International Giant Otter Studbook Husbandry and Management

22.34 ft] (11 sites) ; Kabo creek (Tibiti river) 12.25 m x 6.96 [40.19 ft x 22.84 ft] (16 sites), and
Kaboeri creek 8.94 m x 5.99 [29.33 ft x 19.65 ft] (50 sites).” Sites although have been recorded
to be as long as 28 m (91.87 ft) in length and as wide as 14.7 m (48.23 ft) in width. Generally
sites (as well as latrines) are enlarged with each subsequent visit.
The provision of stable support structures, e.g. very large logs or boulders, wooden
constructions etc., for otters to dig under may help prevent natural underground dens from
caving in. Additionally, trees, large bushes, or large tree stumps with long extended roots
may help prevent cave-ins and soil/hill erosion so they are highly recommended. Dens
should be checked for stability (i.e. cave-ins). One institution, Belem Zoo in Brazil, reported
that the dens that giant otters dug caved in. The otters were although able to successfully dig a
den under a concrete nestbox, that was already within the enclosure, as it acted as a support
structure for the natural den. A cub was reared successfully in this natural den. It is interesting
to note that the parents rearing cubs preferred to rear their cub in the natural dens, rather than in
the (artificial) concrete nestbox already available.
Multiple successful litters were reared in otter-dug underground dens at three of the six zoos
world-wide and historically with successfully reared litters. Two of these successful zoos had
expansive semi-natural or natural exhibits (i.e. enclosures at least 600m² (6,458.4 ft²) or more in
size) as well, which is also very important to aid successful cub-rearing. This is because the size
of the enclosure alone provided a great deal of privacy and the optimal enclosure conditions
offered many other benefits as well. Note: one of the pairs to give birth at one of the
aforementioned institutions with otter-dug underground dens, Museu Paraense Emilio Goeldi
(Belem, Brazil), was loaned to a private facility called Criatorio Crocodilo Safari (Belem,
Brazil). Because this same pair gave birth to at least one or more successful litters at both of the
two aforementioned institutions, these two institutions are associated, and no other breeding
pairs were known to be held at these institutions, these two institutions are counted, except
where noted (see below), as one institution for all data within this manual. The facilities are
also referred to as “Belem”. If these two institutions were not counted as one, then in total
(historically and world-wide) three institutions had expansive semi-natural or natural enclosures.
As well, it is assumed that four had natural underground dens (three institutions where known to
have underground dens), where cubs were reared successfully. The total number of institutions
to successfully rear cubs would then also have to be increased to seven. See the international
and historical cub-rearing statistics in Tables 2-3.
At Brasilia Zoo (Brazil) their semi-natural 635 m 2 (6,835 ft²) outdoor exhibit, with an 85% land
to 15% water ratio, vegetation (i.e. grass etc.), and land areas nearly entirely covered with soft
loose natural soil (i.e. Non-ferric Red Latosol), offers plentiful hillsides where the otters dug/dig
many underground dens throughout. All of their many successful litters (from several pairs of
parents) were reared in these underground dens and the otters slept/sleep in the dens nightly.
(No nestboxes or indoor enclosures needed to be provided.) With a high frequency throughout
the day the animals groom, dry, rub, roll, scratch, and dig on/into the surface of the soil and they
dig deep into the soft soil on the hillsides. The expanse of the enclosure and land area, the
natural underground dens, the large expanse of hillsides provided to accommodate the dens, and
the optimal enclosure conditions were very important to aid successful cub-rearing. Two thirds
of the giant enclosure land area perimeter is surrounded by hills (i.e. one continuous large hill)
with approx. a 40-45 o angle and they are extended at least 2 m (6.56 ft) high or more. The base
of the hills are located behind and near the water’s edge/shoreline and at the top of the hills is an
expansive level flat land area. A large stand of bamboo formerly grew in part of the large open
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