International Giant Otter Studbook Husbandry and Management

part of the target. The target we use at Dortmund Zoo is a long stick with a yellow wooden ball
on one end, or – for small fence openings – a long stick with yellow duct tape on one end (i.e.
the color and shape of the end of the target makes it easy to focus on). We use both targets
simultaneously as well as independently. The target can be used to lead an animal through
small steps of a behavior.
Bridge
A bridge stimulus, such as blowing a whistle or simply the word “good”, is an immediate signal
to let the otter know that a behavior is done correctly. The bridge is paired with a reinforcer or
reward, which is anything that increases the frequency of the behavior. In the otters’ case, it’s
usually food or a favorite toy - something that the animal enjoys and looks forward to get. The
bridge becomes connected with the reward and the animal learns to perform the behavior in
order to get this reward. It is important that an animal knows immediately when it has
performed correctly. A delay of even a few seconds may cause significant problems. The
animal learns that when it hears the bridge it can return to the trainer to receive a reward.
Reward / Reinforcer
The most common reinforcement or reward is food. The giant otters at Dortmund Zoo favor
mackerel, but it is not part of their regular diet as it is considered to be too fatty and not good for
the health if it is fed as the main diet, too frequently etc.. Otherwise, in small amounts and
small pieces, it is a great reinforcer during a training session. We have also found at Dortmund
Zoo that mackerel is easy to use because it is firm and does not fall apart easily. In the case of
one otter, only vocal and tactile reinforcements such as deep massages are used.
Desensitization
Every new and unfamiliar object or behavior that we expect the animal to perform has the
potential to be very scary. Every novel item or behavior must be introduced very carefully.
During the training, trainers have to guide the animal in small steps. After several successful
repetitions, trainers can move on to the next step. Unfamiliar objects should be introduced
slowly and gently so as not to scare the animal and to make the animal feel comfortable around
the object. As well, the presence of unfamiliar or excess familiar persons during a training or
husbandry procedure can also distract or scare the animal. Once the behavior is trained (or even
during late training if tolerated) additional familiar persons and eventually unfamiliar persons
can be introduced during training sessions to help desensitize the animals to these factors. For
example, during crate training or ultrasound training other zoo staff will need to be present
when these procedures are actually carried out, so otters should be given time to adjust to these
changes/distractions/potentially frightening events during training. As well, when vets must
perform ultrasounds, it is most helpful if they have a chance to develop a positive relationship
with the otters before or at least during/after training is carried out.
Training Frame, Dummy Portable Ultrasound & Scale Frame Used at Dortmund Zoo,
Beam Scale used at Philadelphia Zoo; Temporary Transport Crates Used at Dortmund &
Philadelphia Zoos
A wooden frame with a step was developed at Dortmund Zoo to meet the special requirements
of giant otter husbandry training. The frame and its step can be placed low in the fence lattice to
enable the otter to stand comfortably right next to the lattice. The otter is trained to station,
while it is standing on the step of the frame. Most of the otter’s body becomes easily reachable
with the frame, enabling us to perform body examinations, ultrasounds, or milk sampling. See
more details about the training frame construction under “Giant Otter Training at Dortmund
Zoo”.
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