Beefalo or buffalo? The purebred push for bison

July was National Bison Month — but not at the Denver Zoo, which set four of the burly brown beasts free earlier this year. Well, not exactly free: If you think coyotes are a pain, just imagine what a couple of buffalo would do to back yards in Centennial.

No, in January the zoo sent its four critters — one bull and three cows — to the Last Gulch Ranch in southeastern Colorado, where they are living with forty other bison owned by conservationist rancher Robert Alsobrook. The beasts needed to go to help make room for Asian Tropics, a ten-acre, $50 million elephant exhibit now under construction at the zoo ("Caution, Elephants Coming," July 9, 2009). But the zoo still owns the bison and plans to build a herd of purebred animals on the ranch so it can study how they interact with the environment compared to bison that have been interbred with cattle, says Rich Reading, conservation biology director at the zoo.

Although there are more than half a million bison in the United States, only a small portion of them are genetically pure — including the four zoo animals, the two herds owned by the City of Denver, and the famous animals at Yellowstone National Park. "Bison are a keystone species," Reading says, meaning that their habits, particularly their grazing patterns, can affect living things all around them, including plants, birds and small reptiles and amphibians. And purebred bison graze differently than beefalos.

As a result, they also taste different than meat from beefalos. Reading believes bison meat could be a real specialty for ranchers, since it's leaner than beef. "You lose some of that leanness with cows," he explains. "We're hoping to convince bison ranchers like Robert to slowly shift from mixed-breed to purebred bison."

Getting started wasn't easy, though.

When the zoo's four animals first arrived at Last Gulch, Alsobrook kept them in a separate corral so that they could acclimate to their surroundings. "My buffalo would come up and visit them, and the zoo animals would run back and forth because they wanted to go out there and join them," he recalls. "But after one or two laps, I noticed their tongues were hanging out. Alsobrook thought the animals were dehydrated and checked their water, but eventually he realized that they were just out of shape from having lived in the zoo's pens (apparently cotton candy and popcorn aren't good for bison, either).

When he finally opened the corral, the zoo's bull "rushed out and fought my bull right away," Alsobrook says. "It lasted about ten seconds, and that zoo bull got his butt whipped. He had never used so many muscles in his life."

The zoo bull might have been pampered, but he was no pushover. He kept getting back up to fight, and within a week, he'd bested Alsobrook's bull and taken over the herd. "Now he's nothing but muscle," the rancher says.

Muscle and testosterone. Despite the fact that the zoo bull has been fixed, the manly animal thinks he can still reproduce. So he'll either be castrated or separated from the herd so that the other purebred bull — which Alsobrook bought from Denver's Genesee herd — can get busy making little purebreds.

Scene and herd: Emily Osment, the seventeen-year-old co-star of Hannah Montana, may have fame, half a million Twitter followers and an album coming out this month, but the Disney diva is also still a teenager. So after performing at Elitch Gardens last Saturday, she and the band Allstar Weekend mingled with the crowd and hit the rides (with a security guard), including a spin on Twister II.

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