Fragile X syndrome (FXS), formerly known as mental retardation, is a common developmental disorder with a prevalence of 1 in 3600 to 4000 males and 1 in 4000 to 6000 females (www.fragilex.org). Besides the intellectual challenges, patients often show behavioral abnormalities, which in a large part of the male patients strongly resembles autism-like behavior. Unfortunately, treatment of FXS is limited to the symptoms – think of behavioral therapy or pharmaceuticals to treat attentional deficits, anxiety, and impulse control problems.
Women and Venus, men and Mars, right? Men and women are fundamentally, biologically, and emotionally different. We also act differently in social situations. Wouter van den Berg and his colleagues at the Erasmus University Medical Center (Rotterdam, The Netherlands) recently published an interesting study that, using mice, shows the establishment of social hierarchies as being sex-dependent.
Why do wolves howl? From research, movies, and even television series, we learn that wolves cry out to each other to facilitate the reassembling of a pack when members have strayed. These calls are a functional way of long-distance communication, not only for wolves but also other species such as birds and mammals. So the functional importance of this behavior seems evident. But what actually makes a wolf cry? Is it because it misses its friends? Or is it simply something its body tells it to do?
Whether it’s an older sibling taking the last piece of cake from their younger sibling or a dominant coyote shoving a subordinate out of the way so it can eat the food, nature has its hierarchies. Generally, the stronger individual is at the top of the food chain – for example, the older sibling or the dominant coyote. Getting to the resource first doesn’t matter if you can’t defend the resource, as can be seen very well in the example of coyotes. Even if the subordinate coyote discovers the food source, the dominant will still monopolize the food there.
Dominant or subordinate?
Recently, a study was done by scientists in Millville, Utah, to investigate the effects of social hierarchy on the foraging efficiency of an individual. Eight pairs of coyotes (one male and one female in each pair) were observed in order to determine the effects of a dominant and subordinate being paired in the hunt for food. Before scientists could observe the coyotes, though, they had to determine which of the coyotes was dominant and which was subordinate. Winner-loser trials were used to test dominance, by letting the pair have a single food source and see which of the coyotes was displaced from the food.