White Lions and Tigers - Yay or Nay

[patrick]

hey jeremy,

the word melanistic only refers to dark coated animals. the stuff in our skin, human skin, that causes us to tan is called "melanin". the degree of melanin in your skin effects the colour of it.

as stated above melanistic jaguars and leopards, are a mutation that has, since it often offers no real disadvantage, become a hallmark of the species. it is naturally dispersed through teh populations of these animals and melanistic animals therfore need not be inbred. for that reason we should have zero issues with zoos displaying and mixing melanistic leopards and jaguars into the general zoo population. the important thing is that this mutation established itself naturally, long long ago. unlike white tigers and lions the melanistic trait does not need us and our intentional inbreeding to ensure its survival.

 

[NZ Jeremy]

Thanks for the info Patrick,

I agree, so is focusing on the 'white gene' in the Lions and Tigers recessive breeding..?

 

[patrick]

so is focusing on the 'white gene' in the Lions and Tigers recessive breeding..?

if by that you mean is a recessive gene responsible for white tigers and lions the answer is yes, it is.

as is the case with melanistic leopards (though its apparently a dominant gene is responsible for black jaguars)

in any event its all mutation and trial by natural selection - the process that drives evolution. however, in the white tigers and lions, natural selection dictated it to be an unsuccessful mutation, whilst it endorsed melanism as something potential advantageous.

thus if we release white lions and tigers in the wild, we are polluting the wild population with genes proven by nature to be unsuccessful. with lion and tiger populations shrinking all over the world, why would we ever wish to put that added pressure on them?

not only are we poaching them, their prey and destroying their habitat, are we are now going to mess with their natural evolution as well? injecting unfavouring genes into their population?!!!

fortunately, despite all the talk, i'm yet to hear of any white cats released in the wild.

so thats why if you are at any zoo or individual that associates white lions/tigers with conservation is actually full of %@&* and feel free to tell them such.

 

[Sun Wukong]

Then the white lion Gandor (who was freakishly huge) and a lioness in a small enclosure...

Interesting-the white males I saw so far were not really impressive in comparison to most of the "normal" lion males I saw so far. Did You make a photo of him by chance? EDIT: nevermind, just used google; he looks to be pretty long-legged, isn't he?
I have never heard that hypermelanistic (that term would actually be more appropriate) animals have a shorter life-span; what I heard, read about and even witnessed myself once is the accumulation of health issues in white tigers-kidney & neurological deficits, anaesthesia problems, reduced intelligence, face deformities ("bulldog" face)-most likely a result of inbreeding depression. I'm personally rather happy that these poor creatures have not become common in most European zoos-let's hope it stays this way.

 

[NZ Jeremy]

When at this park I remembered thinking he was very large...

He didn't move in the five minutes or so I observed him... He was sitting on his haunches with his front legs straight and on top of a log, so that could explain my impression...

I was referring black jaguars/leopards... I remember reading a few years ago that when they occur outside of the rainforest areas of their range that it has a negative effect on their lifespan...

 

[patrick]

I was referring black jaguars/leopards... I remember reading a few years ago that when they occur outside of the rainforest areas of their range that it has a negative effect on their lifespan...

i don't imagine a black, heat absorbing coat is helpful in hot, dry savannah areas of the americas and africa. i have read the black individuals in savannah areas tend to be more nocturnal that usual as a method for counteracting such. nor would a black coat seem quite as camouflaged in a savannah as a yellow, brown and black spotted one. of course the situation may very well be reversed in the cooler, dark rainforest. certainly in parts of forested asia, black leopards dominate. apparently the same is true in parts of the jaguars range.

interestingly a pair of black jaguars can produce spotted offspring, whilst two black leopards will breed true to their coat colour (due to the gene responsible being dominant in jaguars and recessive in leopards). the interesting thing about this is, that it means whilst both species shared a relatively common ancestor, the black mutation has popped up independently and differently in each species, after they have split.

and yet the result is the same. for both cats, melanism, regardless of how its produced in the genes, has proven highly successful.

both leopards and jaguars are highly diversified cats. they inhabit (or once inhabited) a wide range of habitats from savannah to deserts and rainforest to temperate woodlands. few other big cats can adapt to such a wide range of habitats. could it have something to do with the fact that these animals carry this black gene diluted amongst the population and ready to pop up and prove itself whenever a favouring habitat arises?

