The forearm flag of felids as a retrievable ancestral feature depending on the local predatory regime

@paradoxornithidae @beartracker

In a previous Post (https://www.inaturalist.org/journal/milewski/54854-forearm-flags-and-caudal-flags-in-lynx-like-felids#), I showed that the bobcat (Lynx rufus) and the serval (Leptailurus serval) possess forearm flags, which ostensibly function as warning colouration nested within the overall camouflage colouration.

A trace of the forearm flag is visible in many other genera and species of felids.

It thus seems to be an ancestral feature, which can remain latent. When a population finds itself, through the contingencies of biogeography, in a predatory regime intense enough for the warning insignia to be genetically 'switched on' again, a resumption of the dark/pale contrast relative to the overall colouration needs little more than increased pigmentation/depigmentation.

The genus Felis is like the genus Lynx in showing this latency. Felis contains various populations, ranging from subspecies to species, in which the forearm flag has been reinstated in at least a proportion of individuals.

A prime example is one subspecies of the African wild cat (Felis lybica), the species from which the domestic cat (Felis catus, see https://www.warrenphotographic.co.uk/02253-brown-tabby-cat-walking and https://www.alamy.com/stock-photo-tabby-domestic-cat-walking-on-garden-fence-22304491.html) has been derived.

The inner foreleg is barred in several domestic breeds and in all wild subspecies, but is usually not noticeable relative to the overall colouration.

It is only in Felis lybica griselda, the wild cat of the Kalahari (Botswana and Namibia), that the forearm flag is expressed in virtually all individuals. This is possibly because the predatory regime relative to the available resources is particularly intense there (e.g. see https://www.outdoorphoto.co.za/blog/the-sighting-of-a-lifetime-leopard-catches-an-african-wild-cat/).

Here is the forearm flag in action: https://www.alamy.com/canis-mesomelas-black-backed-jackal-africa-image360657726.html.

It so happens that Felis lybica griselda is the best-illustrated of all the subspecies of this species. The following show the forearm flag clearly: https://www.lifewithcats.tv/wp-content/uploads/2016/02/africanwc.jpg and https://twitter.com/serbiaireland/status/1209976460448063488 and https://www.sciencephoto.com/media/967569/view/african-wild-cat and https://africageographic.com/stories/the-10-cat-species-of-africa/african-wild-cat-felis-lybica-willie-van-schalkwyk/ and https://www.flickr.com/photos/willievs/25245774617 and https://www.agefotostock.com/age/en/details-photo/african-wild-cat-felis-lybica-adult-walking-kalahari-gemsbok-n-p-south-africa/FHR-10188-00023-125/1 and https://www.mindenpictures.com/search/preview/african-wild-cat-felis-lybica-etosha-national-park-namibia/0_00541399.html and https://www.alamy.com/african-wildcat-felis-sylvestris-lybica-walking-in-the-kalahari-desert-image62686799.html and https://www.bing.com/images/search?view=detailV2&ccid=OuLBMfvt&id=8986BF0E3DEF60A8A2D11CECB528A6154AD35DBB&thid=OIP.OuLBMfvtoc1Bqbc3Vw0czAHaE8&mediaurl=https%3a%2f%2flive.staticflickr.com%2f4744%2f25245774617_7acedc6329_b.jpg&exph=683&expw=1024&q=african+wild+cat&simid=608023045455706090&FORM=IRPRST&ck=D51B82E27167A97280AF170A4932378F&selectedIndex=47&ajaxhist=0&ajaxserp=0 and https://www.alamy.com/african-wildcat-felis-lybica-also-called-near-eastern-wild-cat-wild-animal-in-nature-habitat-grass-meadow-nxai-pan-national-park-botswana-afric-image419070382.html and https://www.istockphoto.com/photo/african-wildcat-falbkatze-felis-lybica-african-wild-cat-gm467256551-33900756 and http://www.felidaefund.org/?q=species-african-asian-wildcat.

Turning now to other species of Felis, the same theme of latency and ambivalence is apparent.

In the European wild cat (Felis silvestris) only a few individuals qualify for a forearm flag: https://www.alamy.com/european-wild-cat-felis-silvestris-juvenile-walking-over-a-log-switzerland-image256527005.html.

The jungle cat (Felis chaus) seems to be at an evolutionary threshold between a conspicuous pattern and an inconspicuous one, or vice versa; and it also shows wide individual and possibly regional variation.

Although the species fails to qualify for a forearm flag, it illustrates the latency in the pattern. The range in expression is between https://www.treknature.com/gallery/photo17831.htm and https://www.shutterstock.com/nb/image-photo/jungle-cat-felis-chaus-wallking-across-1423398455.

In Felis margarita, an unknown percentage of individuals qualify for a forearm flag: http://www.catsforafrica.co.za/sand-cat-felis-margarita/sand-cat-walking-across-sand1/ and https://www.alamy.com/stock-photo-sand-cat-felis-margarita-walking-qatar-15612155.html.

Let us now turn to other genera of felids, with an eye to the same incipient/residual pattern on the inner foreleg.

In Puma concolor, the incipient/residual pattern is restricted to juveniles; there is no forearm flag despite the development of warning colouration on the face: https://www.northernjaguarproject.org/photo-gallery/other-mammals/mountain-lions/ and https://www.alamy.com/stock-photo-puma-cub-puma-concolor-1-year-old-standing-against-white-background-25916651.html and https://www.alamy.com/mountain-lion-cub-walking-on-frozen-pond-image224273389.html.

