Eye Black: What Works for Football Players Works for the Cheetah

I remember when I was younger I would always wonder why baseball and football players wore black paint under their eyes.  My dad told me that the "eye black" was to help to reduce the glare that their eyes received from the sun.  Although some people seem to disagree whether or not this is effective for human sports players, it seems that several animals have evolved a similar pattern on their face!  But before we dive in, a very special thanks to Anne Price for her help with this post!

I imagine that there are a number of stories told by native peoples of Africa that explain the tear marks of the cheetah, which you can see in the picture above.  The one that I have heard before (which you can read by clicking HERE) tells of the cheetah being told by lions that she was not a cat, and instead was a dog.  The cheetah then went to talk with the wild dogs.  But the wild dogs also kicked the cheetah out, saying that she was a cat and not a dog.  The cheetah, sad with the fact that she did not seem to belong to either group, cried so much that the tear marks were burned into her face.

Some scientists believe that these black marks, which they called "malar stripes" or "malar marks," actually evolved to help the cheetah see in sunny conditions, by reducing glare and keeping the sun out of its eyes.  This would have been the original "eye black," a phenomenon whose roots extend back much further than the origins of baseball or football.  I was surprised when I was researching this natural eye black, as I thought it was a commonly cited fact that cheetahs had this eye black to reduce glare.  However, many of the sources just mentioned the malar stripes, and didn't actually address their function.  

In the book "Big Cat Diary: Cheetah," Jonathan and Angela Scott propose an alternative hypothesis.  Though they do mention the anti-glare hypothesis, the Scotts suspect that a more likely alternative is that the tear-marks serve to "accentuate facial expressions," which they say would be an "important consideration in social interactions with other cheetahs."  The tear marks, "along with the growls and hisses that are an important part of a cheetah's defensive repertoire," might "deter competitors from approaching."  While this is well and good for the cheetah, and is likely at least part of the reason why the cheetah has the malar stripes, I have a difficult time believing that this is the only reason why some animals evolved the stripes.  We will get to my reasoning in a second.

What I find really interesting about these stripes is that they are unique to the cheetah in the cat world.  The cheetah, as is mentioned in the African story above, is a very unique cat, different in many ways from others felines.  One way in which the cheetah is different is that it hunts primarily during the day, and is much less a nocturnal animal than most cats.  If you look at the eye of your house cat, look for two things.  The first is the size of the eye.  Though the cat is quite small compared to you, Mr. Whiskers has eyes that are only a bit smaller than yours!  Second, look at the pupils.  Unlike the pupils of humans that stay circular regardless of the level of dilation or constriction, cat pupils constrict to tiny diamond slits, but dilate to large circles.  This is because most cats are active at night and during the day, and in order to protect their eyes in a variety of light conditions, they have evolved very mobile pupils.  

My cat Chimney.  Notice her slit pupils.  And the One Direction pillow in the background.  Photo Credit: Dani Neher

The cheetah does not have diamond pupils, and instead has round pupils.  This stems from the fact that cheetahs are primarily diurnal, and usually hunt during the day.  According to the Scotts, "just like birds of prey," cheetahs have a "patch of highly light-sensitive cells on the retina known as the fovea."  These cells provide the cheetah with the "most precise visual perception," and enables them to "spot prey from as far away as 5 km (3 miles)."  I find this comparison to birds of prey interesting, as both the cheetah and the prairie falcon, another animal with malar stripes, would have the need to be able to spot prey from a great distance, and in sunny conditions.  This large North American falcon has very similar streaks of brown feathers beneath its eye, which flow down the face.  According to "The Prairie Falcon" by Stanley Anderson and John Squires, the "black mustachial stripes near the eyes...may further reduce glare."

This idea is supported by other bird of prey experts, such as Anne Price, the Curator of Raptors at the Raptor Education Foundation in Colorado.  Eager to learn more about the similar stripes on the face of the prairie falcon, I emailed Anne, and here's what she had to say:

It’s meant to reduce glare by having the sun strike or be concentrated in the area beneath the eye, leaving the area above in proper contrast.  The black lines under the eyes of cheetahs, most falcons (gyrfalcons and merlins being notable exceptions) and even flickers have malar stripes, though in flickers they serve as signals for courtship, not for better visibility of prey species!

