3 monkeys still on the loose after truck overturns on Mississippi highway

People wearing protective clothing search along a highway in Heidelberg, Miss., on Wednesday, Oct. 29, 2025, near the site of an overturned truck that was carrying research monkeys. (AP Photo/Sophie Bates)

HEIDELBERG, Miss. (AP) — Three monkeys were still on the loose Wednesday in Mississippi after a truck carrying the research animals overturned, but it remained unclear who owns the monkeys, who was transporting them and where they were being taken.

The monkey mystery has left a host of unanswered questions for authorities.

Officials said at midday Tuesday that all but one of the escaped Rhesus monkeys had been killed. But the Jasper County Sheriff’s Department later said officials from Tulane University got into the trailer Tuesday evening and determined three monkeys had escaped.

Sheriff Randy Johnson said Tulane officials reported the monkeys were not infectious, despite initial reports from the truck's occupants warning that the monkeys were dangerous and harboring various diseases. But Johnson said in a statement that the monkeys still needed to be “neutralized” because of their aggressive nature.

The truck was carrying Rhesus monkeys, which typically weigh about 16 pounds (8 kilograms) and are among the most medically studied animals on the planet. The 21 monkeys on board had recently received checkups confirming that they were pathogen-free, Tulane said in a statement Wednesday. The university said it wasn’t transporting the monkeys and didn’t own them, but sent a team of animal experts to help with their care.

The monkeys were being housed at the Tulane University National Biomedical Research Center, which routinely provides primates to scientific research organizations, according to the New Orleans school. The research center is about 40 miles (65 kilometers) north of New Orleans in Covington, Louisiana.

Video from Tuesday shows monkeys crawling through tall grass on the side of Interstate 59 just north of Heidelberg, Mississippi, with wooden crates labeled “live animals” crumpled and strewn about.

The truck was no longer at the scene Wednesday, but people wearing white coats, gloves and hair nets were searching the area along with law officers.

University officials will be in the area looking for the missing monkeys, the sheriff said. All other monkeys were being transported back to Louisiana.

Dr. James Watson, Mississippi's state veterinarian, verified that the animals had the proper documents and “certificate of veterinary inspection” for legal transport across state lines, he said in an email to The Associated Press. The state's Board of Animal Health wasn't involved in the response to the crash, and additional information would need to come from Tulane's primate center, he said.

If anyone sees monkeys, they should call the authorities and shouldn't approach the animals, the sheriff’s office warned.

The Mississippi Highway Patrol said Wednesday that it was investigating the cause of the crash, which occurred about 100 miles (160 kilometers) from the state capital, Jackson.

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Associated Press Writer Jeff Martin in Atlanta contributed.