Executive summary: A truck transporting rhesus monkeys overturned on a Mississippi highway on Tuesday, leading to the escape of the animals, with all but one killed and one still missing. Authorities have labeled the monkeys as aggressive but confirmed they are not infectious.
The accident occurred on Interstate 59 just north of Heidelberg, Mississippi, on the afternoon of October 28, 2025. Video evidence depicted monkeys moving through tall grass near the crash site, with damaged crates scattered around. The Jasper County Sheriff’s Department was quickly on the scene, warning the public about the aggressive behavior of the escaped primates.
The truck was carrying rhesus monkeys from the Tulane University National Biomedical Research Center in New Orleans, Louisiana. These animals, which typically weigh around 16 pounds, are among the most studied primates in medical research due to their genetic similarity to humans. They were being transported to another research organization, though specific details about the destination were not released.
Initially, the sheriff’s department posted on Facebook that the monkeys were carrying diseases, including herpes, and required personal protective equipment for handling. This raised alarms about potential health risks. However, Tulane University issued a statement clarifying that the monkeys are not infectious and do not pose a disease threat, working to correct the misinformation.
Law enforcement took action based on information from the truck driver that the monkeys were dangerous and posed a threat to humans. Most of the escaped monkeys were shot and killed, with only one remaining at large. Mississippi Wildlife and Fisheries joined the response, assisting in containment and search operations.
Rhesus macaques are known for their bold and curious nature, making them challenging to recapture. This incident recalls a similar event in November 2024 in South Carolina, where 43 monkeys escaped from a research facility but were all safely captured over time. Such escapes highlight the risks associated with transporting laboratory animals.
The cause of the truck overturning is still unknown, and it is unclear how many monkeys were in the vehicle initially. Authorities are investigating the crash while continuing the search for the missing monkey. Public advisories urge residents to report sightings but avoid contact due to the animal’s aggressiveness.
As efforts to locate the remaining monkey persist, the incident has sparked discussions on improving safety measures for animal transport in research. Collaboration between academic institutions and local agencies is crucial to address immediate concerns and prevent future occurrences.