I completely agree, the old definition just will not do.

However, people must be careful blindly assuming DNA results will be the solution, as it stands.

DNA does not discretely package subjects into species for us.
it merely reveals similarities and differences, often reported in precentages, between the genetic information of subjects.

it is up to us to determine how to apply this and create the standards for species differentiation.

in other words, if we rely on DNA results, then what becomes the new definition, or standard, for speciation?
do we have a percentile value of difference established as the benchmark?
i.e. any two subjects with greater than 6.78% genetic dissimilarity are defined as separate species (or greater), with 6.78% or less are then classified as subspecies?
(this value is purely arbitrary for illustrative purposes).

as it stands, that magic number is not established, and all DNA results can give us is a “wow, those two things are awfully similar” moment.

the process of evolution is a constant differentiation of forms by the most subtle and slight of changes.
lifeforms with very high repopulation rates could easily alter themselves out of their named species within a single human’s scope of observation.

how genetically similar are the nile crocodiles of today compared to those during the reigns of the ancient pharaohs of egypt?
how genetically similar are we to those same humans?
of course we are still the same species, but there would undeniably have been appreciable genetic alteration in the intervening time.

nature does not have the concept of species as we do.

just like metres and kilograms, if we wish to measure life out into species, then we need to establish solid criteria that we have to invent.
DNA alone makes no statements.

mystery_man responds:
June 15th, 2009 at 7:33 am
“…I have to admit that I am a “splitter” (for those not familiar with this word, it means someone who favors breaking animals down into very specific taxonomical categorizations)”

me too. and i hope once we establish a quantifiable standard for measuring speciation using DNA, we will see some taxonomic reshuffling.

Great job! I look forward to the other parts.

BTW, I must admit I did not know fish can produce hybrid offspring. I always learn something new every day here. Thanks, Brent.

And I do agree with Kittenz that it’s not “stretching” to suggest that the Honshu may still exist in a remote corner of Japan. Hopefully, that is so.

Anyway, it is not only canids that defy the traditional definition of species. Some mammals such as bears can produce fertile offspring. For instance, polar bear/brown bear hybrids have produced fertile offspring, and Kodiak bear/ polar bear hybrids have been shown to be fertile as well. The full extent of fertility between members of Ursus has not been completely established, but all but a few species can interbreed with each other without a problem.

Many species of cat can produce fertile offspring too, especially small species of feline. For example, there have been fully fertile hybrids between domestic cats and European wildcats. Also domestic cat and steppe cat Felis caudata crosses have been shown to be fertile, as well as hybrids from domestic cat and jungle cat crosses, to name a few.

Many types of fish can produce viable hybrid offspring as well.

In fact, the whole definition of species as being strictly “two groups of animals that cannot produce fertile offspring,” is becoming pretty old fashioned and not very useful for modern taxonomy. With what we are learning about genetics and species plasticity, the old definition just doesn’t seem an adequate yardstick for taxonomical classification anymore. We are finding that the boundaries between species are a lot more malleable and plastic than was once thought and so there are other criteria that are considered beyond the simple ability for two animals from different species, or even different genera, to produce fertile offspring.

That being said, I have to admit that I am a “splitter” (for those not familiar with this word, it means someone who favors breaking animals down into very specific taxonomical categorizations), and think the Honshu wolf meets certain other criteria for being classified as its own species.

Anyway, I hope everyone will enjoy this series on Japanese wolves.

look forward to part 2!

There are those who argue that the physical differences present were enough to consider the Honshu wolf as its own species instead of merely a miniaturized grey wolf.

- I am one of those people. The whole concept of “species” as defined as “a group of animals capable of interbreeding to produce fertile offspring” has to be thrown out the window when it comes to canids, especially to wolflike canids such as dogs, wolves, coyotes & jackals. Wolves, coyotes & jackals can all interbreed with dogs and with each other to produce fertile puppies. There are credible reports of dogs being bred to dholes, and even foxes (I don’t know if the offspring from those intergeneric breedings were fertile. I doubt it).

The native dog breeds of Japan bear a strong resemblance to the Japanese wolves and are thought to descend (at least in part) from them.

Wild canids can be extremely cryptic. In the area where I live, there are red and gray foxes, and coyotes. Lots of coyotes. But you rarely see them, even as roadkill. The vegetation is very lush, and the mountainous, rocky terrain with its steep slopes and gullies provides a lot of cover.

If coyotes can exist here without many people even being aware of them (until they start losing cats and livestock), I don’t see it as a stretch to believe that at least a remnant population of Honshu wolves could survive to this day.