International Giant Otter Studbook Husbandry and Management

door) could instead be made in the nestbox for servicing etc. This would be useful to help keep
cubs and bedding substrates in the nestbox if the nestbox door must be opened. Nestboxes and
dens containing nestboxes should not be entered or approached during cub-rearing except
for when it is necessary to ensure the survival of the otters, i.e. for emergency or medical
care or for vaccinations (see Section 10 above). Transparent viewing areas should not be
created within nestboxes as they could detract from the feeling of safety and privacy.
Nestboxes should remain dark or if necessary infra-red lighting could be used when video
cameras (see below) do not have infrared capabilities.
Shift doors should not be attached to nestboxes, although a removable shift door can be made to
attach to the nestbox when the nestbox will be used for transporting animals for short distances
(see below). E.g. otters should be locked in dens or separable enclosure areas, and not
nestboxes, when enclosures are serviced etc.. A nestbox is too small and confined and in very
warm temperatures, too hot, for otters to be locked in them on a daily or regular basis. Also, if
parents have cubs, they should not be locked in their nestboxes together as the parents could
harm their cubs in their attempts to get out or when they are under stress. See the paragraph
below for tunnels that can be fitted with shift doors and attached to nestboxes.
It is optimal when long narrow tunnels, made of wood/plywood, are connected to the
nestbox entrance holes as they help increase privacy, keep nestboxes free of draft, help reduce
tracked in water, and keep cubs from crawling out (Duplaix-Hall 1975). The tunnel should be
detachable so the nestbox can be moved/carried around more easily and the nestbox can be
turned into a temporary transport crate if needed. The tunnel should be at least 40 cm (16")
wide and 40 cm to 60 cm (16" to 24") high. The tunnel length should be at least 1 m (3.28 ft)
long and it can range to 1.60 m (5.25 ft) long depending on den size. The tunnel entrance-way
should be placed at the tunnel’s side, not the tunnel’s end, at the farthest end from the nestbox
for extra privacy. I.e. the otters will have to turn a corner to get into the tunnel. The tunnel
entrance-way opening can be 40 cm high x 40 cm wide (16" high x 16" wide). If the tunnel is
long enough, it also can be made into an L shape for extra privacy. It is optimal when a shift
door can be placed at the tunnel end of at least one nestbox so cubs, esp. older cubs, can be
locked inside if necessary (i.e. for medical care / emergencies). The shift door frame should be
elevated, e.g. 10 cm (4”), above the tunnel floor to help prevent substrates from blocking the
shift door track. The shift door should be made of non-transparent materials so otters can not
see through the door. A non-transparent opening hatch, i.e. a wooden door, with a secondary
fence/lattice covered hatch located behind the opening hatch can be created in the tunnel. These
hatches can be used for viewing the tunnel with safety and for accessing the tunnel. This way
cubs can be removed from the tunnel if they are not directly in the nestbox and tunnel substrates
etc. can be serviced/monitored more easily. Tunnel floors should be lined with the
recommended mulch or sand types, qualities, and depths to help keep the nestboxes and
tunnel dry. Note: during warm weather, dens and nestboxes located in outdoor enclosures
could become very warm (esp. in climates that are warm all year around). Caution must be
taken if tunnels are connected to nestboxes as they may increase nestbox temperatures and
nestboxes may become too warm for the otters. Other situations could also cause nestboxes to
become too warm as well.
If tunnels are not used, a “tunnel-like entrance” could be installed within nestboxes, although a
full tunnel is much more effective and the following technique has not yet been reported to be
used during cub-rearing. The following design creates a “tunnel like entrance” within the
nestbox itself. (This nestbox was used as a sleeping box for 2.0 otters at Philadelphia Zoo).
The nestbox measures 99 cm wide x 122 cm long x 76 cm high (3.25 ft wide x 4 ft long x 2.5 ft
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