Other falcons that have the malar stripe include the American kestrel....

....and the peregrine falcon.

Not all falcons have the malar stripe, however.  As Anne mentioned above, gyrfalcons and merlins are notable falcons that don't have the malar stripe, but here is another one: the African pygmy falcon, the smallest of the African raptors!  This is a picture that I took of one at the Denver Zoo.

Furthermore, the black streak under the eye is also seen on the face of many species that the cheetah preys upon.  According to the cheetah section in "Wild Cats of the World" by Mel and Fiona Sunquist, 91% of cheetah kills in the Serengeti are Thomson's gazelle.  In Kruger National Park, 68% of kills were the impala, and in other areas such as Botswana, springbok are an important part of the diet as well.  73.9% of the kills made by cheetahs in Nairobi National Park were Thomson's gazelle, Grant's gazelle, and impala.  As you can see in the pictures below, all of these antelope have that black streak under their eyes, though it is less pronounced in the Grant's gazelle and impala than it is in the Thomson's gazelle.  One of the biggest reasons for markings on an animal that don't aid in camouflage or sexual selection (i.e. differences between male and female that are used to attract a mate) is to help with species differentiation, so that they don't waste valuable time and resources attempting to breed with each other.  But since all of these antelope have the black tear marks, as well as both genders of the species, that's probably not the role that the tear marks were playing.*

A Cuvier's gazelle at the San Diego Zoo, which also has very similar malar stripes.

A Speke's gazelle at the San Diego Zoo, yet another gazelle that has the same sort of malar stripes.

It is these antelope that make me wonder whether the cheetah evolved the malar stripe to "accentuate facial expressions," as proposed by the Scotts.  In my experience, antelope such as the Thomson's gazelle don't really go around making faces at each other, at least nowhere near as much as cats do.  The fact that both the predator and prey in this scenario possess the same adaptation makes me wonder whether coevolution has occurred.

Coevolution is a biological phenomenon in which the evolution of one animal influences the evolution of another.  A classic example would be flowers and the insects that pollinate them.  Flowers need their pollen to be carried to other flowers in order for reproduction to occur.  Oftentimes, these flowers employ the use of bees and other insects to do the job for them.  But to make it worth their while, the flowers supply the insects with a delicious meal of nectar.  When the insects land to suck up the nectar, they also pick up some pollen.  Then, when they fly off to another flower to indulge in some more nectar, they unknowingly deposit some of the pollen, and simultaneously pick up some more!

I find it possible that coevolution has occurred in regards to the cheetah and its prey.  Imagine if a certain lineage of cheetah evolved that had the black tear marks beneath their eyes, while the rest of their cheetah brethren did not have this black streak.  If the black streak did help them see their prey a little better by reducing glare, then perhaps these cheetahs were more successful hunters, and produced more offspring because of it.  Suddenly, the gazelles and impala are faced with a formidable foe that can suddenly see farther than they used to be able to.  In order to compensate, it's possible that the antelope who also had black streaks under their eyes were able to see farther as well, and spot the approach of a predator from a greater distance.  Strangely enough, I haven't been able to find anything anywhere suggesting that coevolution might have occurred here, so who knows!  I'm just throwing this out there, I'm not saying that's definitely what happened, but it's a prospect which I find intriguing and thought worth sharing with all of you.

*To read more about species differentiation and the role it plays in the success of biological organisms and species diversity, click HERE to learn more about the effects of logging on a type of fish called cichlids.

Works Cited:



An interview with Anne Price.

Anderson, Stanley H., and John R. Squires. The Prairie Falcon. University of Texas Press, 1997. (accessed December 16, 2013).

"General Information About the Cheetah." Cheetah Conservation Fund. http://www.cheetah.org/?nd=general_info (accessed December 16, 2013).

