Genetic analysis uncovers four species of giraffe, not just one

Science Daily ^ | 9/8/2016 | Fennessy

[JimSEA]

Up until now, scientists had only recognized a single species of giraffe made up of several subspecies. But, according to the most inclusive genetic analysis of giraffe relationships to date, giraffes actually aren't one species, but four. For comparison, the genetic differences among giraffe species are at least as great as those between polar and brown bears.

The unexpected findings reported in the Cell Press journal Current Biology on September 8 highlight the urgent need for further study of the four genetically isolated species and for greater conservation efforts for the world's tallest mammal, the researchers say.

"We were extremely surprised, because the morphological and coat pattern differences between giraffe are limited," says Axel Janke, a geneticist at the Senckenberg Biodiversity and Climate Research Centre and Goethe University in Germany. Giraffes are also assumed to have similar ecological requirements across their range, he added, "but no one really knows, because this megafauna has been largely overlooked by science."

Giraffes are in dramatic decline across their range in Africa. Their numbers have dropped substantially over the last three decades, from more than 150,000 individuals to fewer than 100,000. Despite that, the researchers say that there has been relatively little research done on giraffes in comparison to other large animals, such as elephants, rhinoceroses, gorillas, and lions.

[JoeFromSidney]

Giraffes are proof that God has a sense of humor.

[Dr.Deth]

Those giraffes you sold me... they won't mate.

[Harmless Teddy Bear]

Is a mule a separate species from donkey and horse?

Yes.

And horses and donkeys are not the same species.

They don't have the same number of chromosomes which leads to their having infertile offspring.

[BroJoeK]

JimSEA: "An article that makes a logical follow on to the Cambrian Explosion posts from yesterday."

Thanks, hugely appreciated!

[stremba]

Thanks I was not aware that the female lion/tiger hybrids are not sterile. Since the males are, like you said, that means that these hybrids cannot reproduce, so I believe that would mean that lions and tigers still qualify as seperate species.

[Religion and Politics]

hmm. I am going to go a different way on this one, but it is a follow on to the thought presented in the other thread about Wallace.

To what end does the human capability to identify and classify the species of Giraffes according to their DNA serve to preserve the survival of humans? Was the capability arrived at by innumerable gradual genetic successions handed down to offspring? Why would humans work towards preserving species that otherwise would go extinct due to current environmental pressures?

Note, I am not posing a question about the value of identifying and preserving. I am posing a question about how that ability arose through the process attributed to evolution for all life that we observe on Earth. So, this is the "problem" with natural selection that Wallace discussed, and which he reserved for humans alone. He thought that the difference between humans and the next lowest animal was too great to be explained by natural selection alone.

[Religion and Politics]

Forgot to include you on the prior post.

Thanks.

[JimSEA]

Humans have a largely unique ability to pass their discoveries, beliefs, analyses, on to their children. Eventually writing gave the benefits of the knowledge of many generations. “Standing on the shoulders of giants” if you will.

[BroJoeK]

lee martell: "But I’m wondering if the Giraffe and Camel are closely related?"

Giraffes & camels belong to the biological order called artiodactyl -- even-toed ungulates.
From Wikipedia:

"The roughly 220 artiodactyl species include pigs, peccaries, hippopotamuses, whales, camels, llamas, alpacas, mouse deer, deer, giraffes, antelopes, sheep, goats, and cattle..."

[lee martell]

Thank you. Giraffes have always struck me as being gentle and usually low key. I don’t know if I got that impression from Walt Disney or what, but I’ve never seen a Giraffe being combative with humans. I think I recall seeing two young male Giraffes charging each other, but not people. Camels? oh yes! They put the ‘Can’ in cantankerous!

[BroJoeK]

Boogieman: "...for example, if there are 2 groups of chimps who live on opposite sides of a river, and they cannot cross the river, it doesn’t matter if they could produce offspring, they would still be considered separate species."

Obviously some deep confusion on this whole subject...

No, not separate species.
There are only two species in the genus Pan -- Chimps & Bonobos.
Amongst Bonobos there are no sub-species, but Chimps have four sub-species, and here is where you get populations living on different sides of the big river belonging to different sub-species, even though they can and occasionally do interbreed.

Indeed, this whole idea of interbreeding is one, but only one, key factor in naming breeds, sub-species, species, orders, families, etc., etc.

The general rules go like this:

1. Breeds, varieties or races (in humans) of the same species eagerly interbreed and produce viable offspring.
   Examples include domestic dogs and, of course, humans.

2. Among sub-species of the same species we begin to see reluctance, but they still sometimes interbreed and produce viable offspring.
   The most recent example is the discovery of DNA data showing occasional interbreeding between modern humans and Neanderthals, now classified as a human sub-species.

3. Different species of the same genus do not normally interbreed in the wild, but can on rare occasion and also can be forced in captivity.
   Their offspring are normally viable.
   A good example here are Polar and Brown Bears which occasionally mate in the wild, producing fertile offspring dubbed "Grolar Bears".

4. Different genera of the same family do not interbreed in the wild and when forced produce infertile offspring.
   Indian & African Elephants fall into this category.
   Horses & donkeys do also, even though both are in the genus Equs.
   But donkeys belong to a separate sub-genus, Asinus, which recognizes their inability to produce fertile offspring with horses.

5. Different families of the same order cannot be forced to interbreed, at least so far as I've ever heard.

So, if you keep in mind that the degree of difficulty in interbreeding is a major factor in determining which creatures belong in the same breeds, sub-species, species, genera, families, etc., etc., you'll be right about it far more often than wrong.

[DouglasKC]

I don’t recall ever seeing a Giraffe utilized as a beast of burden, or even ridden by a grown man.

You're welcome.

[Boogieman]

The confusion is you are confusing my theoretical example for the real world situation. I’m not talking about 2 real species of chimps, just illustrating a point.

“even though they can and occasionally do interbreed...”

Yes, that’s why in the real world, they aren’t separate species. In my example, they didn’t interbreed, so they would have to be classified a separate species.

[lee martell]

SHOCK!! Although in this instance, both the Giraffe and the rider appear to be young. Still, it shows you that they can be mounted. Very elegant, graceful animals.

[BroJoeK]

Boobieman: "In my example, they didn’t interbreed, so they would have to be classified a separate species."

Got it. :-)

[SunkenCiv]

Note: this topic is from 9/08/2016. Thanks JimSEA. Besides describing eight or so species, there's reference on the wiki-wacky to the various, entertaining African folk tales about how the giraffe got that long neck.

• Giraffe From Wikipedia

[bert]

Yes

“Africa was very interesting. I took up being cruel to animals, but only as a hobby... You may be interested to know that I am singlehandedly responsible for the evolved shape of the animal you came to know in later centuries as a giraffe”