and have difficulties/health problems during gestation/reproduction,
because of advancing age or/and a high number of litter births during their lifetime. Although
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