Showing posts with label melanism. Show all posts
Showing posts with label melanism. Show all posts

Thursday, 28 April 2022

Melanism in cats - full discussion



The cat above is a "grizzled" Chausie in cat fancy language or a cat with melanism in more scientific language. She is a silver tipped black Chausie. The cat's name is "Shekinah" and she was raised on Tammy Isaac's Willowind Cattery in South Texas. The photo is copyright protected. The photographer is Helmi Flick.



This post is about melanism in cats. The same principles apply for any form of melanism. Melanism refers to the black pigmentation of melanin.  This pigmentation colors hair, iris of the eye and skin. The pigmentation in the hair, however, is more a very dark, inky, rich bluish/brownish grey as the black coat pattern is still visible as a ghost pattern. Cats that carry the gene mutation that causes melanism are called "melanistic cats". Melanism is caused by a dominant autosomal allele2. The same source says that it is caused by an "autosomal recessive gene"6. This is conflicting information and shows that science is unsure of the genetic mechanisms involved. The conflict may be due to the fact that a different gene is involved in different cat species.

The opposite effect is albinism, when hair, iris and skin lacks pigmentation altogether.

Melanism may be linked to an added resistance to disease. The following wild cats can be melanistic:

Scottish Wild cat
Indian (Temmincks) Golden Cat
African Golden Cat
Jungle cat (dominant gene melanism, silver tipped)
Jaguar (dominant gene melanism)
Leopard ("black panther")
Cheetah
Caracal
Serval
Lynx
Bobcat
Jaguarundi
Geoffroy's cat
Clouded leopard
Ocelot
Pampas cat (Cincinnati zoo)
Oncilla
Kodkod

Source: messybeast.com

Wild cats

Another phrase that is frequently used specifically for large wildcats is "black panther". Black panthers are melanistic cats. The specific wild cats that this phrase relates to is the jaguar and the leopard (see also: black leopard pictures). These are very similar looking wildcats but they live on different continents. Amongst the wild cats, melanism is most common in jaguars. At one time (incorrectly) black jaguars were considered a separate wild cat species. As mentioned, the pattern is ghosted (see image below). It can rarely refer to the cougar (mountain lion or puma) too. Melanistic pumas are localised or very rare1. A visitor to PoC claims to have seen a 40 lb black cat in Arizona. And please see: I encountered a seven foot long oily black mountain lion...

Melanistic jaguar showing ghost pattern - photo: by ahisgett

However, there are many other wild cats that are melanistic. Melanism seems to be common in some species of wild cat and less common in others. In addition to the jaguar and leopard mentioned above, the serval, kodkod, jungle cat, Geoffroy's cat and oncilla can be melanistic while it is a rare condition or localised in the Bobcat, clouded leopard (in Borneo only) and cheetah. Apparently melanistic Geoffroy's cats are common. Partially black and melanistic African golden cats have been observed3. As to the Bobcat there were reports of 10 black bobcats in southern Florida4. As to the cheetah there is a record of one being sighted in Zambia and one in Kenya5. Melanistic servals are found in the Abedare Mountains of Kenya as are also black leopards. Black leopards are also found in the foothills of the Ruwenzoris, the Ethiopian highlands, Congo and South Africa6.

Melanistic jungle cat (felis chaus) - Photo by Joachim S. Müller

Domestic Cats

There are some good examples of melanism in domestic cats on PoC. The best is probably the F4 Savannah cat that I photographed at A1 Savannahs called "Midnight".

F4 Savannah cat "Midnight" with melanism - Photo Michael 

Another is the F1 Safari cat (a wildcat hybrid). And heading this post is a black Chausie another wildcat hybrid domestic cat.

Genetics

Information about the genetics behind melanism in cats is very sketchy. I can say this with some confidence because Robinson's Genetics, the premier book on cat genetics, barely refers to it.

Sarah Hartwell on messybeast.com writes:
"Melanism is due to changes in the "agouti" gene which controls blackness (due to bands of colour along the hair shaft). Cats with normal agouti genes have ticked or banded hairs. Cats with 2 copies of the mutated agouti gene have solid colour hairs. In wild species this causes melanism (in domestic cats other genes affect the colour e.g. black, grey, brown). In most cat species, the gene for melanism is recessive to that for normal colour. In jaguars, melanism is a dominant gene."
Clearly the dominant (or recessive) gene that produces melanism causes the pigment, melanin, to be added to hair, skin and iris in a continuous manner at the time that the hair, skin and eyes are being formed. By way of contrast, the agouti gene causes pigment to be added to hair in bands producing the tabby appearance.

Biological melanin is called "eumelanin".

Notes:

1. Wild Cats of the World page 8

2. Foreman GE 1988 Behavioral and genetic analysis of Geoffroy's cat in captivity as referred to in Wildcats of the World page 206.

