Smithsonian National Zoological Park l Friends of the National Zoo



Water Worlds

Glide through the Amazon with freshwater stingrays. Dive into the Technicolor real of corals and anemones. Come face-to-face with a giant octopus. Try not to grin as otters perform like they're auditioning for Cirque du Soleil.

By Kerry Gildea Beck

You don’t need gills, or scuba gear, to take in these underwater wonders. You don’t need a plane ticket or passport either. All you need to do is bring your eyes and imagination to the Smithsonian’s National Zoo, where aquatic exhibits allow visitors to explore the habitats of water-reliant animals without ever leaving dry land.

Amazonia fish tanks

A visitor watches fish at the Amazonia exhibit. (Jessie Cohen/NZP)

"There’s actually an aquarium within the Zoo,” says senior curator Ed Bronikowski. “Countless species that live in the aquatic environment are spread in exhibits throughout the Zoo. Many people don’t get to travel the world, and even fewer get to peer underwater at exotic places. So we’re showing that other world that’s the least familiar to our guests.”

Here at the Zoo, that least familiar world includes 99 exhibits. They are home to thousands of aquatic animals that live in and rely on more than 1.6 million gallons of water. Let’s amble by a few of the Zoo’s water worlds.

Spineless Wonders

Some of the Zoo’s wildest looking aquatic species live at the Invertebrate Exhibit, one of the Zoo’s pioneering displays. Before the exhibit opened in 1987, curator Alan Peters explains, zoos generally didn’t track or display invertebrates. “We were the first to put them up front,” he says.

Green tree python

Green anemones (Jessie Cohen/NZP)

Pointing to a 500-gallon tank where hundreds of coral tentacles wave in the current, Peters says, “We want people to know what invertebrates are, what they do, and why they’re important.” Visitors are invited to “dive” into the 12,355 gallons of water spread out through a variety of tanks to see what invertebrate environments are really like.

Large orange sunflower stars move remarkably fast for sea stars and put on an interesting show at feeding time. Next up are brilliant pink and lime green anemones coexisting with deep purple sea urchins and majestic blue sea stars, representing the colder regions of the deep. The extreme intelligence of the giant Pacific octopus is another highlight of the exhibit as interpreters and keepers conduct a variety of enrichment and feeding demonstrations.

“People get to the end of the hallway wowed by the diversity,” Peters says, explaining that he thinks of each tank as its own ecosystem. “Tanks are made up of water, gravel, filters, animals that feed and produce waste all in the same space. It’s a block of water, and we make that block of water become their ocean.”

A Giant Challenge

Around the corner from the Invertebrate Exhibit stands the Reptile Discovery Center (RDC), many of whose residents require pools of water. These include the green anaconda, the world’s largest snake; assorted crocodilians; and Merten’s water monitor, which is equipped with unusual nostril flaps that keep water out of the animal’s nose when it takes a dive.

Filling all those tanks and pools takes 67,000 gallons of water. And that’s not counting the 10,000 gallons needed to house the Zoo’s newly acquired Japanese giant salamanders in the RDC and on Asia Trail.

Aside from the breathtaking quantities of water needed, there’s also the issue of water quality. “You can’t just drop amphibians in Washington, D.C., tap water,” notes RDC curator Jim Murphy. “They would die.” Amphibians’ permeable skin, he explains, makes them particularly vulnerable to chemicals in their water. “You need to think like a chemist,” Murphy says, “and we have a volunteer on staff with a Ph.D. in chemistry who conducts those water-quality checks.”

Before the salamanders arrived last December, the staff used a very precise process to stabilize the water’s pH and to ensure that water temperatures would replicate the seasonal changes of the animals’ stream habitat.

Exploring an Ecosystem

Downhill and across the Zoo, Amazonia is a don’t-miss destination for lovers of aquatic animals. Holding 62,300 gallons of water, its tanks showcase underwater species from one of the largest and most biodiverse ecosystems in the world.

“The whole Amazonia exhibit is built like an ecosystem,” says curator Vince Rico. Visitors get a “full rainforest experience,” he adds. Upon entering, people are immersed in the flooded forest, eye level with speckled freshwater stingrays, discus fish, and a somewhat skittish spotted pike characin. Meantime, poison dart frogs chirp from beneath the rainforest plants.

"Wow! You gotta see this!” echoes from a darkened hallway as visitors turn the corner and encounter the giant river fish pool. The sheer size of the freshwater swimmers—including the air-breathing arapaima, which can grow eight feet long—stuns visitors.