"How The Cheetah Got Its Tears." Cheetah Conservation Fund. http://www.cheetah.org/?nd=story_cheetah_tears (accessed December 16, 2013).

Stokes, Donald, and Lillian Stokes. The Stokes Field Guide to the Birds of North America. New York: Little, Brown and Company, 2010. (accessed January 23, 2014).

Eyes on Ears and Mouth on Toes

Despite the clever if misleading title, we will not be talking about mouths on toes today (although many creatures such as butterflies can taste with their feet).  I just said that to make it sound like the line from the classic song "Head, Shoulders, Knees and Toes" by Bob Dylan.  Instead, we are going to be talking about eyes on ears: eyespots, at least!

A picture of one of the Amur tigers at the Denver Zoo.  See those white bars surrounded by dark fur on the ears of the cat?  Those are the topic of today's discussion.

On the cover of the August/September issue of the National Wildlife magazine, there was a picture of a drinking bobcat, its ears folded back in the posture that some refer to as "airplane ears."  On both of its ears were two white bars that made the ears look a lot like eyes.  I never really paid attention to this pattern on the coat, but once my friend Aidan Cook pointed it out, it got the proverbial gears going.  I remembered that servals also had the eyespot-like patterns as well, but did other cats?  Turns out a lot of them do, with just a few shared throughout the post.  Notice how defined the eyespot is in both the bobcat (top) and the serval, below.

To learn more, I consulted my "Wild Cats of the World" book by Mel and Fiona Sunquist.  The authors state that many cats have this pattern on their ears, "almost as many species" have the ear eyespots that are "poorly defined or absent."  One of the many examples that they include is the lion.  As you can see in the pictures below, lions do have this pattern to a certain degree, but nowhere near as derived as in the serval or the bobcat.  Below we have pictures of a young adult male lion, two of females, and one of a cub, and you can see that none of them have a very well defined eyespot.

Mountain lions also generally don't have it as well defined.  It seems like some mountain lions really don't have that much black on their ears at all, and some have a higher degree of black and white.  Presumably, whatever the function the eyespot serves in other species, it is not as important for the mountain lion, and natural selection therefore does not favor it highly one way or another.

It's a little tough to tell in the picture below, but the sand cat is another one of those cats that has a poorly defined eyespot.

Cheetahs also don't have terribly well defined eyespots.

Yet another cat that does not have very well defined eyespots, the ever fantastic Pallas cat!

I thought I had read somewhere that the eyespots served to help communicate between individuals when they were hunting.  This doesn't make that much sense, though, because most cats are solitary individuals, with the main exception being lions, and we already noted that their eyespots are not quite as specialized.  The Sunquists state in their book that the exact function of the eyespots is unknown, although some scientists believe that they serve as a "follow me" signal to their young, which "may be especially important in low-light conditions."  I assumed that this might mean that the young cats wouldn't have the eyespots, but this is clearly not true, as you can see the photograph of Sochi, the new male Amur leopard cub at the Denver Zoo.  There, you can see that Sochi (named after the Russian city that is holding this years Olympics) also has the ear spots.  So while this doesn't necessarily support the idea of a "follow me" signal to the young, it doesn't really not support it either: it's just something interesting that I wanted to point out.

We already talked about how tigers have a pretty well developed eyespot, but here are two more pictures of tigers to drive the point home.

I can't remember for certain if the picture below was a bobcat or a lynx, but I am pretty certain it is a bobcat, looking at the size of the feet.  (Lynx spend a lot more time in the snow, and therefore have larger feet, a snowshoe-like adaptation to keep them from sinking in.)  This cat, one of many at the Wild Animal Sanctuary, seems to have much smaller feet in proportion to the rest of the body.  Regardless, you can see the well defined eyespots.

The snow leopard, one of my favorite cats, has well defined eyespots as well, which you can kind of see in both of these pictures.

Photo Credit: Masaki Kleinkopf 

The fishing cat is another cat that has these well defined eyespots.

And finally, the Canadian lynx, much like its bobcat relative, also has pretty well defined eyespots!

