Accompanying the first marchers was a giant banner, approximately 15 feet tall, that declared, "Harvard Tortures 1,500 Primates."

Many of the other marchers carried photographs of primates who appeared contorted, trapped in various metal contraptions. Several animals appeared to be prodded by metal objects. Organizers claimed that the photographs were given to them by a lab technician at MIT, though they did not provide any further documentation.

"World Week for Animals in Laboratories" will culminate on Sunday with a protest at the site of Harvard animal experiments in Southborough, about 30 miles from Cambridge.

ADLB began its push against Harvard-run labs on March 18, with a large Square rally that, according to organizers, attracted about 125 activists.

Both the lab in William James Hall and Harvard's New England Regional Primate Research Center (NERPRC) in Southborough have been vocally criticized by animal rights protestors for years.

"The NERPRC is causing great controversy in the Northeast... Vivisection labs are making billions and billions off torturing animals in the name of science," said protester Danielle M. Tessier, a Northeastern University senior.

"It's actually scientific fraud," she said.