It's hard to predict what will catch Hannah the pygmy hippo's fancy.

"She gets offered new items, like a traffic cone, a barrel, hay bales and natural items like bamboo and palm fronds to enrich her environment," says Ali Crumpacker, director of the Fund for Animals Wildlife Center. That's the Humane Society's California sanctuary, where this rare girl has lived in a 13,000 square foot paddock after being rescued from her previous owner's backyard about a dozen years ago.

Hannah with her 40th birthday present: a humongous soccer ball.

Pigmy hippos, which are listed as "endangered" on the IUCN Red List of Threatened Species, usually grow to between about 400 and 600 pounds -- so finding the right toys for Hannah can be tricky.

"She ignores some items, and others she plays with until they fall apart," says Crumpacker. "As a nocturnal animal, Hannah tends to play with her toys at night when the staff is not on-site. They usually only know how much she is enjoying a specific item by how dirty and dented it gets! "

One toy clearly goes into the "falls apart" category. It's a couch cushion that she was given to fool around with last October, and completely decimated over the summer. Hannah -- who will turn 41 this November, and is thought to be the oldest pygmy hippo in the country -- used the cushion as an actual pillow for a while, before going Medieval on the luckless upholstery, according to the Fund for Animals Facebook:

Recently she decided to use it as a pool toy and played with it in the water until the cover deteriorated (much to the horror of our facility crew who had to unclog the pool drain). Then she decided to use the bare cushion as a saddle. Yes, she put the pillow on her back herself [by] swimming under it as it floated in her pool and then climbing out and walking around with the soaking wet foam pad on her back. Guess it’s time to get her a new couch cushion!

For a pygmy hippo, Hannah looks gigantically pleased with her handiwork:

Hannah's other favorite things include her oversized soccer ball and a blue plastic barrel, as well as "two wild mallard ducks, who she allows to not only swim with her, but also to eat her leftover grain. But if any other birds try to do the same thing, she gets in a huff and charges at them to scare them off," says Crumpacker.

As for Hannah's dearly departed couch cushion, Crumpacker says that some replacements -- all likely to meet the same eventual fate -- are in the works.

"Either an oversized watermelon to celebrate the end of summer and/or her very own jack-o-lantern with her favorite grain inside for her to roll around until it falls out," she says. "Or until she munches through it."

See more photos of Hannah and The Fund for Animals Wildlife Center's hundreds of other animals -- including a little coyote whose feet got burned -- on their Facebook page.