Works Cited:

The First Zoo

Where and when was the first zoo?  Of course, depending on your definition of the word "zoo," different people might have different answers to this question.  The oldest known zoological collection has been excavated at Hierakanopolis in Egypt, dating to around 3500 B.C.  So far, the remains of numerous animals have been uncovered there.  According to one source, 112 different animals have been found, including elephants, wildcats, hippos, cows, hartebeest, baboons, dogs, and an Aurochs, the subject of an Animal Spotlight awhile back!  (Click HERE to check it out!)  Since my source is a few years out of date, it is entirely possible that more discoveries have been made there since then!  Despite all of this, most scientists don't believe this is the first "zoo," at least not by modern definitions, a place where anyone can come and look at these animals.  It is thought that the site at Hierakanopolis is more of a private collection kind of thing.

Most people seem to agree that the first public zoo was created by Queen Hatshepsut, a zoo that people today would define as a zoo.  Not a lot of data (at least not that I can find) exists to tell us what sort of animals Hatshepsut kept in her zoo.  Some of the animals that we do know were imported include rhinos, cattle, giraffes, leopards, monkeys, and hounds.  Presumably, some of the other animals that we mentioned before made it into the zoo, as well.

What other animals could have made it into the zoo?  A lot of this is speculation on my part, but based on the animals of the surrounding area, here are some animals that I think likely made it into these zoos:

• Dromedary camels
• Jackals
• Hyenas
• Crocodiles
• Cheetahs
• Lions
• Jungle cats

There are many reports of other important Ancient Egyptians possessing captive lions, and it seems like captive lions would be a pretty impressive display of one's power.  I find it very likely that both cheetahs and jungle cats were members of the zoos, as well, as cheetahs (generally fairly docile around humans, especially compared to other large African cats like lions and leopards) have been domesticated a number of times throughout history.  These domestic cheetahs were used by many people, including Akbar the Great of India (who was thought to have around 9,000 cheetahs: not to be confused with Admiral Ackbar), for hunting, both for sport and for sustenance.  Jungle cats, too are reported to have been domesticated by the Ancient Egyptians in order to hunt water birds.  Mummified remains of the jungle cat are sometimes found in ancient tombs, put there by the burial people.  (I don't actually know if they have a special name or something).  

This was the birthday post of Grace Albers! Happy birthday, Grace! If you have a birthday coming up, just email me the date at cuyvaldar123946@gmail.com with the date and your favorite animals, and I will do my best to get a post in! And if you like what you are reading, please feel free to follow us here or via Facebook!

Luxor on Dwellable

17 Truths Episode 1: The Cheetah

If you haven't seen the "True Facts" video series, then you are missing out.  Assuming, of course, that you have a good but slightly inappropriate and sarcastic sense of humor, and are not young enough that your parents will become angry with me if they find out where you found out about them.  That is why I am not providing a link to them here.  Anyways, I find them absolutely hysterical, and was quite eager to try my own hand at one!  One of my favorite animals is the cheetah (which is pretty obvious for people who are regular readers of my blog), a sentiment which is shared by people all across the world.  There are many interesting things about the cheetah, and many questions that people have about this fantastic and acrobatic feline.  So I thought that, for the first True Facts-esque video, I could make it about the cheetah!  It didn't hurt that I had a bunch of pictures of it, as well as a video!  However, I did use a few photos from some friends of mine, so I am going to give photo credit to Grace Albers and Shira Wood-Isenberg!  I would also like to give Joseph M. Roessler credit for the fantastic music that I used in the video!  It was both composed and performed by him!  HERE is a link to the song (called Dream Waltz), HERE is a link to some more of his music, and HERE is a link to his SoundCloud!  Enjoy!  And, of course, we have to have a link to the video!

And here we have some of the pictures featured in the video!  Enjoy!

This is the birthday post of Govind Kudva!  Happy birthday, Govind!  If you like what you are reading, please feel free to follow us here or via Facebook!  And remember, if you have a birthday coming up, just email me the date at cuyvaldar123946@gmail.com with the date and your favorite animal, and I will do my best to get a post in!