 

[NZ Jeremy]

the interesting thing about this is, that it means whilst both species shared a relatively common ancestor, the black mutation has popped up independently and differently in each species, after they have split.

This has a special name: convergent evolution (check out the wiki page, quite interesting)...

could it have something to do with the fact that these animals carry this black gene diluted amongst the population and ready to pop up and prove itself whenever a favouring habitat arises?

That makes a lot of sense to me..!

 

[ptig]

White lions/tigers

I have to disagree with portions of Patrick's recent post. There seems to be a confusion about breeding tigers or lions in captive situations as being a conservation effort. Captive tigers, for instance will never be returned to the wild in any meaningful way, just is not going to happen. Zoos have hidden under the cover of endangered species programs for far too long.

There are exceptions with certain species but big cats are not among them.

The value of captive tigers or lions is to raise awareness and funds for in-situ conservation. White tigers and lions are probably even better draws and as such better at raising funds and getting attention to issues.

 

[Monty]

I did see a documentry where captive bred Siberian tigers were being released into the wild. The survival was poor, I think only 3 out of 25 survived long.

 

[Sun Wukong]

@ptig: Even if the white colour morphs are more attractive, I see no good in keeping and especially breeding animals with obvious health problems. This applies for both zoo as well as for domestic animals.

And in reference to the dwindling numbers of wild big cats: who knows; maybe some day, the specimen in zoos will be the only ones left. A terrible vision in terms of possible re-introduction, but unfortunately possible.

@patrick: Your question about correspondence of widespread habitat/colour morphs: don't forget e.g. the Jaguarundi & cougar with their different morphs.
There is another animal interesting in this context: the Common European adder. Its black morph, also called "Hell snake" in German, seems to occur mainly in the more Northern, colder areas of Europe-most likely, the black colour might help the snake to gain more heat from the sun and thus be longer active than other morphs when the days become shorter.
Which makes me wonder: has anyone ever heard of a black specimen of the Amur or any other of the more Northern leopard subspecies?

 

[ptig]

white tigers

@sun wukong- There are hundreds oif white tigers around the world. Certainly there are some with inbreeding issues. The vast majority are healthy animals that do represent an animal that existed in the wild for hundreds or thousands of years. They do have an important role in tiger conservation.

 

[Sun Wukong]

No, ptig-there are not just "some" with inbreeding issues; the correlation between the accumulation of definite health problems and the white morph is obvious; the very same is true in several cases of white domestic breeds, f.e. Dalmatian, white Bullterrier or white cats. It's truly not a "vast" majority of healthy animals, but rather the opposite. White tigers, btw., did not exist for "hundreds or thousands of years" in the wild; there have been very few reports of examples of the white morph in the wild, which just underlines that this is an occasional variant that does not prevail due to being not an advantage in competition (keeping the recessive heredity in mind). The extremely narrow founding base of the white tiger morph found nowadays in human husbandry and its deliberate inbreeding and subspecific interbreeding disqualify these animals, together with the health handicap, from having an important role in serious tiger conservation. The deliberate deception of the public by unscrupulous advertisement that this morph is an endangered species or subspecies is just another bone of contention.
MUTANT BIG CATS

 

[snowleopard]

Sun Wukong is correct, as there have been numerous incidents of white tigers being deformed or destroyed at birth due to a series of defects. Inbreeding has tarnished the lineage of several tiger families in captivity, and it is a genetic trait that is rarely apparent in wild cats. The fact that it would not at all be advantageous allows for the commonly held belief that such individuals would not last as long in the wild as their more "normal" counterparts. Any deception of the public in terms of "conservation" is nothing but snake-oil salesmanship.

