Stories tagged behavior

Nov
10
2009

Curious langur
Curious langurCourtesy John Downer
Have you ever wondered why people honk at you .02 seconds after the light turns green? Or why some people take Connect Four a little too seriously? Well, it may be the length of their fingers. That’s right, the difference in length between your 2nd finger (or pointer finger) and your 4th finger (or ring finger) is thought to be an indirect measurement of testosterone levels you were exposed to during fetal development. The more testosterone, the longer your ring finger compared to you pointer finger.

In a recent study, researchers from the University of Liverpool and Oxford used this measurement to link aggressiveness in primates with the levels of prenatal testosterone in utero. They found that Old World monkeys tended to have a low 4th digit (4D) to 2nd digit (2D) ratio (i.e. their ring fingers were longer than their pointer fingers) and also exhibited aggressive, competitive, and promiscuous behavior. New World monkeys (like gibbons), on the other hand, along with Great Apes (like chimps and orangutans) tended to have a higher 2D:4D ratio. These species were found to exhibit much more cooperative and tolerant behavior. The results of the study have implications for our own social behaviors. We live in large multi-male, multi-female groups and are (usually) quite cooperative. This study, and more like it, could start to shed light on the origins of our sociality.

The use of digit ratio as a measurement of prenatal testosterone is not new, however. Many researchers have used it even in humans (we are primates after all) to try and predict various behaviors, aptitudes, and personal characteristics. For example, some of the traits suggested to correlate with low digit ratios (ring longer than pointer) include greater male fertility, assertiveness in women, and greater musical and athletic ability. These studies looked at the increased competitive nature brought out in individuals with exposure to high levels of prenatal testosterone.

So the next time someone cuts you off, just know it might be the case that their 4th digit is longer than their 2nd… so try to leave your 3rd digit out of it.

Oct
21
2007

It knows when you are sleeping; it knows when you're awake: And it knows what you've been thinking.  (Image courtesy of Wikimedia Commons)
It knows when you are sleeping; it knows when you're awake: And it knows what you've been thinking. (Image courtesy of Wikimedia Commons)
Like Santa, elephants totally know if you’ve been bad or good

The “bad or good” value judgment depends on whether or not you plan on killing them. “Them” being the elephants, of course, not Santa. No one should plan on killing Santa. He would know what you were up to if you planned it.

People do occasionally plan on killing elephants, however, which is presumably why they have gotten good at telling who these people are. New research shows that African elephants are often able to distinguish, through sight and smell, between humans who are a potential threat and those who are generally harmless.

For the purpose of the study, scientists from the University of St. Andrews compared the reaction of elephants from Amboseli National Park in Kenya to people from the nearby Maasai and Kamba tribes. While Kamba will generally only attack elephants when they invade their farmland, Maasai will occasionally spear elephants as a show of virility. It has been observed that elephants will become defensive or run away as Maasai approach, even when they are still several kilometers away.

The Kamba and Maasai are fairly distinct as to their diets and dress. The Maasai traditionally wear red shawls; the Kamba do not. The Maasai eat lots of milk, and sometimes cattle blood and beef, whereas the Kamba eat plenty of vegetables and maize, and some meat. Scientists believed that this difference in diet could be apparent to an elephant’s sensitive sense of smell.

To test the elephants’ sight reactions, the scientists displayed clean and unworn pieces of white cloth and red cloth on bushes in Amboseli. They found that the animals acted “significantly more aggressively toward the red cloths.” This is one of the more obvious points at which elephants and Santa diverge in their behavior – we all know that Santa has an almost perverse attraction to red cloth.

The St. Andrews researchers then presented elephants with clothing that had been worn for five days by either a Maasai or Kamba man. The elephants seemed to react with greater fear towards the clothing worn by Maasai men, running faster and further away from it, and towards tall grass for cover. Also, according to the researchers, these elephants took significantly longer to relax after they stopped running.

When the same experiments were repeated on Santa, scientists observed that he behaved in a similar fashion, running and hiding from some pieces of clothing but not others. Santa’s reactions of fear, however, appeared to correspond to the clothing of particular individuals, not to that of entire groups. Researchers were denied access to the famous “lists,” unfortunately, and so were unable to crosscheck for specific names. When asked how they intended to continue their research on Santa, the scientists enigmatically replied, “We have no plans.”