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Training Marine Mammals

by The National Aquarium In Baltimore

Marine mammals like seals, sea lions, whales and dolphins have a number of interesting natural behaviors and skills which speak curiosity in people. While visiting zoos and aquariums, most enjoy watching these animals perform behaviors while interacting with the trainers. Trainers have worked with marine mammals for about forty years in captive environments. Through the years, most philosophies of training have evolved to reinforce the behavior you want to see again and ignore behaviors you do not want to see again.

Animals, like people, learn at different rates, and there is no set time for learning and training certain behaviors. One thing that helps trainers teach animals is discovering what an animal finds reinforcing. A reinforcer is anything that increases the frequency of behavior. Reinforcers can be fish (some animals eat up to 50 pounds per day), toys, rubdowns or other touch, swimming with the trainer, or even learning a new behavior.

Trainers use several tools to help them work with the animals. One, known as a bridge is a stimulus (either a whistle or verbal stimulus such as "good") that the trainer uses to communicate the precise moment an animal does something correct. The term bridge is used to describe the stimulus because it bridges the gap between the behavior and the reinforcer. This immediate feedback is important because the animal may be in the water far away from the trainer and needs to know which behavior was correct. With marine mammals, a high-pitched whistle is often used as a bridge because it can be heard above or below water and is always the same. Consistency is important.

Through classical conditioning (Pavlov), the bridge stimulus is paired with a primary reinforcer, like the food or a rubdown. After the numerous trials, the bridge becomes associated with reinforcement and becomes a conditioned (or secondary)reinforcement. The animal has learned that a whistle means it has done something correctly and that it can expect a reinforcer of some sort.

Another training tool is a target. The target is usually either a trainer's hand or a small ball at the end of a pole. The ball acts as an extension of the trainer's hand. Most often, animals are trained to touch the target with their nose or mouth. The trainer can move the target up, down, left, right, forward, backward, etc. Each time the animal touches the target, the bridge stimulus is given (meaning essentially "yes" to the animal). The target is reinforced through operant conditioning.In operant conditioning, the animal's action that is reinforced will become more frequently performed. Through positive reinforcement of operant behaviors, and the conditioning of a bridge and target, almost any behavior is possible to train. However, it is important to remember that conditioned behaviors may take months or even years to train. Training takes place in small steps called approximations.

Animals make mistakes from time to time. When an animal is correct, reinforcement is given in a variety of ways: fish, toys, play, rubdowns, etc. If an animal refuses a behavior or does it incorrectly, the trainer will simply do nothing to draw attention to this behavior. This 3-4 second neutral pause is called a Least Reinforcing Stimulus, or LRS. It is like a short "time out". By keeping with the philosophy or reinforcing correct behavior and ignoring incorrect behavior, trainers are able to work with the animals in a positive manner.

Finally, the animal needs to learn a specific signal for each behavior. The signal is conditioned through a combination of classical and operant procedures. The animal learns to perform the correct behavior when asked and can "operate" on its environment to elicit reinforcement. Hence the term operant conditioning. It is important to remember that only positives are used to conditon the seals and dolphins at the National Aquarium in Baltimore.