<em>By Laura Morrell and Mike Murray, Predator Ridge Zoo Keepers
Denver Zoo, Denver, CO</em>

<strong>Abstract</strong>
At Denver Zoo, training spotted hyena (<em>Crocuta crocuta</em>) using operant conditioning has proved to be more than helpful in their mental and physical care.  We are still learning about their extreme intelligence which is often compared to that of the great apes.  Over the past years, we have trained the hyena behaviors to allow hand injections in their hip area, allow staff to look into their mouth, allow keepers to regularly weigh them, and allow staff to apply wound treatments when needed. The next challenge for us was to establish a reliable blood draw behavior.  With advice from our vet and managers, we decided to train a blood draw behavior with our two adult males.  The opportunity arose to train this behavior in two different ways.  1.0 Thika was trained a ‘neck’ behavior which gave the vets access to his jugular vein.  At the same time, 1.0 Kibo was trained a ‘leg’ behavior which gave the vets access to his lateral saphenous vein in his left rear leg.  Both of these behaviors confirmed how intelligent these animals truly are.  The training process presented obstacles with both behaviors which we overcame.  Our vets currently have the ability to effectively draw blood from either male which demonstrates the strengths of a training program founded on the principles of positive reinforcement.

<strong>Introduction</strong>
The spotted hyena (<em>Crocuta crocuta</em>) are predators that live in large social groupings known as clans and live in a variety of environments throughout sub-Saharan Africa.   The spotted hyena have an incredible intelligence that is often compared to primates and is demonstrated by the hyena collaborating on projects such as hunting on the plains of Africa and solving puzzles in captive settings (Holekamp et al., 2007).  These extremely adaptive carnivores are unique in many ways including their complex social structure that is completely dominated by females.  Males, at the bottom of the totem pole, are frequently subjected to fighting with each other to maintain a dominant rank and avoid being forced out of the clan.  This constant struggle elicits aggression between males that results in common neck injuries and open wounds.  The results of these intense battles often heal quickly due to the hyena’s strong immune system and pain tolerance which is another unique feature of the spotted hyena.

Alongside South African lions (<em>Panthera leo krugeri</em>) and African wild dogs (<em>Lycaon pictus</em>), spotted hyena have been housed at Denver Zoo’s Predator Ridge since 2004, to educate people about social carnivores in an award-winning rotational exhibit.   All of the animals in Predator Ridge, including hyena, have been participants in an elaborate training program that allows them to assist in their own health care as well as provide mental and physical stimulation.  Denver Zoo houses 2.1 spotted hyena adults and throughout the years there have been five litters producing seven cubs total.   When our hyena arrived, our female Ngozi chose to mate with Kibo over his brother Thika.  This resulted in Kibo consistently asserting his dominance over Thika by attacking him and causing reoccurring wounds to his neck and body.   The training program has allowed us to closely monitor the condition of the hyena, treat any wounds, give injections, achieve bimonthly weights, and avoid stressful immobilizations.  Our next challenge was to institute a voluntary blood draw behavior.

<strong>Methods</strong>
The first step to training a blood draw behavior with the hyena was to determine how this was going to be accomplished.  Meetings were held with management and vet staff to discuss the most ideal way to approach this task.  At the time of discussion, we chose to train a blood draw behavior in the two males because they had a positive relationship with the vets and a solid injection behavior.  Our female, at the time, had a set of cubs and was still focusing on other behaviors of importance.   Based on the incredible intelligence of spotted hyena it was decided that training a blood draw behavior could be achieved in multiple ways.  It was determined that it would be possible to train Thika to present his neck to draw blood from his jugular vein while training Kibo to present his left rear leg to draw blood from his lateral saphenous vein.

<img class="alignnone size-full wp-image-1897" title="predator_ridge1" src="http://aecetia.net/gws/aazk/wp-content/uploads/predator_ridge1.jpg" alt="predator_ridge1" width="793" height="594" />

A view of two exhibits at Predator Ridge with lions and hyenas. <em>(Photo by Mike Murray)</em>

<strong>Methods of Training Thika</strong>
The decision for choosing the jugular vein for Thika’s blood draw was based on several factors.  One justification was that hyena successfully allowed this blood draw at previous institutions, i.e. Moorpark.  Secondly, Thika frequently offered his neck to keepers since he enjoyed being scratched with a backscratcher.  Due to the fact that Thika is the subordinate male, he occasionally has neck wounds and we are able to treat his wounds with ointments and sprays.  This de-sensitivity to touch was favorable in helping the decision to train this specific behavior.

The following were the training steps for Thika’s ‘neck’ behavior:

<strong>Step 1:</strong> Informal training sessions without diet because if diet was present he would have no interest in being scratched.  Trainer approached Thika with a backscratcher.  Thika presented a side of his neck to be scratched.  Bridged (whistle) and reinforced this behavior.  Rewarded with more scratches.

<img class="alignnone size-large wp-image-1898" title="hyena" src="http://aecetia.net/gws/aazk/wp-content/uploads/hyena-1024x781.jpg" alt="hyena" width="819" height="625" />

Hyena being scratched with a backscratcher.<em> (Photo by Laura Morrell)</em>
<strong>Step 2:</strong> Similar to Step 1.  While using the backscratcher, trainer shaped his neck position to where the under side of his neck is flushed against the mesh while his face is upwards.  Bridged and reinforced using scratches.

<strong>Step 3:</strong> Once Step 2 was consistent ……..

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