One subject involves a 49-year-old, 6,500-pound hippopotamus.
Some day, you might smear gooey hippo sweat all over your body, and it won't be for a bizarre ritual or a television reality show.
You'll be using a sunscreen with the chemically manufactured sweat of a hippopotamus. Not only will it prevent sunburn, but it will ward off bugs and protect you from skin infection.
As creepy as it sounds, slippery hippo sweat could become the toast of the skin-care industry.
But before hippo sunscreen is hip -- or even invented -- science must unlock the secret of this massive mammal's secretions: What makes them work?
In that vein, research on hippo sweat marches forward at the University of California at Merced. Professor Christopher Viney soon will publish what could be a key study on the molecular structure of the secretions. He studied samples of the reddish fluid over the past year after locating the most logical sweat donor: Bulgy, the hippo at Fresno's Chaffee Zoo.
"Here's an animal that spends its whole life in a pool not getting sunburned," Viney says. "We can learn from nature."
From Bulgy's viewpoint, lounging at his zoo exhibit, donating the secretion was, well, no sweat. In fact, not much ruffles Bulgy, a mild-mannered, 6,500-pound specimen. He will be 50 in the next few months, making him one of the oldest hippos in captivity.
But a hippo can get pretty testy if someone invades his space and dabs his forehead in search of a sweat sample. It would be unwise to anger an animal weighing as much as three small SUVs, so Viney says he took no chances.
"Hippos are ferocious and territorial," says Viney, a University of Cambridge-educated engineer who specializes in bioengineering and material science. "The zookeepers at Chaffee hosed down his indoor enclosure and let him stand on the clean floor for a while. Droplets of his secretions fell to the floor."
It was not difficult to lure mellow Bulgy outside for a dip in his pool while Viney and his assistant, Amber Zielinski, 16, a Merced High School student, collected the droplets with special instruments.
Viney has examined the samples under a microscope. He has taken many photographs of the enlarged images in the microscope so he can see the way the secretion is formed.
"We need to understand the molecular organization in the secretion," Viney says.
Hippo secretion is not actually sweat; it's more like a mucus that helps cool the animal.
Zoo general curator Dale Thompson says Bulgy's sweat does not look like water or human perspiration. "It's more gelatinous," he says.
For some reason, flies don't seem to land on hippo sweat. It might repel bugs -- even mosquitoes, scientists say.
The sweat also seems to prevent infection. Hippos open gashes in the skin of other hippos during violent conflicts.
"Then they wallow in mud and other things," Viney says. "Hippos are not the cleanest animals, yet their injuries don't get infected. The suspicion is that the secretion is antiseptic."