International Giant Otter Studbook Husbandry and Management

animal, e.g. for serious/life threatening health problems. Because of the critical situation of this
species in captivity, no risk should be taken.]
It is crucial that every holding institution keeps and openly shares these records. It is also
necessary that this shared information be compiled so that comparisons and study can be carried
out. Such information is needed as a reference source for giant otters in the wild, as well as for
comparison studies in captivity. Often such records have not been kept, thoroughly
documented, or shared among institutions therefore comparisons have been difficult or
impossible to make and many questions exist. Advancing management methods and
knowledge, increasing the number of captive-born individuals, and the support for conservation
efforts in the wild will be hindered until these uncertainties can be studied and explained. (See
Chapters 2-5 and Section 5 and Part C below for more information on these issues. Section 2
and Part A above and Section 5 below describe other aspects, not included within Part B, that
need further study.)
Aspects that need further study include: estrus cycling, delayed implantation (Flügger 1997),
gestation periods, earliest age of sexual maturity for both sexes (i.e. mating), earliest and latest
age of siring/bearing litters, undetected litter births, parental behavior during cub-rearing, and
cub development and health. False pregnancies (which are not uncommon) and female
reproduction capabilities (estrus, bearing litters etc.) during late age (esp. around approx. 10 to
11 years old) and possible associated health problems should be more thoroughly studied. (At
least some female giant otters, may slow/end in reproductive capabilities or experience
difficulties/health problems during reproduction because of advancing age or/and a high number
of litter births during their lifetimes.) See below how portable ultrasounds can be used to
study/monitor pregnancy and uterine condition and health. Recently it has been reported that a
few giant otters, that are sexually mature and that have been paired together for nearly a year or
more, have mated, but the females did not become pregnant. At least two of these animals have
also been reported to display estrus cycles/mating at unusual intervals. It should be determined
if there is a trend in these occurrences and what the causes may be. A significant number of
zoos report false pregnancies. It should be determined why they are occurring at this frequency
and what is causing them to occur. How cub-rearing success is effected by parents rearing more
than one litter at a time and how the same is effected by the presence of juveniles/sub-adults
during cub-rearing should be more thoroughly studied (see Chapter 2 Section 10). Detailed
records should be kept and shared on all of these issues/aspects.
Hormonal studies (via sampling of feces/spraint) should be conducted so that estrus cycling can
be more thoroughly evaluated. Milk (lactation) samples should be drawn, only after litter loss
and through husbandry training, so that the nutritional content of mothers’ milk can be analyzed
to help determine which milk replacers are ideal for handrearing cubs. (See Section 5 below and
Chapter 5 on why giant otter milk sampling is important.) Physiological values, such as heart
and respiration rate and body temperature when the animal is not under stress or anesthesia are
needed. This can be done via husbandry training only, as true/normal values will be altered
under stress/anesthesia. When the animal is under anesthesia these values and blood samples
(i.e. chemistry) should also be recorded/analyzed for comparison. Cub body temperatures and
similar physiological values should be taken during handrearing.
Field researchers are currently requesting information on the earliest age of sexual maturity for
both males and females and the earliest age of siring/bearing litters. They are also in need of a
body weight and length growth curve with corresponding age for cubs throughout their entire
development. I.e. measurements should be taken from the earliest age to the latest age that is
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