The protest came following a week of public outcry after the release of shocking hidden-camera footage taken by a monkey caretaker who worked in the institute's labs.
Click here to see video on Let Animals Live website (Warning: contains disturbing images)
"I received emails, faxes and phone calls from decent, broken-hearted people who said they wanted to infiltrate the institute and free the monkeys from this hell, even if it would lead to their arrest, but I told them that we must remain within the boundaries of the law," said Anat Refua, spokesperson for Let Animals Live, which organized the rally.
"Our side abides by the law; it is those inside these walls who are the criminals. We will get the monkeys out of there legally," she added.
Using a loudspeaker, Refua and former Channel 2 news anchor Gadi Sukenik called on the Institute to end the experimentations "that do not contribute anything to modern science", as passing cars honked in support, indicating widespread sympathy for the cause.
According to Refua, the entire cast of the popular satirical TV show "Eretz Nehederet (Great Country)", who are currently shooting new episodes, asked that the demonstration be postponed so that they could also attend.
Some of the protestors went as far as likening the animals' suffering to the Holocaust, and wore black t-shirts bearing the words "For the animals, it is an eternal Treblinka" – a quote by Nobel laureate Isaac Bashevis Singer in "The Letter Writer".
Weizmann: Monkeys later rehabilitated
Reuven Ladiansky, legal counsel for Let Animals Live, said the group intends to file a request with the Rishon Lezion Magistrates' Court to issue an injunction against the Weizmann Institute and the National Council on Animal Experimentation, in accordance with the Animal Protection Law.
"Our request relates to all the different aspects of the cruelty involved in these experiments," Ladiansky said, "the monkeys, which are social animals that need contact with their own species, are kept in small cages, and during the actual experiments they are placed in a device that does allow them to even move their heads."
The organization also plans to file a complaint with Rehovot Police, claiming that the Institute is conducting cruel experiments in violation of the Animal Protection Law, an offense punishable by up to three years in prison.
"We are hoping that indictments will be filed," Ladiansky said.
Let Animals Live said four Knesset members - Eitan Cabel (Labor), Yoel Hasson (Kadima), Gideon Sa`ar (Likud) and Dov Khenin (Hadash) - are backing the organization's initiative and have called for a special Knesset session on the matter, scheduled for Wednesday.
The Weizmann Institute of Science issued a statement saying that it "abides by all laws of the State of Israel as well as international codes of ethics (including the National Research Council) in all matters pertaining to animal experimentation and welfare. This includes minimization of suffering and an extremely high standard of animal maintenance and care. The Institute will terminate, quickly and unconditionally, any research that does not meet even one of these regulations.
"Animal experimentation is crucial to understanding various biological processes. Such understanding frequently leads to the development of medical applications (drugs and therapies) that save human lives and improve the quality of life for millions," the institute said in a statement," the institute said.
According to the Weizmann Institute, the monkeys used in the research are rehabilitated and moved to a shelter in Ben Shemen.