"You only have to take one look at them to know they're amazing animals and they're a tremendous part of the story of aquatic life," said aquarium director Kevin Keppel on Thursday.
Half of the $1 million went to support for Button and Genny, such as water-quality improvements and enrichment activities (the hippos spend about 90 percent of their time in the water). The other half went to the exhibit aesthetics to benefit visitors.
"This wasn't just making the experience for guests better," Keppel said. "It was also making life for Button and Genny more fulfilling."
Ann Marie Bisagno, who works as supervisor of birds and mammals at the aquarium, said that along with feeding and cleaning the hippos, her job is to ensure they stay engaged and entertained.
"You're making things different in their environment. Instead of putting them out in their exhibit and feeding them a pile of food, we look at their natural instincts - how they feed, what they do in a day. You're trying to create an environment where they don't get bored."
Genny, short for Genevieve, is the larger of the two at 4,000 pounds. She came to the aquarium from Disney's Animal Kingdom in Florida. Button, born in Mexico City, weighs 3,000 pounds. Genny is more playful, more curious and interactive with guests, and a darker gray, Bisagno said. Button tends to stay more to herself and has more of a pinkish hue. They're trained to get onto a scale, follow a target pole, lie down, and open their mouths so workers can file their teeth.
There is limited direct contact between trainers and the hippos, who are considered to be extremely territorial and dangerous. Trainers stay behind the glass or in backup areas at a safe distance. "Even though we know them and have a good relationship with them, we're never under that fantasy where we can just walk into the tank," Bisagno said. "You just never know. Who wants to take that risk?"
At a media event Thursday, Keppel and Bisagno threw large heads of Romaine lettuce into the tank for the hippos to gobble up as cameras flashed. The teenagers typically eat 30 pounds of food a day, mostly hay. Hippos can live to be about 60 years old.
On Sunday, the aquarium is holding an official opening party to celebrate the new hippo digs. The aquarium saw about a 15 percent drop in attendance this snowy winter compared with last winter, so Keppel said he's hoping the hippopotamus exhibit draws crowds in the coming months.
"We're expecting a big summer," he said. "Especially with these two."