Green tree python

Pink-tipped anemone (Jessie Cohen/NZP)

"These fish help us bring home the diversity of the rainforest,” says biologist Ed Smith. He sometimes quizzes visitors about how many species of catfish exist locally and throughout the United States. Most people can name one or two. “The Amazon, which occupies an area the same size as the United States, has more than a thousand species of catfish,” Smith explains. “This diversity of life is typical of most groups of organisms found in the tropics, particularly the neotropics.”

“We also feature one of the Amazon’s most infamous fish—the piranha,” says Smith. “Its reputation has been made by Hollywood, when in reality more piranhas have been eaten by people than the other way around.”

Feeding time at Amazonia provides an opportunity to dispel myths. While large size may make one think of fierce predators, many of the river fish rely on vegetation that falls into the water and much prefer bananas, grapes, and lettuce.

Exploring Amazonia isn’t simply a chance to see striking aquatic creatures. It’s an opportunity to appreciate an entire ecosystem—one of the most valuable and vulnerable on Earth. “The awe and wonderment of the Amazon region,” says Rico, “helps people see what they can do to protect this and our own region."

Constructing a Coastline

Beyond Amazonia lies a construction zone. It will be home to a revamped Beaver Valley exhibit, due to open in 2012. The exhibit will be an aquatic extravaganza, with a 300,000-gallon pool for California sea lions, a 125,000-gallon pool for seals, a 27,000-gallon pool for American beavers, and an 8,000-gallon pool for North American river otters.


California sea lion (Mehgan Murphy/NZP)

Visitors to the new exhibit will literally be able to get their feet wet in an artificial tide pool, giving them a more realistic feel for coastal habitats. They may also get a taste of coastal biodiversity. “There is a narrow band on the California coast,” says exhibit developer Cheryl Braunstein, “where the brown pelican, bald eagle, California sea lion, and harbor seal all coexist. Capturing that in a zoo environment would be very special.”

Underwater viewing areas will make it possible for visitors to compare their breath-holding ability with that of seals and sea lions. “We’re pretty closely related to them as mammals,” Braunstein says. “We all like the water; we like to swim. But these mammals can really swim. One of the things we want to capitalize on is the difference between seals, sea lions, and you.”

The new exhibit represents dramatic advances in marine mammal care from when the Zoo’s first exhibit was built more than 30 years ago. “The improvements in life-support systems and filtration have greatly improved,” notes Rico, “and we have more sophisticated husbandry that makes it an overall better existence for all our animals.”

Invisible Efforts

Ensuring a better existence for aquatic animals is no small challenge. Keeping the Zoo’s water-reliant animals healthy requires sophisticated life-support systems, precise water-temperature controls, proper pH levels, complex filtration, and in many cases reverse-osmosis mechanisms to remove the incoming water’s minerals. For the ocean-dwelling species, salts actually have to be added into their tanks.

Gaboon viper eye

Giant Pacific octopus (Mehgan Murphy/NZP)

The Zoo’s animal-care and operations staffs do everything from monitoring exhibit-water quality to ensuring that the plumbing, filtration, and complex exhibit-management systems all function properly around the clock. And, like the animals, pumps and pipes also need checkups.

“Just as a doctor listens to a person’s heartbeat to see if he or she is healthy, our team listens to the pumps and pipes,” says Dan Davies, the Zoo’s director of facilities. Zoo workers monitor the water system with the same meticulous care that keepers devote to the health of the animals. Some Zoo veterans can walk into a building and hear straightaway if there’s a problem with a particular tank or filtration system. Yet the Zoo doesn’t simply rely on well-trained eyes and ears. A system with thousands of sensors is ever ready to alert the staff to any problems.

If the Zoo team is successful, visitors should never realize it. “We hope the visitors never know we’re here,” Davies remarks. “If they’ve had a positive experience, they shouldn’t know the water is running and being pumped. They should feel they are in the animal’s habitat. The glass, the enclosure should go away. It should feel like magic.”


—KERRY GILDEA BECK is a freelance writer and volunteer interpreter at the Amazonia exhibit.


More: "Troubled Waters"


If you have a comment about Smithsonian Zoogoer magazine, please email it to us.

Smithsonian Zoogoer 39(6) 2010. Copyright 2010 Friends of the National Zoo. All rights reserved.