In a zoo, a crisis often begins before anyone names it as such. An animal stops responding to treatment. A pregnancy fails to progress. A procedure goes as planned, yet recovery does not follow. The work is technical and uncertain, and the margin for error is narrow. Outcomes depend on biology, timing, judgment, and factors that are not immediately apparent.
Don Janssen, a wildlife veterinarian who spent more than three decades at the San Diego Zoo and its Safari Park, came to see his profession through this lens. Early in his training, he assumed that liking animals more than people would be an advantage. A senior veterinarian corrected him: without learning to work well with people, conflict would follow, and the animals would bear the cost. Janssen returned to that lesson often.
After graduating from the University of California, Davis in 1978, he built a career that helped shape modern zoological medicine. At San Diego, he rose to director of veterinary services and later vice-president of animal health. His work ranged from routine care to complex interventions involving endangered species, often requiring coordination across institutions. In one widely recalled case, a young orangutan survived a demanding period of post-operative care through the combined efforts of dozens of specialists and volunteers. Janssen saw such episodes less as triumphs of technique than of cooperation.
Colleagues described him as measured and attentive, not inclined to assert authority for its own sake. He listened closely and made time. He wrote frequently about “servant leadership,” though in practice it meant habits: building trust before problems arose, clarifying roles, and staying present when things went wrong. In one account of a failed treatment, he recalled a manager who arrived late at night simply to stand with the team. From that, Janssen drew a principle he repeated: in a crisis, attend to the people first.
Later in life, he was diagnosed with Parkinson’s disease. He wrote about it without sentimentality, seeing it as a reminder that control is limited and response matters more. He died last week, aged 73.
His work left few simple markers in the animals he treated. Its influence was clearer in the people he trained and the habits he encouraged.
Full obituary: Don Janssen, wildlife veterinarian who argued that caring for animals begins with people
Correction (4/27/26): The original version of this piece said Janssen died at age 70. He was 73.
