In retrospect, I really should have done the anaconda today; Lady GaGa's new video for "Alejandro," a song about a Latino harem, would have fit perfectly. It's almost close enough for me to call synchronicity, but not quite. Tch.
Instead, today's post will be devoted to one of Vegas's most popular residents: The white tiger. Although they've been around for longer than anyone could know, many of us know them from Siegfried & Roy's Vegas performances. Contrary to what playbills may tell you, none of the white tigers seen today are Siberian; they all have some Bengal lineage, which is just one of the many issues that tiger fans and experts like to pick on. There are also a few different kinds of white tiger, but the morph we will be focusing on is the common "white with black stripes" popularized by S&R.
Your hand has a flavor. *OMNOMNOM.*
This common color morph in Bengal tigers is a recessive gene dubbed 'chinchilla albinism.' Despite this, they are NOT considered 'albino' tigers in the strictest sense; a report from 1922 told of an albino mother tiger and her babies, all of which were stripeless with pink eyes.
This version of white-ness was first found in Bengal tigers, and has been in captive collections since the 1900's. This version of white coloration is linked to larger-than-average size, which may have helped it survive in wild populations. The trait is currently extinct in the wild, and even in its heyday would have occurred in only 1 out of every 10,000 Bengal tiger cubs.
It is also genetically linked to crossed eyes. All captive white tigers, due to outbreeding with Siberians and severe inbreeding, cross their eyes when stressed. The trait is getting rarer and rarer, and will probably be bred out. Strangely, this only seems to happen in Bengal-Siberian crosses; it is (was?) rarely observed in pure Bengal whites.
Bulging eyes...squished face...With a little imagination and long fur, and you could market this as a shishi!
Regardless of how much money well-meaning zoos make off of white tigers, there are a good amount of people against keeping them. They have at least one point right: Though exotic, white tigers are NOT an accurate sample of wild tiger populations. These are not the tigers we should be looking at. An exception can be made for Vegas; zoos should really stop showcasing freaks.
Holy cats. I hate to sound racist, but...wait...are those black people? That video is from the African country of Tanzania, and those people look light-skinned, but they certainly aren't Caucasian. There are other traits that make them look African. Again, no offense meant.
The people in that video up there are albinos. That is not a racist term. That is the exact same sort of albinism that you see in Burmese pythons, that white gorilla, lab mice, and those white frogs at Wal-Mart. It just so happens to occur in people as well. Even so, not all white people, or animals, can be properly called albinos. Why?
Albinism (derived from Latin albus, -a, -um, "white") makes any given organism a lot lighter than usual. It is commonly thought of as the trait that turns animals white, and, as such, tends to be incorrectly oversimplified into "any white animal." It is found across many, many species, from fish to humans.
Albinism is a simple recessive trait - that is, something can be 'heterozygous for albinism.' That means that the parents of an albino progeny will look completely normal. There is a 25% chance of getting an albino baby (of pretty much any animal) if both parents are heterozygous.
What I said up there can be roughly translated into this little box.
Although 'albinism' is the common name for this mutation, 'amelanism' would be more accurate. The mutation stops the production of melanin (Gr. melanos, black), a common natural pigment. As the name implies, it determines the amount of dark coloration on an animal. Since albinism essentially turns that one pigment off (making the organism white), why not get more to the point? As you will see, not all albinos are plain white...but they all lack black pigment.
For mammals, melanin is the only pigment that they have to work with, so they end up being uniformly white. This is not so for birds, reptiles, amphibians, or fish - an albino Burmese python, for example, also has some yellow pigments to play with after albinism. The same also went for that crazy albino retic from my reticulated python entry - it had orange, peach and purple, of all things! A lot of people do not realize that albinism is just one giant PhotoShop tool that Mother Nature likes to play around with every so often.
Tweaking pigmentation is an awful lot like editing a picture in PhotoShop. For mammals, you can only work in a sort of sepia grayscale, but everything else has at least RGB to tinker with. This is why a lot of mammals share similar patterns and colors. When was the last time you saw a bright purple mammal?
Albino specimens also have vision problems. As with the light skin typical of albinos, the eyes also lack (or have very low) pigment. This makes them appear anywhere from light blue to the infamous pink with red pupils. Having pink eyes is not necessarily a criterion, but it is still a good rule of thumb when trying to pick out albinism from other types of whiteness.
That said, it's time for that pop quiz I promised. Which of the animals below are albinos?
The first two pictures - the white peacock and white tiger cubs - are not albinos. They are different variations of leucistic (from Greek leukos, white). Leucistics have no hard and fast rules or maladies like albinos. Even the heritability of the various leucistic types can vary. There are about a million types of leucism. Unlike normal albinism, leucism gels perfectly well with black.
So, yes, that infamous albino peacock is leucistic. It is hard to see the dark eyes on the peacock, but that it is not albinism is apparent when a white peacock meets and mates a regular blue peacock:
Remember what I said about albinism being a simple recessive trait? Breeding a truly albino peacock to a wild-type peacock should result in all normals that, when bred together, will yield 25% albino offspring. That's not what we're seeing here. Instead, we got a pied peacock due to that particular type of leucism's incomplete dominance. Eye colors aside, albinism doesn't roll that way.
White tigers are not albino, either. I have heard rumors of albino tigers, but the bold black and white specimens seen in Vegas are not albino. If they were truly albino, they would be completely white - the black stripes should be a warning flag. They have a type of leucism with a similar heritability pattern to albinism (i.e. it's simple-recessive). The gene is linked to a trait for severely crossed eyes; all white tigers are at least slightly cross-eyed. There are, supposedly, albino tigers - pure white tigers with no stripes at all - but the evidence for that is sketchy at best.
The squirrel is a real albino. I was not trying anything sneaky with that one.
These last two were trick questions. The blizzard corn snake (Elaphe guttata guttata/Pantherophis guttatus guttatus, depending on your gender today) is part albino, but true albino/amelanistic corn snakes look like something from Woodstock:
To get a truly 'albino' look, an albino corn snake has to be bred with an anerythristic (i.e. "lacking red") individual. (Since there are two types of anerythrism in corns, I may as well add that, should you desire a blizzard corn, the cross is Anery B/Charcoal x amelanistic/albino. Utilizing Anery A instead yields a snow corn, which usually looks far less pure than the blizzard above. Both are often mistakenly called albinos.) The resulting offspring will all be normal-looking hets for both traits. Breed them again for a 1/16 chance of a whiter snake. The Siamese cat is also a type of albino. In this case, the mutation is incomplete and temperature-sensitive. Like many albino animals, Siamese cats are susceptible to eye issues - mainly, crossed eyes - and tend to prefer daytime hours because they have poor night vision.
There seems to be a lot of misinformation going around. Keep your eyes peeled for mistakes, and somebody please correct me if I made any!
Your resident lover of weird creatures, foods, etc. Likes going outside and looking for faeries in whatever form they choose to take. Is fascinated by parasites, worms, snakes, and anything with wings.
