Some male bighorn sheep no longer grow large horns—possibly a result of human hunters’ natural selection.
Despite antipoaching patrols, increased arrests, relocation and unmanned security drones, it seems we’re losing the battle against wildlife poachers. Already in the first six months of 2013, for example, in South Africa alone, 428 rhinos have died at the hands of poachers. Rhino horns are in demand because the desire for traditional “medicines” in Asia is growing. Products that contain rhino horn are touted as successful cancer treatments, and rhino horn is being marketed even in hospitals to the families of critically ill patients
Other species, too, are suffering from specific human activities. A study published in the peer-reviewed journal PLOS One in March revealed that 62 percent of African forest elephants vanished between 2002 and 2011. The population is now less than 10 percent of its potential size. They are being poached out of existence for their ivory. The Wildlife Conservation Society estimates that some 25,000 African elephants are killed every year—this despite a ban on ivory poaching that was instituted in Africa in 1989.
Our efforts to counteract the devastating harm we’re causing to other species’ are failing. It looks like we humans need some help. And now, we just may be getting it from an unexpected source: evolution.
Eventually, all elephants may be born without tusks. ©Dave Luck
Elephants evolving
Luckily, we aren’t the only forces now trying to hold back the tide of poachers. The natural process of evolution is stepping in. According to an astounding research study recently published in the African Journal of Ecology, elephants all over the world have begun selecting against having tusks. For example, the frequency of female elephants without tusks has increased from 10.5 percent to 38.2 percent in South Luangwa National Park, Zambia. The tuskless trait appears to run in families and may have been a result of tuskless females being spared by poachers—tuskless mothers survive in greater numbers and hence have more tuskless daughters.
In Asia, there’s a similar trend. It used to be that only 2 to 5 percent of Asian male elephants were born without tusks. But by 2005, it was estimated that the tuskless population had risen to between 5 and 10 percent.
It’s clear that around the world, tusklessness is getting passed on. However, elephants use their tusks as weapons to battle during mating season and as tools to dig for water and roots. Nevertheless, it seems nature is recognizing that poachers are a greater threat to an elephant’s existence than its diminished ability to forage or to mate.
Rhino horns are prized in Asia for their purported “medicinal properties,” yet they contain nothing more than the same keratin found in fingernails. ©Toby Sinclair
Nature fighting back
A similar phenomenon is being seen with bighorn sheep. Trophy hunters aim for the animals that have the most impressive headgear. In recent years, however, according to a 1995 study published in Conservation Biology, males in some populations of bighorn sheep are no longer growing large horns. This may be a result of human hunters’ unnatural selection. But having no horns for sparring could cause problems, since males butt heads for dominance and to gain access to females. Apparently, trophy hunters are seen by nature as the bigger peril.
Evolution due to the influence of human hunting is also being seen in the fish world. Big cod are becoming more rare. Unlike most animal predators that go after the small and the sick, human fishermen try to catch the largest fish, those that are usually in their reproductive prime. This results in selective pressures that have driven cod and some other fish species to reach sexual maturity earlier and at smaller sizes.
And although we currently aren’t intentionally trying to overharvest cliff swallows, they, too, have been changing due to our actions. U.S. Department of Agriculture scientists estimate that 80 million birds die in collisions with motor vehicles in the United States every year. The swallows are now evolving to dodge vehicles.
Over the last three decades, the wing lengths of cliff swallows have been decreasing, making the birds more agile and better at avoiding cars. Autos may now be killing more long-winged birds.©Jordan Jones, flickr
Research results published in the publication Current Biology indicate that over the last 30 years, fewer cliff swallows have been killed along roads in southwestern Nebraska. At the same time, the birds’ wing lengths have been decreasing, allowing them to be more nimble and better able to dodge cars. The study’s authors suggest that automobiles may be killing higher numbers of long-winged birds, leaving more of the agile, nubbier-winged swallows to pass on their genes, circumventing the damage we do to this species with our cars.
Do you think that evolution has a fighting chance of being our last, best hope against poaching and the unintentional wildlife deaths we’re causing? Or will evolution simply take too long to save species already on the brink of extinction?
Here’s to finding your true places and natural habitats,
Candy
If you’d like to help in the effort to stop wildlife poaching, go to World Wildlife Fund’s Stop Wildlife Crime website.
To see elephants and rhinos in the wild, check out our African safari tours to countries such as Botswana, South Africa and Tanzania. To encounter Asian elephants, please take a look at our Asia adventure trips.
If someone thinks the poachers are their natural predators, by all means, call this ‘natural selection’.
However, IMHO, there isnt anything ‘natural’ about this. The poachers are causing the traits of tusks to disappear, because they’re literally killing off elephants with tusks before they’ve successfully had some offspring.
This is not a phenomenon. It’s Reality. This is just fast forwarding the evolutionary process where hunans in their lifetime can physically see how evolution works, by playing the part of the dumb predator that can’t seem to throw the little ones back in the see like every fisherman knows .
