Invasive knotweed helps heal Franklin Park Zoo's giraffe

By 
Daria Casinelli
May. 14, 2008

To feed a finicky giraffe with wasting disease, you need the right food and plenty of it. Beech leaves might be Franklin Zoo denizen Beau the giraffe's absolute favorite, but an invasive plant in Franklin Park called Japanese knotweed turns out to be a close second.

According to Pearl Yusuf, Assistant curator for hoofs and horns at the Franklin Park Zoo, volunteers from the Franklin Park Coalition (FPC) are helping the giant ruminant get enough of his second favorite food to save him from giraffe wasting syndrome.

"They have it and we need it," said Yusuf.

Beau's guardians, who once cut fresh browse daily for their picky eater, ran into volunteers from FPC's weed-cutting crews in the same patch of knotweed, according to FPC director Christine Poff. The FPC is battling the knotweed, considered an invasive scourge that is well entrenched in the parks lowlands and making inroads into the higher elevations.

"Peracute mortality syndrome," or giraffe wasting syndrome, is common among giraffes, usually fatal, and poorly understood. One of the things known about the disease is papillae, the tiny finger-like projections inside the animal's gut that absorb nutrients, begin to degrade and shrink. This can set off a chain reaction resulting in unstoppable weight loss. At his worst point, Beau was down to 1,700 pounds and one very sick critter.

The day I met Yusuf, Beau's beautiful head floated down to sniff her as if to say, 'Yeah, that's you.' Then he did that wacky stilt walk to the other side of the giraffes' private pen. Something about a giraffe is like an insect, spindly and delicate; it saunters no matter how fast it's actually moving. Masai giraffes like Beau have been known to kill a lion, but they can't leave their stall if the temperature goes below 65 degrees. And they don't like change, especially in their food.

One of the challenges, according to Yusuf, of treating a giraffe with wasting syndrome is Beau was fine with eating his alfalfa grain concentrate day after day, but that feed wasn't absorbed easily. He was a stolid, boring feeder and he ate a lot, but he was still losing weight. As they worked for over a year to find something he would eat and gain weight with, Yusuf and her colleagues had to figure out if Beau wouldn't eat new foods because he didn't like them, or simply because they were new.

Japanese knotweed is so relentlessly prolific that in 1981 the U.K. it made it illegal to spread it with the Wildlife and Countryside Act. It has to be disposed of in lined landfills and construction sites need a certificate saying they've handled it properly. It's listed by the World Conservation Union as one of the world's 100 worst invasive species. According to Allen Ihrer, FPC volunteer and invasive plant autodidact, "if it's let go, in 10-20 years it will take over a significant part of the park. About the only things that eats it, besides Japanese beetles, are gorillas and giraffes."

The gorillas' keepers are also thinking of harvesting the pernicious invader for their wards, said Yusuf. To zookeepers, the invasive plant's ubiquity is a boon.

Yusuf said that any tough fibrous vegetation would give Beau's digestive system the necessary work out and that a beet pulp specially concocted by the zoo staff is also helping a lot. But because he's a ruminant Beau needs to eat constantly and that means they need to provide him with very large quantities of roughage. What's special about Japanese knotweed is that Beau loves it so much he'll eat it most of the time. The knotweed and beet pulp have allowed Beau's weight to soar to 2,600 lbs. At ten years old he's lived for three years with a disease that kills most giraffes in a year. This is good not just for Beau and the people who love him, but for the species as a whole. Beau is so healthy that he has fathered two calves making him an important part of the zoo's breeding program.

Six-month-old Sox the baby giraffe, Beau's second offspring, will meet her adoring fans any day now. Yusuf said that she needed to meet the zebras with whom she will be sharing the main pen before her official debut, because she'd never met a zebra, and you just never know what might happen. As of this writing, Sox had just started eating solid foods, including the beet pulp created by the Franklin Park Zoo's staff. When asked if Sox would eat Japanese knotweed, Yusuf said, "I hope so."