Elephants Evolve Smaller Tusks Due to Poaching
Sun, Jan 20, 2008
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A species’ evolution has long been thought to take thousands of years to produce seemingly minor changes.
It appears that in at least one case, however, evolution is occurring at what seems like jet speed. In the last 150 years, the world’s elephant population has evolved much smaller tusks.
The average size of an African elephant’s tusks has gone down by half in the last century and a half. Indian elephants have undergone a similar tusk size reduction.
Experts believe the rapid evolution of the massive land mammals is due to poaching. Zoologists from Oxford University suggest that ivory poachers, who go for the largest males with the largest tusks, have caused the breeding behaviors of the animals to change rapidly in a short time.
The largest male African elephants have the largest tusks. These tusks are extremely important in elephant behavior, with the largest tusks usually resulting in more successful intimidation of smaller males or winning fights for female elephants. But when the largest animals are killed, it changes the breeding patterns of the animals. In short, without the largest males for competition, the smaller males with their smaller tusks will breed more successfully, and their offspring will have smaller tusks.
Study co-author Iain Douglas Hamilton of Save the Elephants said in the Telegraph: “What appears to be the case is that average tusk sizes have decreased greatly since the mid-19th century. The data comes from the trade statistics and from records of hunters around Africa who find that large trophies are very much harder to find. While some of this may be due to an absence of older animals, it is possible there has been a genetic selection pressure against large tusk size that outweighs their usefulness in contests with other males in winning females.”
Source: Telegraph
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The Guild of Scientific Troubadours » Elephants evolve smaller tusks. Says:
January 24th, 2008 at 8:08 am[...] findings of Iain Douglas Hamilton and his colleagues, who appear to have discovered evidence that elephants are evolving smaller tusks due to ivory poaching: In the last 150 years, the world’s elephant population has evolved much smaller [...]
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The Mystery of the Murdered Sea Mammals : Environmental News Blog | Environment News | Environmental Graffiti Says:
January 29th, 2008 at 4:24 pm[...] land and almost no fear of humans. The carnivorous species is an important part of the island’s ecology, and any harm done to their population could threaten the fragile environment and animal diversity [...]
January 21st, 2008 at 1:13 am
those darn poachers!
January 21st, 2008 at 5:22 pm
It’s natural selection. The elephants with larger tusks are being exterminated by poachers, thus the only ones left to breed are the elephants with smaller tusks. Those “smaller tusk genes” are then spread to the next generation of elephants. It’s not like evolution is speeding up, elephants are just breeding with the only possible mates left and those genes are passed on.
January 21st, 2008 at 9:20 pm
Natural Selection is part of the Theory of Evolution. There are two major components to Evolution, Natural Selection and Mutation. Evolutionary process is speeding up in many cases. If the species survives human forced near extinction, it will most likely be to highly accelerated Natural Selection as a part of Evolution.
January 21st, 2008 at 9:49 pm
Mistere, all evolution is selection of some sort. Selection promoted by the desire of poachers is not natural. The presented case of larger-tusked males intimidating smaller ones and thus successfully breeding is natural. Evolution is a change from one state to another. The state of average tusk size for the general population of elephants is decreasing rapidly, therefore evolution has been sped up by the interference of man.
January 22nd, 2008 at 12:26 am
“Selection promoted by the desire of poachers is not natural.”
I have to disagree with that. Man is part of nature — the pressure applied by the poaching is no different than any other environmental pressure. In no way do I mean to imply that poaching is right. Merely that man is just as much a part of nature as the rest of the planet.
January 22nd, 2008 at 5:19 pm
While human intentions maybe ‘unnatural’, our actions become part of a larger process a process that for now remains ‘natural’.
I don’t believe there is an inverse to Natural Selection ie: Unnatural Selection, just as there is no inverse to The Uncertainty Principal ie: The Certainty Principal.
January 22nd, 2008 at 5:33 pm
Yeah I suppose you’re right. I didn’t disagree that it was evolution, just the idea that it’s “speeding up,” per se. The way you put it makes sense though.
January 22nd, 2008 at 9:36 pm
Some clarifications of the discussion of evolution here:
1) Not all evolution is selection, or adventageous. There’s also evolution due to “genetic drift”, which most often happens due to a sampling error in small populations. This can be explicitly counter to selection, as inferior genotypes may become more prevalent.
2) Mutation is not a form of evolution. It forms the genetic variation that is required for natural selection to take place. So, the longer- and shorter-tusked elephants have different DNA due to mutations in the past. Selection, in this case due to human activities, is making the shorter-tusked elephants more abundant in the population
January 23rd, 2008 at 10:07 am
This is interesting. Everyone here seems to think that an overall loss of genetic information equals an advancement (or evolution) in elephant DNA. If evolution means a gain in genetic information (for how could a pig-sized mammal with a stubby nose become an elephant without gaining entirely new genes), how does the loss of long-tusk DNA equal an evolutionary gain? If the long-tusks are completely eliminated from the gene pool, we will still have only elephants, and furthermore, we will have genetically less-complex ones. The engine of evolution is to gain new genetic material and these elephants are being pushed a step backward.
This looks to be nothing more than an unplanned breeding technique, similar to those employed by farmers or animal breeders. These techniques produce a certain sub-species, but always at the cost (loss) of genetic information, not a gain.
This article sounds like propaganda to me: “Look! Nature solved the problem of poachers with EVOLUTION! As progressives, we totally believe everything evolution scientists say! We can go back to sleep now!”
January 30th, 2008 at 6:58 pm
All evolution requires is changes in DNA (deletion, insertion, mutation, etc.) and there is no such thing as devolution so this can’t be a “step backward”.
In general, I prefer people trusting mainstream scientists over other sources. Scientists can be wrong but science works.
February 25th, 2008 at 10:32 am
February 29th, 2008 at 5:18 am
derick, you just dont get it. evolution doesnt necessarly mean better. evolution is defined as the change in a gene pool over time. THIS IS STILL EVOLUTION. you are using terms in their wrong context. get over it. THIS IS EVOLUTION. plain and simple. god some people really piss me off sometimes trying to sound like they know it all.
February 29th, 2008 at 5:20 am
PS.. just so you realise. degradation applies to a CHEMICAL COMPOUND. yes, elephants are totally classed as “chemical compounds”…jesus dude. know what you are talking about before you say something. u cant take terms applying to one thing and slap it into another. fool
April 1st, 2008 at 5:46 am
derick, that really is just very ignorant. you can’t even label it as a genetic deletion, because no one has shown what the difference in the genotype codes for larger or smaller tusks. “degraded DNA” is non-functional and won’t code for anything. and degradation of a compound is simply completely irrelevant to the point you are failing to prove. evolution is recognized as any shift the genome and the phenotype. the elephants are ADVANCING evolutionarily because the trait of having smaller tusks is more FIT.
take a biology class before you throw absurd claims around.