Some individuals of Lynx canadensis, L. lynx and L. pardinus show the incipient/residual pattern in adults: https://www.inaturalist.org/observations/82614162 and https://www.inaturalist.org/observations/79738031 and https://www.inaturalist.org/observations/63490564 and https://www.inaturalist.org/observations/55960158 and https://www.inaturalist.org/observations/55755981 and https://www.inaturalist.org/observations/34960043 and https://www.bigstockphoto.com/image-391224419/stock-photo-the-eurasian-lynx-%28lynx-lynx%29-walking-through-a-meadow-lynx-in-its-natural-habitat and https://www.dreamstime.com/eurasian-lynx-walking-green-grass-front-forest-young-male-background-morning-sun-image164479313 and https://www.alamy.com/adult-iberian-lynx-lynx-pardinus-in-andujar-in-spain-walking-past-the-photographer-image365331404.html and https://www.flickr.com/photos/naturetrek/19523465335. However, I have yet to see any individual of these three species in which the forearm flag is expressed on a par with 80% of individuals in Lynx rufus.

In the caracal (Caracal caracal), the incipient/residual pattern is visible in only a few individuals: https://owlcation.com/stem/Caracal-Adaptations-and-Facts and https://www.flickr.com/photos/willievs/39239134875/in/photostream/.

The closely related African golden cat (Caracal aurata) is particularly variable in colouration but the pattern is never bolder than in https://www.treehugger.com/african-golden-cat-kittens-photographed-first-time-4853278.

Finally for now, the following are worth examining:
Prionailurus planiceps https://wildcatconservation.org/wild-cats/asia/flat-headed-cat/
Prionailurus bengalensis https://www.researchgate.net/figure/A-leopard-cat-along-a-secondary-road-526N-11722E-Photo-A-Wilting-A-Mohamed_fig2_291496064
and Leopardus geoffroyi http://faunayfloradelargentinanativa.blogspot.com/2011/03/gato-montes-leopardus-geoffroyi.html and https://www.ecoregistros.org/ficha/Leopardus-geoffroyi&idusuario=713.

Also see
https://www.inaturalist.org/journal/milewski/55149-is-there-any-trace-of-a-forearm-flag-in-the-largest-felids#
https://www.inaturalist.org/journal/milewski/54854-forearm-flags-and-caudal-flags-in-lynx-like-felids#
https://www.inaturalist.org/journal/milewski/69407-nice-illustration-of-residual-incipient-warning-colouration-on-inner-foreleg-of-puma-concolor#.

Posted on 09 August, 2021 06:02 by milewski milewski

Comments

each post reads like an article in the Nature journal.

Posted by bobasil over 2 years ago

Thanks so much for all your very interesting journal articles. they are highly appreciated though it will take a long time to digest them all.

Posted by botswanabugs over 2 years ago

@botswanabugs I'm so glad that you enjoy this kind of discussion. And thanks to you too for posting your well-taken photos...

Posted by milewski over 2 years ago

Here are more photos of Felis chaus: https://www.gettyimages.com.au/detail/photo/side-view-of-cheetah-walking-on-field-velavadar-royalty-free-image/1320024025?adppopup=true and https://www.istockphoto.com/photo/jungle-cat-felis-chaus-blackbuck-national-park-velavadar-bhavnagar-gujarat-india-gm1163103403-319260219 and https://www.naturepl.com/stock-photo-jungle-cat-felis-chaus-at-night-kanha-national-park-and-tiger-reserve-nature-image01622905.html and https://www.naturepl.com/stock-photo-jungle-cat-felis-chaus-at-night-kanha-national-park-and-tiger-reserve-nature-image01622899.html and https://www.khaosodenglish.com/news/bangkok/2017/02/16/swamp-cat-back-from-the-dead-rediscovered-in-chiang-mai-jungle/ and http://www.catsg.org/index.php?id=114 and https://animalia.bio/jungle-cat and https://www.facebook.com/cwsindia/photos/the-jungle-cat-is-a-medium-sized-cat-native-to-the-indian-subcontinent-and-other/2885946491441428/ and https://www.francisjtaylor.co.uk/product/jungle-cat/ and https://www.123rf.com/photo_85736411_jungle-cat-felis-chaus-walking-ranthambore-national-park-rajasthan-india.html and https://www.alamy.com/stock-photo-jungle-cat-felis-chaus-walking-ranthambore-national-park-rajasthan-95858779.html and https://www.francisjtaylor.co.uk/product/jungle-cat/ and https://www.shutterstock.com/nb/image-photo/jungle-cat-felis-chaus-wallking-across-1423398455 and https://www.alamy.com/stock-photo-jungle-cat-felis-chaus-walking-on-fallen-tree-trunk-dry-season-april-125610085.html and https://www.mindenpictures.com/stock-photo-jungle-cat-felis-chaus-walking-towards-a-dirt-track-madhya-pradesh-naturephotography-image00541439.html and https://www.gettyimages.com.au/detail/photo/side-view-of-cheetah-walking-on-field-velavadar-royalty-free-image/1320024025?adppopup=true and https://www.natureinstock.com/search/previewmodal/jungle-cat-felis-chaus-at-night-kanha-national-park-and-tiger-reserve/0_12524992.html?dvx=895.

Posted by milewski over 2 years ago

The first in the following series of three is an excellent photo of Panthera tigris: https://www.inaturalist.org/observations/37093122.

It shows, inter alia, the following:

The striping on the tiger, so effective as disruptive colouration (camouflage), is far from uniformly applied to the whole figure.

Note how intense the striping is on the hindquarters and tail, compared to the forequarters with their sparse striping.

Note the lack of any caudal flag, in contrast to e.g. Panthera pardus.

Note the horizontal pattern on the legs, particularly the posterior aspect of the forelegs.

Posted by milewski almost 2 years ago

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