International Giant Otter Studbook Husbandry and Management

possible. (See Chapter 5 for how to measure, Chapter 4 for when otters grow to full size/
general growth rates, Tables 6-7 & Graph 2 for body weights & lengths, and Chapter 3 for
husbandry training.) This data must only be attained from cubs that are handreared. Parents
rearing cubs and cubs themselves should never be disturbed/approached/handled to attain this or
other information or to perform procedures (e.g. sex determination, transponder implants, etc.)
that are not necessary to sustain the cubs’ livelihood. Massive disturbance, parental cub abuse
or neglect, or/and litter loss could result. If although, a parent-reared cub must be temporarily
pulled for medical treatment/vaccination or for some other crucial reason, these measurements
might be able to be quickly taken at that time. It is important that this data is shared as it can be
used to help expand the incomplete curve that is included within this manual. Handlers should
wear plastic/surgical gloves to help prevent that parents smell that the cub has been touched by
humans. See other techniques that should be used if intervention is necessary in Chapter 2.)
Behavioral and physical (i.e. abilities) development (e.g. first eating fish, swimming, or leaving
the nestbox on its own, etc.) should also be recorded and shared. This will help biologists to
determine the age of wild born cubs and comparisons can be made with other hand and parent
reared cubs. Also requested is information on adult body length and corresponding weights and
sexes for comparison to giant otters in the wild. E.g. biologists are interested to find out if a
difference in female and male body size exists (Hajek, pers. comm.). In this case however, a
rather large sample size of otters is needed to properly conduct this project. Measurements
should only be taken through husbandry training or when the otter has been anesthetized for
another reason. An otter should be measured from the tip of its tail to its nose and again from its
tail base to its tail tip. The otter’s entire body (including its tail, which is a significant amount of
weight) should be weighed.
Concerns/reports that some births go undetected (i.e. cubs are eaten in infancy or at a very
young age and no remains are found) suggest that more litters may have been born than were
recorded (Louzada da Silva, pers. comm.). It is important that these suspicions are thoroughly
documented. If a significantly higher number of litters are born than are reported, this could
have a substantial impact on cub-rearing success figures.
Detailed records of estrus and mating (i.e. dates & behaviors), the female’s physical appearance
during pregnancy/false pregnancy, and behaviors indicative of birth should be kept as they can
help detect possible pregnancies and births. Pair compatibility should also be reported.
Monitoring methods that do not disturb otters rearing cubs (i.e. infra-red video cameras with
microphones in nestboxes, dens and enclosures) function as an unintrusive way to detect births,
as well as to monitor cub health and development and parental care. (When video cameras are
not available otters might be able to be quietly watched from an area outside of the otter
enclosure that hides and isolates the observer, as long as the otters are unaware of and
undisturbed by the observer’s presence. A baby sound monitor can be used to monitor
vocalizations. The vocalizations of cubs and parents will tell as much about what is occurring,
as visual pictures will. Otter vocalizations are just as important to determine the health and
contentment of the cubs and parents, as are visual pictures. See Chapter 2 for more information
on monitoring methods and privacy during cub-rearing.)
Reports of delayed implantation have been implied (Flügger 1997), so this should also be
recorded if suspected. Hormonal studies (via sampling of feces/spraint) could be conducted to
help determine estrus cycles. Using portable ultrasound, via husbandry training only, is highly
recommended to confirm false pregnancies or actual pregnancies, view fetuses, and to
determine health and uterine condition during pregnancy or after litter loss. It is also
recommended so that institutions can make comparisons between their females and other health
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