Month: October 2023

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A couple days ago, my friend texted me while they were looking at a black panther exhibit at the art museum and asked me what kind of cat black panthers actually are. I had to break it to them–and now to you–that there really isn’t any such thing as a black panther. The name “black panther” is applied to individuals of several species of wild cat which are all black due to a rare genetic condition called melanism. Most black panthers are actually leopards or jaguars, both of which are normally yellow with black spots [9].

What is melanism?

Melanism is a rare genetic mutation that causes animals to have black skin and fur/feathers/whatever when members of their species typically do not [1, 3, 4, 7, 9]. The mutation causes the affected animals to produce an excess of the dark color pigment melanin [1, 2, 7]. Lots of animals can be melanistic, including pigs, cows, mice, butterflies, snakes, lizards, and snails [2, 4, 7]. Melanism is more common in felids than most taxa, however [1-3, 7]. 15 of the 40 species in the genus Felidae are known to exhibit melanism [4].

Melanistic cats have black fur all over their bodies but may still have some of the patterning or their “normal,” or wild-type, brethren. For example, black leopards still have rosettes which are even darker black [7, 9], and some melanistic Asian golden cats have a white mark on the underside of their tails [4].

Melanism mutations have cropped up at least eight separate times in the cat family tree [3]. These different mutations don’t all work exactly the same way. Mutations in the ASIP gene are recessive, meaning that a cat has to inherit the mutation from both parents to be black [2, 7]. The ASIP protein normally inhibits eumelanin (dark pigment) production, and these mutations make the ASIP protein non-functional [2, 7]. Leopards and Asian golden cats inherit melanism as a recessive ASIP mutation [2, 3, 6-9].

Mutations in the MC1R gene are dominant, so a cat can inherit either one or two copies of the mutation to be melanistic [2, 7]. MC1R promotes the production of eumelanin, and the mutations increase its activity [2, 7]. Jaguars and jaguarundis inherit melanism as a dominant MC1R mutation [2, 9].

How many black panthers are there?

In general, the rate of melanism in the felid species that have it is thought to be around 10% [3, 9]. However, the actual percentage varies widely depending upon the species and specific population [1, 3, 4, 8]. Leopards range throughout Africa, up through Asia, and as far north as Siberia. In Africa, they are almost never seen in their black panther form, but in Malaysia, the exact opposite is true–almost all leopards are black [3, 4, 7-9]. Southeast Asia in general has about half melanistic, half wild-type leopards [3]. Servals are more likely to exhibit melanism in the East African highlands and the Tsavo ecosystem of southeast Kenya [1]. While most species have fewer melanistic cats than wild-type, 80% of jaguarundis are melanistic [2, 4].

It’s difficult to get an accurate count of how many wild cats there are in the world to begin with, due to their stealth and dwindling habitats. Counting black cats has its own particular challenges. Sometimes reports of a “black panther” are ambiguous or a case of mistaken identity [5]. There is still debate about whether or not melanistic cougars actually exist for that reason [5]. Because melanistic wild cats are rare in most environments, people are more likely to take notice of them and tell somebody if they see one, possibly inflating their numbers [1].

Why are only some big cats melanistic?

The evolution of melanism in felids is still up for discussion among biologists. The most prominent theory is that melanism is so common among cat species because it helps camouflage them in dark, forested places [3, 8]. As ambush predators–and sometimes prey for bigger animals–most cats specialize in stealth, so camouflage is important. This would explain why melanism is more common in cats in jungle habitats and very rare in open grasslands where a black cat would really stand out [3, 8].

Researchers have found some other possible benefits to being a black panther, too. Dark coloration may aid in temperature control in high-altitude or cool, moist forest environments [1, 9]. Research in dark-colored birds has shown that they are resistant to feather-degrading bacteria [3], so there is a possibility that melanistic felids have some additional immunity to disease [3, 8].

There may be some downsides to that glossy black coat, however, even in favorable habitats. Black leopard pairs have smaller litter sizes [6], although the melanism mutation itself appears to have no ill effects [7]. Graipel et al. found evidence that melanistic cats in some species may have a disadvantage in communicating with their peers because the lack the white spots behind their ears or on their tails characteristic of their species [4]. Wild cats use these spots to send signals to each other at short distances, silently, without alerting prey or predators [4]. This is more important for some species than others, depending upon their habitat and whether they are more active when it’s light or dark [4]. Some felids don’t have these spots at all [4]. So it’s more advantageous to dress in black for some cats than for others.

Miniature black panthers

One of the felid species that exhibits melanism is the domestic cat, Felis catus [7]. That’s right, you might have a black panther of your very own! Not all black housecats are melanistic, however, because coat color genetics are complicated. Melanistic cats will be solid black, absolutely no white hairs, and their skin will be black as well. Also, fun fact: melanistic kittens often have “ghost” tabby stripes that typically fade with time, like the black leopard’s shadowy spots [7].

Sources

1. Adkins, B. (2019, May 12). Melanism in servals. Sheldrick Wildlife Trust. https://www.sheldrickwildlifetrust.org/news/wilderness/melanism-in-servals
2. Eizirik, E., Yuhki, N., Johnson, W. E., Menotti-Raymond, M., et al. (2003). Molecular genetics and evolution of melanism in the cat family. Current Biology, 13(5), 448-453. https://doi.org/10.1016/S0960-9822(03)00128-3
3. da Silva, L. G., Kawanishi, K., Henschel, P., Kittle, A., et al. (2017). Mapping black panthers: Macroecological modeling of melanism in leopards (Panthera pardus). PLoS One, 12(4), e0170378. doi:10.1371/journal.pone.0170378
4. Graipel, M. E., Bogoni, J. A., Giehl, E. L. H., Cerezer, F. O., et al. (2019). Melanism evolution in the cat family is influenced by intraspecific communication under low visibility. PLoS One, 14(12), e0226136. https://doi.org/10.1371/journal.pone.0226136
5. Hartwell, S. (n.d.). Mutant pumas. Messybeast. http://messybeast.com/genetics/mutant-pumas.html
6. Robinson, R. (1970). Inheritance of the black form of the leopard Panthera pardus. Genetica, 41, 190-197. https://link.springer.com/article/10.1007/BF00958904 [Abstract]
7. Schneider, A., David, V. A., Johnson, W. E., O’Brien, S. J., et al. (2012). How the leopard hides its spots: ASIP mutations and melanism in wild cats. PLoS One, 7(12), e50386. doi:10.1371/journal.pone.0050386
8. Sunquist, F. (2006, December 1). Malaysian mystery. The National Wildlife Federation. https://www.nwf.org/en/Magazines/National-Wildlife/2007/Malasian-Mystery
9. Zaccaria, J. (2019, October 28). Wild cats 101: Black cats and more on melanism. Panthera. https://panthera.org/blog-post/wild-cats-101-black-cats-and-more-melanism

Published October 8th, 2023