International Giant Otter Studbook Husbandry and Management

the husbandry practices recommended during cub-rearing are also necessary to provide
privacy. The only husbandry practice that might not be necessary is the isolation of the entire
enclosure from visitor viewing. If the enclosure is very expansive, i.e. well above 600m², this
may likely not be required. When the enclosure is not very expansive it might need to be
isolated from visitor viewing. E.g. the enclosure at Brasilia Zoo is 635m² and it has many
natural underground dens, but the exhibit is also sunken well below visitor level and this
contributed to additional privacy. Note: keeper activities were significantly minimized as well.
For some litters, visitor viewing was also restricted. See Part A above. Section 12 below lists
the institutions that used expansive enclosure designs and/or natural underground dens during
successful cub-rearing and it includes a brief description of each enclosure. See throughout
Chapter 2 for more details on some of the enclosures and cub-rearing experiences.
The provision of expansive 1 complexly and naturally enriched enclosures with hills that
offer otters ample area to dig underground dens is optimal. 1 Within this manual “expansive
enclosure” means any enclosure that is 600 m 2 [6,458.4 ft²] or larger. The larger, more
complex, and natural the enclosure, the more benefits gained. (The enclosure also requires the
recommended land and water area designs and locations [esp. appropriate land to water ratios
that provide enough land], substrates, deep digging area sizes, and hill designs and locations to
offer these benefits.) This type of living area provides optimal enrichment and living
conditions for giant otters and it is very important to help aid successful cub-rearing. This
is because the larger the enclosure, the further parents can get away from human
disturbances and presence during cub-rearing (i.e. the more privacy they have) and as well,
natural underground dens provide additional visual and acoustic isolation. The otters are
offered an optimal area where they can carry out, to the fullest extent possible in captivity, the
innate terrestrial behaviors that are among the most important activities needed to allow these
animals to significantly reduce or prevent the negative responses (i.e. stress, nervousness,
boredom etc.) that can occur and cause significant problems (e.g. litter loss) during cub-rearing.
Dens that the otters dig themselves provide a great amount of isolation in combination with an
expansive enclosure or an enclosure that is totally isolated. These den types are highly
recommended and are very important to promote successful cub-rearing in all enclosures.
Wild Pteronura use the multiple underground dens that they dig within their vast territory, to
rear cubs and sleep in. When given the appropriate conditions, i.e. substrate types and hill
designs as recommended, captive Pteronura will also dig many underground dens throughout
the expanse of the hillsides/banks provided and use them for the same purposes. Underground
dens are fairly visually and acoustically isolated, i.e. more so than a wooden nestbox, natural for
otters to rear their litters in, and private and safe feeling for the otters. They do not have to be
serviced or maintained by keepers because the soft loose substrates in them keep the dens clean,
dry, and sanitary when land to water ratios, other land and water area designs and locations,
substrates, and hillside locations and designs are provided as recommended. (No bedding
materials need to be offered within them.) The fact alone that humans usually do not enter
underground dens (esp. in comparison to a nestbox, den containing a nestbox, or artificial
underground nestbox), adds to feeling of seclusion and safety from human intrusions and
disturbances.
Giant otter enclosures and any buildings housing such enclosures should be designed and
located within the zoo so that they can be isolated from all visitors/public and zoo staff
during cub-rearing, yet still allow minimal keeper activity in limited areas without
creating human disturbance. It is necessary to provide multiple nestboxes, dens
containing nestboxes, or natural underground dens where human entrance can be
restricted during cub-rearing (see below). Nestboxes, dens, and areas for underground
155