04/30/2008
They Deserve More Respect
A few weeks ago, I wrote about picking up the latest information from National Geographic’s Genographic project concerning my own DNA and the tracing of my paternal lineage back to a gentleman living in Africa between 39 and 70 thousand years ago. My DNA was studied via the Y chromosome, which is passed down via the fathers. Last week I read an Associated Press article in the April 25 Star-Ledger about research on mitochondrial DNA, which is passed down through mothers. You may have read or heard about the study, which came to the conclusion that we modern humans were close to becoming extinct about 70 thousand years ago.
The research, published in the American Journal of Human Genetics, was led by Doron Behar of Rambam Medical center in Israel and Saharon Rosset of IBM T.J. Watson Research Ccnter in Yorktown Heights, New York, and Tel Aviv University. Their team’s work indicates that climate changes in the form of severe droughts between 95 and 135 thousand years ago led to breaking up of the original modern human population into small groups that went their own ways. The researchers estimate that by 70 thousand years ago the total number of us modern humans was only about 2 thousand people. We could have been wiped had some rampant deadly viral or bacterial disease popped up.
Climate and/or the environment can markedly influence the evolutionary process. Even a plant related to the lowly dandelion evolved rather quickly to changing conditions, according to a very brief item in the May issue of Smithsonian. The plant, Crepis sancta, a weed with a flower that resembles a dandelion, sends some of its seeds into the wind while others just fall to the ground. In a French study in Montpellier, researchers, unidentified in the report, looked at C. sancta plants that lived in rural areas and those that found their way into the city in patches of dirt in the hostile paved city environment. They found that, compared to their country cousins, the city dwellers quickly evolved to have more of their seeds drop to the ground than go flying into the wind. It’s as though the plant realized it had better take advantage of the small amount of dirt surrounding it.
Sometimes it’s attitudes that evolve. The same issue of the Smithsonian magazine has an article by Steve Kemper titled “Who’s Laughing Now?”. The article is about hyenas, notably the spotted hyena. Hyenas, like the late Rodney Dangerfield, generally “don’t get no respect.” (For non-American readers, read this double negative as “don’t get any respect”.) I looked up the animal in my 1962 World Book Encyclopedia and found the following caption under a picture of a spotted hyena: “The spotted hyena of Africa is a skulking, cowardly animal, in spite of its powerful jaws. Its principal food is the flesh of animals killed by less timid beasts of prey.” Incidentally, the “laughing” is the sort of high-pitched cackling sound these animals emit when excited or frightened.
Kemper’s article deals with the work of biologist Kay Holekamp, who has spent 20 years studying spotted hyenas, and others, such as Jane Goodall, who found hyenas “second only to chimpanzees in fascination”. Various workers have found that, contrary to its scavenger image, spotted hyenas are skilled hunters on par with lions, cheetahs and leopards and kill 95 percent of their food. Back in the 1960s, biologist George Schaller found that in the Serengeti lions scavenged more food from hyena kills than did hyenas from lion kills. Lions apparently hate hyenas, however. It seems as though lions will go out of their way to kill a hyena but they don’t eat hyenas.
The hyena’s eating habits are rather unusual, to say the least, and probably account for some of the disgust with which the animal is held in the popular imagination. The spotted hyena’s jaws are formidable, able to crush just about anything. Holekamp’s description of the kill of a 400-pound zebra, one of the hyena’s favorite foods, is “awesome”, to use one of George Bush’s favorite words. The zebra will be polished off by a bunch of hyenas in less than half an hour, with the hyenas eating everything including bones, which they crush and pulverize, and even hair and hooves (regurgitated later). At the site of the zebra kill, all that is left, according to Holekamp, is a patch of blood.
Actually, that’s a pretty tidy meal. The fascinating, disgusting and surprising thing is that the hyenas do indeed scavenge in addition to killing their own prey. They will eat just about anything, including the most putrid, rotten, decaying meat of any kind. The fascinating thing is how do they get away with it? They obviously have immune systems to die for. Since I’ve been in my care giving role, I’ve been responsible for buying and preparing meals. A favorite lunch item is a sandwich with a local butcher’s veal loaf and other kinds of lunchmeat. With no preservatives, I’ve been surprised at how soon the meat becomes questionable as to its suitability for consumption. For a hyena this would be no problem and scientists would love to know the secret as to how hyenas manage to eat stuff that would sicken or kill virtually any other animal.
The Smithsonian article contains rather startling information concerning the female hyena’s anatomy but I’ll forego that, this being a family Web site. However, it should be noted that the hyena society is not one in which the males are the dominant sex; far from it. The females are not only bigger and more ferocious than the male hyenas, but they rule the roost with an iron hand. Each spotted hyena clan is ruled by an alpha female. When that zebra is killed the male must wait until the females and even the cubs have had their fill. Even if he kills his own zebra, the male has to gulp down all he can before the females shove him aside. The male really is the Rodney Dangerfield and “don’t get no respect”.
Another interesting thing about hyena society is that the mother spends a lot more time taking care of her offspring than other predators do. For three or four years the cubs are under their mother’s protection. Holekamp thinks this extended care period may be due to the massive bone-crushing jaws of the animal. It takes a number of years for the skull and jaws to develop and her theory is that the mother has to make sure her kids get enough food to allow them to get to the stage where they can strike out on their own. For that reason, Holekamp thinks that the females had to become “bigger and meaner”, becoming dominant and keeping the males in check.
I’m glad I’m not a male hyena. I’d much rather be what I am, a member of our male-dominated human society. Well, its time for me to do some laundry, shop for veal loaf and make lunch for my wife.
Allen F. Bortrum
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