This past week proved to be an instrumental one for the protection of chimpanzees after the U.S. Fish and Wildlife Service proposed a new rule extending "endangered species" protections to chimpanzees that are also held in captivity.

Nearly half of all the 2,000 chimps in the U.S. that are held captive are then used for research purposes. The new proposed regulation would directly affect researchers as it will make it trickier to use chimpanzees for any type of medical experiments. The proposal is open to public comment for 60 days before it will be voted on.

However, researchers have known that this proposal was a long time coming. In the past decade or so, "there has been a significant shift away from using chimpanzees in research," says Kathleen Conlee, the vice president of animal research issues at the Humane Society of the United States.

Scientists first began running tests and analyzing chimps in the 1920s to gain insights into primate psychology - including, they hoped, the psychology of humans. Chimps share 98 percent of the same DNA as humans which has proved to be an integral part of early research on HIV, as well as to advances in the understanding and treatment of cancer and hepatitis.

As a result of being so close to humans, they have paid a high price by being poked and prodded with needles and electrodes, suffering illnesses with which they were infected. Many have died; others live with post-traumatic stress disorder. In recent years, the number of lab studies involving chimpanzees has dwindled as scientists instead studied genetically altered mice and rats or used new lab techniques.

In a blog post about the proposal, the director of U.S. Fish and Wildlife Service Daniel M. Ashe said "the chimpanzee is said to share 98 percent of our genes," he wrote.

"It is in our nature to protect and conserve this iconic species, and this proposal will help."

Researchers say populations of wild chimpanzees have fallen more than 65 per cent in the last 30 years because of poaching and loss of habitat.