In some ways, Hiasl is like any other Viennese: He indulges a weakness for pastry, likes to paint and enjoys chilling out by watching TV.
But he doesn't care for coffee, and he isn't actually a person — at least not yet.
In a closely watched test case that could set a global legal precedent for granting basic rights to apes, Austrian animal rights advocates are waging an unusual court battle to get the 26-year-old male chimpanzee legally declared a "person."
Hiasl's supporters argue that he needs that status to become a legal entity who can receive donations and get a guardian to look out for his interests.
"Our main argument is that Hiasl is a person and has basic legal rights," said Eberhart Theuer, a lawyer leading the challenge on behalf of the Association Against Animal Factories, a Vienna animal rights group.
"We mean the right to life, the right to not be tortured, the right to freedom under certain conditions," Theuer said.
"We're not talking about the right to vote here."
The campaign was launched earlier this year after the animal sanctuary where Hiasl (pronounced HEE-zul) and another chimp, Rosi, have lived for the past 25 years went bankrupt.
Activists want to ensure the two apes don't wind up homeless if the shelter closes. Both have already suffered trauma: They were captured as babies in Sierra Leone in 1982 and smuggled in a crate to Austria for use in experiments at a pharmaceutical research laboratory. Customs officers intercepted the shipment and turned the chimps over to the shelter.
Their food and veterinary bills run about US$6,800 a month. Donors have offered to help, but there's a catch: Under Austrian law, only a person can receive personal donations.
Organizers could set up a foundation to collect cash for Hiasl, whose life expectancy in captivity is about 60 years. But without basic rights, they contend, he still could be sold to someone outside Austria, where he's now protected by strict animal cruelty laws.
"If we can get Hiasl declared a person, he would have the right to own property. Then, if people wanted to donate something to him, he'd have the right to receive it," said Theuer, who has vowed if necessary to take the case to the European Court of Human Rights in Strasbourg, France.
Austria isn't the only country where primate rights are being debated. Spain's parliament is considering a bill that would endorse the Great Ape Project, a Seattle-based international initiative to extend "fundamental moral and legal protections" to apes.
If Hiasl gets a guardian, "it will be the first time the species barrier will have been crossed for legal 'personhood,"' said Jan Creamer, chief executive of Animal Defenders International, which is working to end the use of primates in research.
Paula Stibbe, a Briton who teaches English in Vienna, petitioned a district court to be Hiasl's legal trustee. On April 24, Judge Barbara Bart rejected her request, ruling that Hiasl didn't meet the two key tests: He is neither mentally impaired nor in an emergency.
Although Bart expressed concern that awarding Hiasl a guardian could create the impression that animals essentially enjoy the same legal status as humans, she didn't rule that he could never be considered a person.
Martin Balluch, a scientist who heads the Association Against Animal Factories, since has asked a federal court for a ruling on the guardianship issue.
"Chimps share 99.4 percent of their DNA with humans," he said. "OK, they're not homo sapiens. But they're obviously also not things — the only other option the law provides."
Not all Austrian animal rights activists back the legal challenge. Michael Antolini, president of the local Society for the Prevention of Cruelty to Animals, said he thinks it's absurd.
"I'm not about to make myself look like a fool" by getting involved, said Antolini, who worries that chimpanzees eventually could gain broader rights, such as copyright protections on their photographs.
But Stibbe, who brings Hiasl sweets and yogurt and watches him draw, paint and clown around by dressing up in knee-high rubber Wellington boots, insists he deserves more legal rights "than bricks or apples or potatoes."
"He can be very playful but also thoughtful," she said. "Being with him is like playing with someone who can't talk."
A date for the appeal hasn't yet been set, but Hiasl's legal team already has lined up several expert witnesses. Theuer said they include Jane Goodall, the world's foremost observer of chimpanzee behavior, who revolutionized research on primates during the 1960s when she studied them at close range in Tanzania.
"When you see Hiasl, he really comes across as a person," Theuer said.
"He has a real personality. It strikes you immediately: This is an individual. You just have to look him in the eye to see that."