CHICAGO - In April 2005, Mumbali, an adolescent female gorilla, was dying of a mysterious infection at Lincoln Park Zoo.
In a last-ditch effort to save her life, veterinarians and keepers anesthetized both Mumbali and Kwan, a male gorilla, then laid them side by side to send Kwan's blood directly from his arm into hers.
It was a crude procedure, similar to the way transfusions were done for humans before the blood bank was invented at Cook County Hospital in 1937.
But there was little to go on in the veterinary literature, which had nothing about whether gorillas have different A-B-O blood groups as humans do, or if they needed to have blood matched to their own for a successful transfusion.
"It's one of the most basic pieces of knowledge we need for the care of our animals, and it simply wasn't there," ape keeper Jill Moyse said.
Mumbali died despite their emergency interventions. Afterward, as keepers and veterinarians met to grieve her passing, Moyse told them Mumbali's death "could only make sense if we can make something good come out of it."
Five years after that impromptu discussion, Moyse and Kathryn Gamble, the zoo's chief veterinarian, have created a new body of literature on great-ape hematology. Just as important, they have produced an international registry to record the blood types of captive apes on four continents.
The registry represents all four great ape species - gorillas, orangutans, chimpanzees and bonobos, which are sometimes called "pygmy chimps." In North America, it encompasses nearly every healthy male and female adult of the species who could donate blood if another ape of its species with the same blood type needed a transfusion.
"You don't want to transfuse the wrong type of blood, because a transfusion reaction can make a bad situation even worse," said Gamble, who recently published the research in the journal Zoo Biology. "These are small populations," she said, "so emergency calls for blood are pretty rare. But when you need it, you really, desperately need it."
Before the project began, the only species of great apes with known blood groups were chimpanzees, the majority of which have Type A blood. That is known because chimps are frequently used as stand-ins for humans in medical research.
The project has verified that the blood of different ape species isn't interchangeable between species or humans, she said. It found that bonobos have only Type A blood, while orangutans have all four types, A, B, AB and O.
"Gorillas so far are somewhat confusing and frustrating," said Gamble. "Although all of their cards came back as Type O, it is clear from genetic evaluation from our collaborators at University of Chicago that gorillas don't in fact have all the same blood type."