Horseshoe crabs are often called living fossils. These primitive arthropods have lived on earth for 360 million years, largely in the same form as they appear today. Despite their long history, the horseshoe crab’s existence is now threatened by human activities, including harvesting for medical research.

Any time a foreign object or substance enters the human body, there’s a risk of introducing infection. If you’ve had a vaccination, a surgery of any kind, or had a medical device implanted in your body, you owe your very survival to the horseshoe crab.

Horseshoe crabs have copper-rich blood that appears to be striking blue in color. Proteins in the horseshoe crab’s blood cells are released in response to even the smallest amount of bacterial endotoxin (内毒素), such as E. coli. The presence of bacteria causes horseshoe crab blood to clot or gel, part of its hypersensitive immune response system.

In the 1960s, two researchers, Frederick Bang and Jack Levin, developed a method of using these coagulation (凝固) factors to test for contamination (污染) of medical devices. By the 1970s, their Limulus amebocyte lysate (LAL) test was being used commercially to make sure everything from scalpels (手术刀) to artificial hips (髋关节) is safe for introduction in the human body.

While such testing is crucial to safe medical treatments, the practice takes a toll on horseshoe crab populations. Horseshoe crab blood is in high demand, and the medical testing industry catches as many as 500,000 horseshoe crabs each year to drain them of their blood. The crabs aren’t killed outright in the process; they’re caught, bled, and released. But biologists suspect the stress results in a percentage of the released horseshoe crabs dying once back in the water. Fortunately, management practices are in place now to protect the species.

In addition to their value in medical research, horseshoe crabs fill important ecological roles. Their smooth, wide shells provide the perfect substrate (基质) for many other marine organisms to live on. As it moves along the ocean’s bottom, a horseshoe crab may be carrying mussels, barnacles, tube worms, sea lettuce, sponges, and even oysters. Horseshoe crabs deposit their eggs by the thousands along sandy shorelines, and many migratory shorebirds, including red knots, rely on these eggs as a source of fuel during their long flights.

Mice are used in lab tests all over the world. But why should they suffer this pain?

In the United States alone, more than 100 million lab mice are killed every year. Some of them are slowly poisoned (毒害) to death. Some are placed on hot plates, heated to 60 ℃, to see how long it takes for them to respond to the heat. Some are given deadly diseases. Some have holes drilled into their skulls (头盖骨) for brain experiments. And in some experiments, mice's tails are cut off without painkillers.

Mice are mammals (哺乳动物).They have nervous systems similar to ours. They also feel pain, fear and loneliness — just as we do. Mice are social animals. They also love their families. They “talk” with each other using sounds that the human ear cannot hear.

Although lab mice suffer as much as lab dogs and lab cats, they are not given as much protection as the dogs and the cats are. Labs can use as many mice as they want to. They don’t even have to count the mice they kill. Few of them are looking for modern alternatives.

Perhaps you can help make a difference. Do not support companies that test on mice or other animals. You can let more people know the facts about lab mice by setting up open classes in your neighborhood. Also, you can ask the local labs to think twice before doing experiments using mice.

Humans have always assumed that there is a huge gulf between animal behavior and human development. However, recent research into animals shows that animals are continuously designing innovative methods to finish their tasks. Examining the nature and results of their creativity can help us understand evolution.

Research shows that animals too can be creative. By inventing new behavioral patterns and adjusting their behavior to new contexts, as well as to changes in social and ecological environments, researchers show that animal innovation too can be diverse. For instance, chimpanzees (猩猩) use tools such as sharp spines and stalks to remove the hearts of palm vegetables from trees. Herring gulls (鲜鱼海鸥) found out quite a cruel way of killing rabbits-drowning them in the sea.

Innovative species tend to survive when they enter new places, but novel behavior cannot be recognized unless “normal” behavior is studied. Researchers can now count and document the innovations that have been created by species, which would help them to quantify their creativity. Studies also show us that all animals are not equally inventive, with primates (灵长目动物) tending to be more innovative due to their bigger brains.

The greatest scientific significance has been the innovation shown by animals such as apes, capuchins and macaques among primates. These species of primates possess the biggest brains in proportion to their body sizes. They are also heavy tool users. Their broad diets and complex forms of learning are also insightful. They indicate an evolutionary strategy that gave them new solutions to life’s challenges.

However, even if these animals show innovativeness, they do not have the ability to improve upon solutions of others. Unless they share information accurately and copy each other’s inventions. their creative inventions are likely to vanish before they can be innovated further. This ability can be managed only by humans, for we are able to build on shared knowledge.