It is not surprising that we have become a primary evolutionary force for many species. I wonder to what degree it limits the options for species to adapt to other forces (like the need to compete for mates) and to what degree it is reversible when we ease the pressure. But I also wonder — if they no longer have tusks are they still really elephants? Or have they become something else? Anthrophants?
An interesting article commenting on a phenomenon that has been seen in a surprisingly large number of organisms worldwide, ranging from plants to animals. Mother Nature is fighting back – it’s time we fight back harder too.
Selective mortality factors such as poaching or trophy hunting for select physical features such as large tusks, antlers or manes may be considered a selective pressure, that over many many many generations could result in the selection of genotypes with tusk/antler/mane attributes less appealing to hunters/poachers. However, what is more likely being observed is just the proportional increase in individual animals “passed over” by the hunters/poachers. Chances are also more likely that elephants and rhinos will continue to be taken for their tusks/horns until the value of such items decreases below the cost of the effort required to hunt them. Given the outrageous black market prices, profit margins will remain lucrative into the future, or as is advocated here and elsewhere, an effective form of conservation/protection/regulation is implemented across the suitable range of elephants and rhinos. I do not see the same reasoning for bears or tigers other than the need for an effective form of conservation/protection/regulation.
Thank you Candy. All grist for the mill. 🙂
I agree with that statement: “If proper patrolling is done and sensitive entry points are blocked and trade is checked, it’s very affective in reducing poaching to large extent.” Well said, sir.
By the significant adaptation takes place, it’s likely the population is wiped out and it becomes extinct. What about tigers who are poached for their part. Efforts are not as enough to successfully help stop poaching and protect WL. Ther have been heavy poaching of tigers in Maharashtra state of India and since the new incumbent has joined since last year, it has tremendously increased which is clearly for lack of foot movement in the forests. The forest department has become an e mail nd SMS department only despite having al technology and enough vehicles for movement and other equipment. If proper patrolling is done and sensitive entry points are blocked and trade is checked, it’s very affective in reducing poaching to large extent.
Natural selection (in evolutionary theory) provides the mechanism for adaptive change. Heavy poaching pressure is likely to lead to local adaptation (If elephants with no tusks are the ones that survive, they will be the ones to pass on their genes/heritable traits to the next generation – then we will have tuskless elephants) at least in areas with heavy poaching pressure.
However, widespread elephant populations are likely to suffer varying degrees of poaching in different parts of their range. As a consequence, it’s most likely that we will see, given that any elephants survive, a number of sub-populations that differ slightly, or even considerably as far as tusklessness and tusk size.
Evolution or adaptation? More discovery seems in order.
It’s a pleasure to read something positive about poaching and wildlife! Interesting article. thank you
Hello; Human ignorance is one global problem which Mother Nature seems to be very close to curing. Of course; maybe Nature through evolution will enhance these targeted species with mental acuity; and physical adaptation to actively HUNT the humans who plague their respective species survival; NOW THAT WOULD BE A REMARKABLE EVOLUTIONARY SHIFT TO BALANCE THE FIELD ! 🙂
And I suppose that the next great hope is that wise old mother nature will evolve cats without skins and antelope that are not made out of meat.
Dear Candy, I wildly approve of your optimistic view and Nature will always outsmart us, but… this ‘solution’ simply takes too much time. And for the rhino’s there is almost no hope of solution, since poachers are being told to kill ALL rhino’s, also the one’s that had their horns removed by wildlife-rangers. The evil spirits behind this practice know that once rhino’s are extinct, the poached horns that are kept safely somewhere, will double or triple in value. Unfortunately, some people just stink too much to be corrected by evolution.
Very cool, timely article.
Great article. “Unnatural natural selection” is evolution. Selection of any kind is evolution.
I like the article but I wouldn’t really call what is happening evolution it’s more like unnatural natural selection. While the statement could be made that a fortunate side effect to elephant poaching it that despite all human efforts to seemingly destroy and annihilate this species the elephants continue to breed despite unfavorable characteristics, such as smaller tusks. This is great news because perhaps the smaller tusks will lead to less poaching or it could lead to more poaching due to the fact that more elephants with smaller tusks will need to be poached in order to meet demand. Not to mention the fact that elephants are not just killed for ivory but also because they can be viewed as a menace to locals, crops and villages. As long as human population pushes the boundaries and limits that its surrounding environment can sustain we will continue to push every other species toward extinction. Whether the competition is for food, water, space, territory or luxury items like medicine and ritual comforts. Interesting article though and I will keep hope alive that maybe the elephant and many other species will fight extinction and win.
….and humans are the top of the food chain! What does that say about humans?
Welcome to the Anthropocene!
Welcome to the Anthropocene indeed! What a great word by the way I will admit I had to look it up but I like it thank you for teaching me something wonderful…and awful at the same time.