Research monkeys got loose after a truck overturned on a highway. Their owner, destination, and exact purpose remain shrouded in mystery

Three monkeys have remained at large since the incident Tuesday in a rural area along Interstate 59, resulting in wooden boxes labeled “Live Monkeys” being spilled onto the tall grass near the highway. Since then, researchers wearing masks, face shields and other protective gear have searched nearby fields and forests for the missing primates. Five of the 21 rhesus macaques on board were killed during the search, according to the local mayor, but it was not clear how that happened.

Key details remain shrouded in secrecy

Mississippi state authorities did not reveal the company involved in transporting the monkeys, where the monkeys were headed, or who owned them. While Tulane University in New Orleans acknowledged that the monkeys were housed at its National Biomedical Research Center in Covington, Louisiana, it said it did not own them and would not identify who owned them.

An initial report from the sheriff described the monkeys as “aggressive” and carrying diseases such as herpes, adding to the confusion. Tulane later said the monkeys were free of pathogens, but it remains unclear what type of research the monkeys were used for.

Animal rights advocates say the questions surrounding the Mississippi crash and the mystery of why the animals traveled through the South are eye-opening.

“When a truck carrying 21 monkeys crashes on a public highway, the community has a right to know who owns those animals, where they have been sent, and what diseases they may have been exposed to or harbored simply because of their involvement in the primate experimentation industry,” said Lisa Jones Engel, senior scientific advisor for primate experiments with People for the Ethical Treatment of Animals.

“It is highly unusual — and deeply troubling — for Tulane to refuse to identify her accomplice in this shipment,” Jones-Engel added.

The only thing known is that the 2025 Chevrolet Silverado truck transporting the monkeys was being driven by a 54-year-old Maryland man when it veered off the highway into the grassy median area, the Mississippi Highway Patrol said in a statement to The Associated Press. Neither the driver nor his passenger, a 34-year-old resident of Thurmont, Maryland, was injured.

Confidentiality is included in contracts, withholding information

Tulane University said in a statement to the Associated Press that transporting research animals typically requires legally binding contracts that prohibit the parties involved from disclosing information. The New Orleans-based university said this was done for the safety of the animals and to protect proprietary information.

“To Tulane’s knowledge, the 13 recovered animals remain in their owner’s possession and are on their way to their original destination,” the statement read.

The incident has sparked a range of reactions – from conspiracy theories suggesting a government plot to make people sick, to serious reactions from people who oppose animal testing.

Republican US Representative Marjorie Taylor Greene said of the incident: “How sad and so wrong.”

“I have never met taxpayers who want their hard-earned money to pay for animal abuse nor those who support it,” the Georgia congresswoman said in a post on the social platform X. “This must end!”

The Tulane Center has relationships with more than 155 institutions around the world

The Tulane Covington Center receives $35 million annually in NIH support, and its partners include nearly 500 investigators from more than 155 institutions globally, the school said in an Oct. 9 news release. The center has been funded by the National Institutes of Health since 1964, and federal grants have been an important source of income for the institution, she added.

In July, some of the research center’s 350 employees held a ribbon-cutting ceremony to mark the opening of a new 10,000-square-foot office building and new laboratory at the facility. This fall, the facility’s name was changed from the Tulane National Primate Research Center to the Tulane National Center for Biomedical Research, to reflect its broader mission, university officials announced.

Research monkeys have escaped before in South Carolina and Pennsylvania

The Mississippi incident is one of at least three major monkey escapes in the United States in the past four years.

Last November, 43 rhesus macaques escaped from a complex in South Carolina that raises them for medical research after their enclosure was not completely sealed. Employees of the Alpha Genesis facility in Yemassee, South Carolina, set traps to catch them. However, some spent two months that winter in the forest and survived a rare snowstorm. By late January, the last four escapees were captured after being returned to captivity with peanut butter and jelly sandwiches.

In January 2022, several cynomolgus macaques escaped when a truck pulling a trailer containing about 100 animals collided with a dump truck on a Pennsylvania highway, authorities said. Authorities said the monkeys headed to a quarantine facility at an undisclosed location after arriving at John F. Kennedy International Airport in New York on a flight from Mauritius, an island in the Indian Ocean. A spokesperson for the Centers for Disease Control and Prevention said all of the animals were found within about a day, though three were euthanized for undisclosed reasons.