 

[zoogiraffe]

Sun Wukong ,just to l;et you know their is a female Black Amur Leopard at Thrigby Hall Wildlife Gardens in the U.K so they do occur.

 

[Chlidonias]

This has a special name: convergent evolution (check out the wiki page, quite interesting)...

Melanism cannot be treated as an example of convergent evolution. It occurs in at least 18 species of cats, in some more commonly than others.

 

[ptig]

white tigers

I have seen many white tigers at many facilities and it is the minority that are compromised. They did exist in the wild as they have been depicted in Indian antiquities for over one thousand years. There are examples of adult white tigers in the wild as well.

The value to conservation of any tiger in captivity is to raise awareness and funding. White tigers can do this quite successfully. You might at least concede that point.

 

[patrick]

Melanism cannot be treated as an example of convergent evolution. It occurs in at least 18 species of cats, in some more commonly than others.

exactly why it would be a case of convergent evolution right? even if it is a rather poorer example of such. see, as i said earlier, the fact that melanism is caused in leopards and jaguars by different kinds of genes means it appeared independently in both species. if melanism in felines was not a case of convergent evolution ALL cats displaying melanism would have acquired it from a common ancestor and the gene responsible would be the same in all.

melanism, however is probably one of natures simplest mutations and its present in many species other than just cats. on the whole, it doesn't effect the chances of survival of many of the animals who develop it. at a guess thats why its so common. a very simplified case of convergent evolution in but an example of it nonetheless.


(of course some cat species may have acquired it via ancestory, but at least in the leopard/jaguar case - as far as my limited knowledge goes, it couldn't be the case.)

 

[Django]

exactly why it would be a case of convergent evolution right? even if it is a rather poorer example of such.

Sorry, I'd say so poor as to be useless, given that almost any species can produce a colour variation by genetic mutation.

Better examples are things like the grazing habits of deer and kangaroos, spots on quolls and cats, condors and vultures, that sort of thing, where completely unrelated species exhibit similar traits in response to similar environmental factors.

 

[patrick]

useless?

to put it back into context the words "convergent evolution" was originally mentioned by jeremy as we discussed the fact that in both leopards and jaguars, melanisim has become a common trait of the two,very similar species, due to different genes.

maybe not the most extreme example of convergent evolution, but certainly not useless given the context of the conversation.

 

[patrick]

response to ptig

I have to disagree with portions of Patrick's recent post. There seems to be a confusion about breeding tigers or lions in captive situations as being a conservation effort. Captive tigers, for instance will never be returned to the wild in any meaningful way, just is not going to happen.

but just because its so far failed to happen doesn't mean that those captive
populations of tigers are not potentially useful to the preservation of the species. just a little bit of new genetics from zoos stock (and it probably will be just a little bit with less than ten captive founders!) might be very useful to a ever dwindling population of just a few hundred sumatran tigers.

i agree its not necessarily much compared with the importance of preserving the species (and its genetic diversity) in the wild, but it is a potential lifeline for some species further down the track if things get really bad. a good example is the amur leopard now there is an example of a subspecies that is effectively "screwed". the last remaining population is down so low, they are probably functionally extinct in terms of their genetic diversity. they however be saved by the genetics that exist in captive amur leopard populations. and it is possible to inject captive pantherine bloodlines into genetically impoverished wild populations without returning animals to the wild...

unfortunately, however here is an example of and 11th hour situation when a captive breeding program proves itself - though i know of not a damn zoo with purebred amur leopards considering getting any of their bloodlines back into the wild population.

you see i hold strong faith in the value of captive breeding programs - unfortunately however i agree many zoos don't, instead more concerned with having an animal for display. phasing out hybrids, unnatural colour mutations and preserving genetic diversity (if any) within the captive collection are thus practices becoming more common which i fully praise.

knowing when and how to utilise these captive populations when needed is another issue..

ptig - ask yourself, is the problem zoos failing to value or manage CBP's as well as they should and failing to put them into effect when necessary?

or is it that captive breeding programs, as you say, are really are of no value other than education?


i would say the former..