Octopus Enrichment at the National Zoo
Toys Keep Giant Cephalopod Busy and, Maybe, Happy
Nov 15, 2009
It’s noon at the Washington National Zoo, and Augusta, the zoo’s two-year-old female octopus, is waiting.
Leila, a volunteer in the Invertebrate Exhibit, consults the schedule and selects the enrichment toy for the day: a small orange plastic octopus with openings where a treat, raw smelt, can be pushed inside.
For the first 10 minutes, Beth, another volunteer, observes Augusta to see her baseline behavior — how she acts when there is no object in the tank.
Then Leila drops the fish-stuffed toy into the water. At first, Augusta appears not to notice. Then one of her eight long arms covered with suckers pokes out and curls around the toy, drawing it toward her body. The object is quickly enveloped in the parachute-like webbing between the arms.
Octopus Changes Skin Colors and Textures
Beth stands in front of Augusta’s tank to observe and record her behavior. Zoo staff want to know if the octopus acts differently when she has intellectual stimulation, in this case the challenge of extracting the fish from the plastic toy.
“We’re looking for three things,” says Beth. “Changes in behavior, changes in color, and changes in skin texture.”
When an octopus is excited, it changes colors by contracting skin cells filled with pigment. In the wild, it does this to camouflage itself when hunting for prey such as shrimp, clams, and crabs.
As Augusta pushes and pulls at the plastic toy, her body changes from pale to mottled reddish-brown to a deep rosy red.
Changing its texture is another way that an octopus in the wild blends in with its surroundings. As Augusta handles the toy, her skin changes from smooth to bumpy and back again.
Every 60 seconds, a beeper goes off, and Beth records the octopus’s skin color and texture and her level of activity.
Enrichment Elicits Natural Behaviors
At the Washington zoo and other zoos around the world, environmental enrichment programs allow captive animals to practice the kinds of natural behaviors they would use in the wild. For an octopus, a central behavior is hunting and capturing prey.
The giant Pacific octopus (Enteroctopus dofleini) is the largest octopus species in the world. It lives in the northern Pacific Ocean, ranging from southern California up to the Pacific Northwest, across the Aleutians, and south to Japan.
Mature females have 280 suckers on each arm that are sensitive to touch and taste. The octopus uses its arms to grope for food in ocean crevices. When it finds something, it grabs the prey and stuffs it into its mouth.
In a zoo, however, animals have meals delivered to their enclosures daily. With no need to hunt or gather, some animals become passive and listless.
When Augusta seizes the enrichment object and works to extract the fish, she is practicing her natural prey-catching skills.
Benefits of Animal Enrichment Hard to Measure
Augusta is the eighth octopus to participate in the Octopus Enrichment Program at the National Zoo. The toy bin in the Invertebrate Exhibit holds dozens of objects, including a whiffle ball, a scrub brush, a jar with a lid, a rubber frog, and a flashlight.
Octopuses are considered the most intelligent of the invertebrates. In previous experiments, they have been able to find their way through mazes and unscrew jar lids. They have acute vision and relatively complex brains.
But no one knows how, or how much, a zoo octopus benefits from enrichment because there is no sure way of measuring it. It’s possible to observe an animal’s outward movements. But no one knows whether an octopus feels happier or less bored when it has a toy, or even whether it is capable of such humanlike emotions.
The data that zoo volunteers are gathering with Augusta will help biologists learn how enrichment can help zoo animals stay active and healthy.
Zoo Visitors Can Observe Octopus Feedings
Visitors to the National Zoo in Washington should check the zoo’s online daily calendar for times of octopus feedings and enrichment. The Invertebrate Exhibit is located directly behind the Reptile Discovery Center.
Other U.S. zoos that have had octopus enrichment programs include the New York Aquarium, the Monterey Bay Aquarium, the Seattle Aquarium, and the National Aquarium in Baltimore.
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