Thursday, December 11, 2014

How human are chimps? The differences and similarities between chimpanzees and humans.

The state of New York recently ruled that chimpanzees are not entitled to the same privileges and rights as humans. Chimpanzees have long given humans plenty to think about when it comes to defining what exactly is human. Jane Goodall, when she observed chimpanzees using tools in the wild stated, "Now we must redefine tool, redefine Man, or accept chimpanzees as humans." I decided to look at some of the ways chimps are just like us and some of the ways they're not at all like humans.
Young chimpanzee. Photo credit Sabine Bresser

Like humans:

1. Chimps taken from their mother at a young age suffer long-lasting behavioral consequences. Specifically, chimps raised by humans rather than other chimps groom each other less frequently than chimps raised by their chimpanzee mothers, and they also engage in sexual behaviors less frequently. Read the study done by Freeman and Ross at the Lincoln Park Zoo here. Looks like each species should probably raise its own young.

2. Chimps can cooperate and do so spontaneously. In a study where chimpanzees were given access to a task in a larger outdoor area, as opposed to a small, controlled area where most testing typically occurs, chimpanzees had the choice to use the apparatus and try the task or avoid it entirely. Surprise! Chimpanzees chose to use the apparatus, which required cooperation and choosing a partner chimpanzee to achieve the task, meaning chimps don't just work together when there's nothing better to do. These chimps sought cooperation out. Check out the article by Suchak and others here.

3. Chimps display different cultures, as shown by separate populations of chimpanzees using tools in different ways despite seemingly the same ecological conditions. A 2010 study examined how two populations obtain honey (a real treat for a chimpanzee) and found one population using sticks while another used wedges of leaves to soak up the delicious and highly coveted food item.

Unlike humans:

Photo credit Sergio Morchon
1. Chimpanzees may be able to communicate, but they have yet to display a mastering of complex language and grammar. While yes, chimps and other apes have a grasp of sign language and some even use computers and symbols to communicate with humans, are they capable of knowing the difference between sentences such as, "I bit the dog" and "The dog bit me?" The answer appears to be no. For a great film that I highly recommend, watch Project Nim. It's thought-provoking, heartbreaking, informative, and definitely worth a watch if you're interested in language or even more broadly interested in chimps.

2. Chimpanzees don't teach their young. Now, this might be a somewhat controversial claim since teaching in animals is hard to study (how do you determine if one it is one individual's intent to share knowledge with another?). Chimps certainly learn by watching other chimps and new behaviors are socially transmitted, but does one chimpanzee purposefully and knowingly teach another? Even if you disagree with me, you must admit that humans take teaching to a new level. With our creation of schools and our ability to guide and help others in a hands-on way, we take teaching to a level definitely not seen in chimps.

3. Finally, chimpanzees are not nearly as adaptive as humans when it comes to geography. Homo sapiens, or humans as we know and love ourselves today, weren't even the first to leave Africa and travel to other continents. Our earlier humans ancestors did that first, but the fact remains, humans love to travel. We have blogs dedicated to traveling, the desire to know what's just over that mountain or on the other side of the lake. We seemingly need to go everywhere and we're on every continent if you include the research done in Antarctica. We've adapted to all of these different climates through tools and clothing and behavioral adaptations. I don't think anyone can argue chimps have caught the travel bug quite like humans have.

Food for thought: Does learning these facts about chimps change the way you view what it means to be human? What is the most important difference between chimps and humans? What is the most important similarity?

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