3. Wild Cats of the World page 247

4. Wild Cats of the World page 186

5. Wild Cats of the World page 21

6.  Wild Cats of the World page 320 (leopard description)

Michael Avatar

Melanism to Home Page

Monday, 7 June 2021

Pseudo-melanistic black tiger photographed in Odisha, India

ODISHA, INDIA, NEWS AND COMMENT: A lucky amateur photographer, Soumen Bajpayee, captured a black tiger, more particularly a tiger with thick dark stripes almost covering the tawny/orange background because of a genetic mutation described as pseudo-melanism. These tigers are said to be incredibly rare (as reported by the Daily Mail) which is why the photographer was incredibly lucky. I hope that he was able to sell his photographs for a decent amount of money. They also report that melanistic black tigers are only found in Odisha state and that the numbers have declined dramatically, especially recently according to a 2018 tiger count.

Pseudo-melanistic black tiger in Odisha state India
Pseudo-melanistic black tiger in Odisha state India. Photo credit per embossing lower left.

Most black tigers can be seen in the Similipal Tiger Reserve in Odisha. They first reported melanistic tigers in this reserve in 2007. A wildlife expert and scientist at the Wildlife Institute of India said that he believed that there were only 7-8 of these tigers left. They are said to be smaller than the standard-coloured tigers.

There is constant pressure on tiger numbers in India because of the continually growing human population, which squeezes out wildlife. I'm referring particularly to human activity which increases as the human population increases. It makes sense. Human activity is anathema to tigers in the wild.

Sarah Hartwell, an expert on cat genetics and unusual cats both wild and domestic, tells us that pseudo-melanistic tigers might be becoming more common due to inbreeding which in turn is caused by habitat reduction which in turn is caused by, as mentioned, increased human activity.

In the fact that pseudo-melanistic black tigers are smaller than the normal tigers also indicate inbreeding. Inbreeding promotes anomalous coat patterns and/or colours. This is because recessive genes are able to manifest themselves in phenotypes. Also, totally black melanistic tigers have been reported. Sometimes people misidentify a melanistic leopard which is totally black, or very dark charcoal coloured, as a tiger which may account for the assessment that melanistic tigers are smaller.

Sarah reports on some old accounts of black tigers. For example, in an ancient Chinese Encyclopaedia written circa 300 BC called Erya, there is a mention of a black tiger in a chapter headed "Explaining the beasts". It starts "The shu is a black tiger."

The book reports of a small black tiger with fur that was dark and luxuriant but "bore spots/stripes". The Tower of London menagerie which was founded in the 13th century by Henry III at one time had a black tiger from the East Indies it is said, but it is more likely that it was a black leopard.

The Daily Mail report is dated Nov. 2020.

Friday, 9 April 2021

What wild cats are black?

No wild cat species (as a species) is black. Sometimes individual wild cats of some species are black or dark charcoal because of a genetic mutation resulting in melanism. The classic melanistic wild cat is the black jaguar called the black panther. The puma can be black too and so can the bobcat, the serval, the leopard and Geoffroy's cat. These names come out of my head. I have probably forgotten some.

Black leopard (melanistic)
Black leopard (melanistic). Pic: Pixabay.

But the point is that the answer is NONE. It is just that some individuals do end up black against the usual colour of the species concerned because of this genetic mutation.

SEE SOME BLACK PANTHER PICTURES.

Melanism affects many animals of many species, not just some wild cats. For instance melanistic leopards are quite common. They are sometimes bred in zoos. Black leopards are caused by a recessive gene. They are less fertile than normal leopards according to Sarah Hartwell, a cat genetics expert.

Black leopards in captivity may be more highly strung than normal leopards because they are bred to entertain the public and in doing that they become inbred. This affects their mental health. 

As leopards are nocturnal being black does not impede hunting but probably has the opposite effect. Melanistic leopards are also called black panthers.

Sunday, 1 April 2012

Bright Eyed Melanistic Savannah Cat

Melanistic Savannah Cat by broadsurf
Melanistic Savannah Cat, a photo by broadsurf on Flickr.
This is a high hitting Flickr photograph of a melanistic Savannah cat that I created a couple of years ago now. I think she was female. She is a breeding cat and her mate was a conventional coated cat (spotted tabby as I recall).

She was living in an inside/outside enclosure. She would not have had much interaction with people and it showed. She wanted interaction with people because when I entered the enclosure quietly and sat down and did nothing to allow her time to adjust she looked quite startled.

She soon got accustomed to my presence. I had put my glasses high up on the cage and she immediately climbed up to check them out.

She then gradually approached and then began to lick me. She licked me so much I became wet with her saliva. She was very cute.

Her appearance had a wild quality. I felt that she was semi-wild. Her eyes are startlingly beautiful set against the rich melanistic coat. When the sunlight shone through her coat you could see the rusty coloured melanin pigmentation. Black is brown in the cat world.

What is surprising is that this photograph has received by far the highest number of views by visitors who come to my Flickr pages (channel). I am not sure why.

It is licensed by me for reuse "as is" meaning anyone can republish it provided they don't adjust it. You also have to provide a credit and a link back to the Flickr page.

I hope you like the photo. She was a great lady cat. I remember my time with her with great clarity. She must have made an impression on me. I think she was fourth generation from the wild (F4).

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