Perched on a sunny rock in the middle of the penguin exhibit, I watched as the penguin trainer next to me quietly vibrated with happiness. She was overjoyed because a shy young penguin, who had never liked her much despite bonding well with some of the male trainers, had climbed into her lap. Being an animal trainer, of course, she wasn’t going to let the opportunity slide to reinforce this behavior so it would occur more often in the future. She was gently rubbing the penguin on his chest. This startled me: dog trainers insist that the best reward is food. Why was she using physical contact, something that is considered insufficient reward in most other species?
The answer lies just in the practicality of feeding these birds. Unlike sea lions, who go through several buckets packed with fish a day, the little African penguins this trainer works with may eat as few as two herring a day. That’s just two chances to reinforce behavior. I asked why they didn’t cut the fish up into tiny little pieces instead of offering them whole, but watching feeding time made that more clear: feeding a penguin is a careful dance of getting the food down their throat (they often refuse, and what was the favorite kind of fish yesterday may have fallen competely out of favor today) and keeping the trainer’s fingers from getting munched in the process. All the penguin trainers had nets of scars on their hands from interactions with these birds, and were very blasé about being bitten; I was bitten three times in the calves during my short six hours with the birds. (Once was my fault for getting too close to a chick when her mom was nearby, but I can’t quite see how I could have avoided the other two times.) Throwing little pieces of fish is impractical, not to mention difficult in a flock of 27 birds.
So the trainers gradually condition the penguins to like being petted, so they can feel that they are being preened as another bird would do it. Where food is considered a “primary reinforcer” (something the animal requires to live), preening is a “secondary reinforcer” (something the animal has been conditioned to like). In the penguin trainer community, however, there is debate about whether preening could actually be considered a primary reinforcer, as arguably keeping oneself clean of parasites is essential for life.
Either way, an hour spent on a rock surrounded by 27 penguins is an hour well spent.