How Dr Hsu Chia-Da investigates animal deaths at Singapore Zoo

An animal’s death can reveal a danger to others—or leave a difficult question unanswered. At Singapore Zoo, Mandai Wildlife Group veterinary pathologist Dr Hsu Chia-Da examines animals after death, with findings that can help veterinarians and keepers review care and watch for risks to surviving animals.5

How a post-mortem builds a picture

Dr Hsu’s work spans animals ranging from Nile hippos to insects. An examination begins with visible signs such as external injuries, then may move to the internal organs. Their appearance and tissue examined under a microscope can reveal changes that were difficult to detect while the animal was alive.56

Each finding has to be interpreted in context. An examination may show where bleeding occurred, for example, without proving exactly what caused the injury. Likewise, the absence of obvious signs of infection does not always rule infection out.6

Two turtles: a reason for caution, not proof of an outbreak

Two yellow-spotted river turtles were found dead within a week, raising concern about a possible disease outbreak. Dr Hsu cautioned that the timing alone did not establish infection. One turtle had remained in water overnight, and heat, decomposition and bacteria that multiplied after death made its original condition harder to interpret.56

He found no obvious trauma or signs of infection but could not definitively exclude infectious disease. The practical response was to watch the other animals in the enclosure more closely and seek veterinary assessment if they developed symptoms, including reduced appetite. In this case, an inconclusive post-mortem still informed a precaution.6

A python: evidence hidden inside the body

A rescued python had been bleeding from its mouth for days. Veterinarians suspected internal bleeding but could not determine its extent or cause while the snake was alive. After its condition worsened and it was euthanised, Dr Hsu found extensive haemorrhaging around its stomach, heart and lungs. His findings pointed to a possible impact around the stomach area, rather than establishing the exact circumstances of an injury.6

The contrast matters for future cases: a symptom visible in a living animal may reveal only part of what is happening internally. A post-mortem can give the veterinary team a fuller picture, though it cannot reconstruct every event with certainty.6

What a fatty liver finding can—and cannot—tell keepers

Fat accumulation in a reptile’s liver can make diet, body condition and activity important areas to investigate; reptile hepatic lipidosis has been associated with factors including obesity, poor diet and reduced activity.4 But a fatty liver finding alone does not establish which factor affected a particular turtle. The available reporting does not substantiate specific diet or activity changes made at Mandai in response to the turtle case.469

Dr Hsu’s work is ultimately a form of puzzle-solving in service of the living: CNA describes a decade spent looking for clues in animal deaths.7 The strongest lesson from these cases is not that every post-mortem delivers a definitive cause. It is that a carefully qualified finding can still direct monitoring, sharpen veterinary understanding and help keepers respond to potential risks.56 The available evidence does not establish particular specimen-preservation practices or contributions from these cases to a global zoo research network.