Thursday, October 16, 2008

Are These Cubs Related? Melanistic Leopards aka "Black Panthers"




Until recently, I always thought the “black panther” was of its own species. I never realized it was actually a leopard in disguise. When I think of a leopard I think of a yellow colored animal with spots all over it, running through the dry desert. On the other hand, when I think of a black panther, I picture a sleek, black colored cat lurking in a rainforest. The funny thing is, this is the same animal. The leopards’ scientific name is Panthera pardus. Leopards are found in Sub-Saharan and North Africa, Middle East and Asia Minor, South and Southeast Asia, and the Amur Valley in the Russian Far East.
Their fur color varies, ranging from pale yellow to deep gold or tawny, patterned with black rosettes. Leopards have melanic variants, which are often referred to as the “black panther”. The “black panther” is not a separate species however. Melanistic coat coloration is a common polymorphism in 11 of 37 felid species. It reaches high population frequency in some cases but never achieves fixation (Molecular Genetics and the Evolution of Melanism in the cat Family, 2003).

This article talks about why there are so many black leopards in Malaysia. A researcher was studying tiger density in Malaysia’s Taman Negara National Park and set up cameras in the rain forest in which the animals could trigger trip wires and photograph themselves. In doing so, she found an unusually high number of black leopards but no pictures of spotted leopards. Black leopards have black fur due to a mutation in a single recessive gene that controls the coat color. Because the mutation is recessive, black and spotted leopards can be born in the same litter from two spotted adults (such as in the picture above). Researchers Eduardo Eizirk, Stephen O’Brian, and their colleagues at the National Cancer Institutes Lab of Genomic Diversity in Maryland, have mapped, cloned, and sequenced the genes responsible for black coats in cats. They proposed that since the melanistic form is so common in leopards and other cat species, it must have some survival benefit. Recent studies have shown that coat color genes also affect the immune system. The types of receptors for coat colors are also used by viruses to enter the cells, so in some way the color mutations could be adaptive. On the other hand some scientists propose the black leopard may be prevalent in Malaysia because they live in dimly lit rain forests and it could provide camouflage for them as opposed to living in the dry fields of Africa, where the sandy spotted fur color would be more advantageous.

Posted by Julie Riley (week 5)

Response:

Melanistic leopards are black, but still show the rosette pattern, which is why the black leopard cub in the picture shows a pattern underneath its coat. The pattern gives a silky, gray appearance. Leopards are found in many different places, as stated in the original post, and melanistic forms occur throughout its range, mostly in humid areas (Seidensticker & Lumpkin 1991; Nowell & Jackson 1996). Coat color varies across different habitats and Pocock (1932) describes four different patterns corresponding to rain forest, semidesert, savannah, and high mountain leopards. In Africa, melanistic individuals are not common because it is not a camouflage advantage. On the contrary, as many people assumed, more black variants are found in rainforest and mountainous areas, especially the Malayan Peninsula, as the posted article talks about.

Molecular genetic studies done in mice identified several genes involved in pigmentation phenotypes, including loci involved in melanism, such as agouti/ASIP (Agouti Signaling Protein) and extension/MC1R (Melanocortin-1 receptor). Melanism is the result of recessive variants of agouti, while dominant mutations in MC1R are the reason for melanism. In the domestic cat, black coat color is inherited as a recessive trait, which suggest agouti may be the cause. However, in jaguars, Panthera onca, melanism is the result of a dominant inheritance pattern, suggesting MC1R may have something to do with it. This study also found that melanistic individuals from five other felid species didn’t carry any of these mutations, which suggests there are at least four independent genetic origins for melanism in the cat family.
I noticed the black squirrels on campus recently as well. I find this topic to be very interesting because there are a number of species in which melanistic variants are common, and I would like to know how this feature evolved, and why.

References:

Phylogenetics, genome diversity and origin of modern leopard, Panthera pardus.
Olga Uphyrkina, Warren E. Johnson, Howard Quigley, Dale Miquelle, Laurie Marker, Mitchel Bush, and Stephen J. O’Brian.
Molecular Ecology, 2001.

Molecular Genetics and the Evolution of Melanism in the cat Family.
Eduardo Eizirik, Naoya Yuhki, Warren Johnson, Marilyn Menotti-Raymond, Steven Hannah, and Stephen J. O’Brian.
Current Biology, Vol.13, 2003.

Posted by Julie Riley

8 Comments:

At 8:38 PM, Blogger PWH said...

On the black cat in the picture you can see little patches of a lighter color. I always thought black panthers where pitch black, so do all of them have this kind of coloration? Also, it is interesting to think that maybe their coloration can aid in survival, but this will all depend on the environment they live in. Therefore, since black panthers can be born from two parents with light coloration wouldn't its coloration make it less fit to survive because it is likely that parents with light coloration live out in the dessert. Or in this case would the black panther just remove itself from the family and move to a forest where it is better camouflaged? Do these types of cats stick together as a family or spread apart? I think these are good questions to think about when studying whether or not their coloration is a means for survival.

Chantal Gomes

 
At 10:59 AM, Blogger PWH said...

Thats amazing for the longest time I assumed the spotted leopard and the black panther were separate species. I wonder if there might be other advantages/disadvantages of having the black coat color within the species.

-Joanne Philippeaux

 
At 11:49 AM, Anonymous Anonymous said...

I would never have thought that color genes could help with other systems. Its interesting because i was just watching a show where they were searching for black leopards in the US, and they were talking about how its odd for them to be here given the habitat, but maybe this gene is helping them remain healthy in certain areas.

Erica Damon

 
At 6:56 PM, Anonymous Allison Cornell said...

This comment has been removed by a blog administrator.

 
At 7:19 PM, Anonymous Anonymous said...

I used to intern at the Forest Park Zoo in Springfield, and we a few years back we aquired a leopard cub who was the "normal" color. However, he had one "normal" parent, and one black parent. The theory behind the different colored leopards is the same as behind the black squirrels on campus; same species, but different genes for coat color. Black leopards do have the same spots that normal leopards have, they're just harder to see since the cat is dark all over.

-Corinne Delisle (5)

 
At 7:29 PM, Anonymous Allison Cornell said...

I didn't know there were so many species of cats that had the melanistic colorations. I generally only think of leopards having the black variation. Do the parents of the leopards treat the cubs differently if they are of the darker coloration? I had no idea that coat color had any correlation with the immune system. Very interesting. Which coloration has more of an immunological advantage?

~Allison Cornell (5)

 
At 8:47 PM, Anonymous Anonymous said...

The picture is adorable!!! I love panthers and I'm glad that my suspicion of panthers and leapords being one and the same has finally been confirmed. I was wondering if a leapord born in a dryer area that was "black" in color would be more likely to move to a more forested area, if it was nearby, or stay where it's parent most likely taught it to hunt.

Ada Marie Flores

 
At 11:38 PM, Anonymous Anonymous said...

Wow, I would never expect these two species to be the same. Does these two species treat each other any differently since they are the same?

- David Huynh

 

Post a Comment

<< Home