Several rhesus macaques were killed by authorities in Mississippi after escaping from a crashed transport truck — but initial fears that the animals carried dangerous diseases may have been unfounded.
The accident occurred on October 28 in Jasper County when a truck carrying research monkeys from Tulane University overturned, allowing several of the animals to flee. The exact number of escapees remains unknown, but as of the latest update, three monkeys were still missing, according to the Jasper County Sheriff’s Department.
Early reports suggested that the monkeys were aggressive and infected with herpes, hepatitis C, or even COVID-19. However, Tulane University later clarified that none of the animals were carrying infectious agents.
“The primates involved belong to another organization and are not infectious,” Tulane wrote on X (formerly Twitter). “We are working closely with local authorities and have dispatched a team of animal care specialists to assist.”
The confusion appears to have stemmed from the truck driver, who warned deputies that the monkeys could pose a threat to humans and should only be handled while wearing protective gear. Acting on that information, officers took what they described as “necessary action” to contain the animals.
Sheriff Randy Johnson later told the Associated Press that the decision to “neutralize” the monkeys was made because of their reported aggressive behavior.
Are rhesus macaques dangerous?
Rhesus macaques (Macaca mulatta) are medium-sized primates that can become aggressive, particularly toward one another. Male macaques typically weigh around 17 pounds (7.7 kilograms), though the sheriff’s office initially estimated the escapees at around 40 pounds — likely an overstatement unless the animals were overweight.
In the wild, macaques can display fierce territorial behavior, often targeting faces, limbs, or eyes during fights. While they rarely attack humans unprovoked, those accustomed to people — especially in urban areas — sometimes lose their natural fear and may bite or steal food.
Captive macaques, such as those used in laboratories, can vary widely in temperament. Some are docile, while others become more aggressive due to stress, isolation, or improper handling. There have been no confirmed reports that the Mississippi escapees attacked anyone before being killed, and Tulane has reiterated that the animals had not been exposed to any pathogens.
Ongoing questions
It remains unclear who owned the monkeys, who was transporting them, and what their intended destination was. The Associated Press reported that investigators are still gathering details about the shipment and the research it was connected to.
Rhesus macaques are the most commonly used primate species in biomedical research and have played a major role in scientific advances, including the development of mRNA vaccines for COVID-19. Their use, however, remains controversial, with animal welfare advocates calling for stricter ethical standards and alternatives to live testing.
Not the first escape
Incidents involving escaped lab monkeys have occurred before. In 2020, macaques in India reportedly grabbed and ran off with COVID-19 blood samples after attacking a lab assistant. In another case, dozens of monkeys escaped from a South Carolina research facility.
There’s even a long-established wild population of rhesus macaques in Florida’s Silver Springs State Park — descendants of a few monkeys released in the 1930s by a boat captain hoping to attract tourists. He hadn’t realized that rhesus macaques can swim.
Now, decades later, their descendants still roam free — a reminder of how unpredictable human–animal interactions can become when research, transport, and nature collide.