International Giant Otter Studbook Husbandry and Management

Deep Digging Area Necessary For Each Enclosure
In addition to the necessary land and floor substrates aforementioned, each indoor enclosure
(see exceptions below) and each outdoor enclosure must have at least a 40 m 2 (430.56 ft²) area or
significantly larger area, where soft non-abrasive sand or mulch, a minimum of 40 cm to 60 cm
(16” to 24”) in depth, or hillsides, with the recommended designs and soil qualities, allow for
deep digging. The same substrate qualities, types and husbandry techniques needed for
enclosure land and floors are also necessary for the deep digging areas (see above and below). E.g.
soil, sand, and mulch must not have pebbles, gravel, or small rocks (smooth, rounded, or
otherwise), or construction or abrasive sand mixed throughout them. Soil requires additional
specific qualities. When an indoor enclosure 75 m 2 (807.3 ft²) or below in size attaches to an outdoor
enclosure that provides at least a 40 m 2 deep digging area and otters have access to both enclosures,
the indoor enclosure requires at least a 20 m 2 (215.28 ft²) area where soft sand or mulch, a minimum
of 40 cm to 60 cm (16” to 24”) in depth, allows for deep digging. When soil is not used within
enclosures, the mulch and/or sand deep digging areas should instead cover the majority of the
land and floor surface area or nearly the entire land and floor surface area in every indoor and
outdoor enclosure and they should be as deep as possible. They should have at least 100 cm
(3.28 ft) mulch and sand depths (see below). When enclosure terrain is fairly flat and soft loose soil
(with/without turf or vegetation) is provided, otters will not be able to dig deeply, therefore plentiful
hillsides, rather than the minimum size area above, should be provided. They should border
nearly the entire length of the enclosure land area contour line. The hillsides provided should
be at least 1.8 to 2 m (5.9 ft to 6.56 ft) high and have an angle of 40-45 o . They must be made of a
soft soil type that remains, after continual use, loose enough that otters can easily dig deeply
into it, as well as, effectively groom on it. Otters must be able to dig at least 40 cm to 60 cm (16”
to 24”) in depth in these areas. The hills should not be steeper or much less steep than a 40-45 o
angle and it is recommended that they be located behind and near the water area shoreline (see
Section 5 below). For multiple reasons, it is highly recommended to provide soft sand, at least the
minimum size area and depth recommended, for deep digging, in addition to the mulch or
hillsides offered for these purposes (see above). It is necessary that any enclosure, whether it is
already in use or not, that does not provide at least the minimum recommended deep digging
area size, depth and substrate qualities and types, be modified so that it does. (See the
introduction above for modification methods.)
The recommended minimum size and depth for the deep digging area is not optimal, only
minimal. E.g. captive Pteronura can easily dig 100 cm (3.28 ft) deep into soft sand and mulch
throughout the entire expanse of their enclosures (e.g. within enclosures well above minimum
size). They as well can dig many deep underground dens throughout extensive hillsides (e.g. a
500 m 2 [5,382 ft²] area composed of hills) that have the recommended designs and substrate
furnishings. Substrate depths should be as deep as possible and deep digging areas as large
as possible. It is important although that plentiful level land area is offered when hills are
provided. (E.g. level land can be located at the top of the hills, along the water’s edge, or/and
elsewhere within outdoor enclosures and some areas can also be furnished with deep soft sand).
When otters dig significant size areas of mulch and sand to the maximum depth possible, i.e.
when significant size holes are created, these holes should be filled in again, with the substrates
dug away, so they can be re-dug. (Underground dens that are dug into soil should not be filled in
so they can be used for sleeping and keeping cubs in etc..) It is highly recommended to
additionally give a deep pile of leaves (esp. where the leaves can remain dry) for variety (i.e.
not as substitute for the required deep digging areas or substrates). Giant otters also
particularly enjoy digging, playing, rolling, and grooming in this. Leaves that have fallen from
deciduous trees are ideal. Leaves from coniferous trees or that have thorns, thistles, poisonous
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