Animal of the Day: Addax

The Addax (Addax nasomaculatus) sometime called the screwhorn antelope, is a "Critically Endangered" member of the group of animals known collectively as the antelope.  The addax is found in the Sahara desert.  The Addax has been extirpated, or made regionally extinct, in the countries of Egypt, Algeria, Western Sahara, and Sudan.  Nowadays, the Addax can only be naturally found in the countries of Chad,  Niger, Mauritania, and has been reintroduced into Morocco and Tunisia.  The Addax has earned its "Critically Endangered" status due to the immense and very frequent hunting of its horns, and is still often hunted on game reserves in the United States.  The meat and leather obtained from the Addax are also highly prized.  Their diet consists of primarily grass, as well as the leaves of various shrubs.  Rarely drinking, they instead gain most of their moisture through the plants that they eat.  The Addax is a slow moving animal, leaving it vulnerable to attacks from cheetahs, leopards, lions, African wild dogs, and humans.  The calves can also be killed by servals, caracals and hyenas.

There is also a Spanish motorsport team named the Barwa Addax Team, but I was unable to ascertain whether this team was named after the animal or not!
 

Animal of the Day: Beira Antelope

The Beira Antelope (Dorcatragus megalotis) is a small, 1.5 to two foot tall (at the shoulder) antelope that is native to the arid and mountainous regions of Djibouti, Somalia, and eastern Ethiopia.  The males have straight, short horns, and they are currently listed as "Vulnerable" by the IUCN.  The captive breeding program in Qatar, at the Al Wabra Wildlife Preservation center, reached its height in 2005 when it had 58 Beira Antelope.  The center has around 2,000 animals, including gerenuk, Somali wildass, sand cats, and cheetahs.  According to their posters on their website, they also have other felines, including the African wildcat, the caracal, the jungle cat, and even a king cheetah, which is a melanistic form of the regular cheetah.  As well as having many different types of felines, they do have lots of ungulates, as well as many types of birds, and some reptiles to boot.

HERE is the page on the Beira Antelope from the Al Wabra Wildlife Preservation center's website.

Zoo Spotlight: The Living Desert

So at least a few times now, I have used pictures from a zoo we went to in Palm Desert called "The Living Desert."  An awesome zoo, this place (clearly) focuses a lot more on the desert animals of the world, and introduces you to a number of animals that you immediately recognize, and a number of animals that you might not otherwise be able to see at another zoo.  I thought I could share some of the pictures that I took at this exciting place, and recommend it to one and all as an exciting place to visit if you ever pass by that area!

Sand cat

Let's start off with some of the animals that you might not be able to see at most other zoos.  As regular readers know, I am a pretty big fan of cats, and The Living Desert definitely had its fair share!  For example, the "Near Threatened" sand cat (Felis margarita), the only cat that is found primarily in the desert.  One of my favorite small wild cats, the sand cat is found in the deserts of Africa and the Middle East.

Sand cat

Besides the sand cat, The Living Desert also has a few other small cats, including the Arabian wild cat, one of the many sub species of the wild cat, Felis silvestris.  Unfortunately, this little guy was asleep so I didn't get any pictures, but I did get pictures of two of the other smaller felines: the serval, and the bobcat, each of which we have done an Animal Spotlight on.  The serval is native to Africa, while the bobcat lives all over North America, in both forests and deserts.

Sleeping serval

Bobcat on the prowl

Bobcat....stretch!

Other, larger cats can be found at The Living Desert, as well, including the jaguar and the mountain lion (both of which I got no pictures of), as well as the cheetah.  We saw two or three cheetahs, but they were all doing what cats do best: sleeping! 

Sleeping cheetah!

Another very interesting thing about the zoo is the vegetation.  Many people simply pass over it: but if you do stop to take a look at it, you might notice something interesting: a whole bunch of the plants, both in and out of the exhibits, are very prickly!  This is because the people at The Living Desert have done their best to make the vegetation in their exhibits as accurate as possible.  Pay special attention to the trees once you reach the large exhibit with both giraffes and kudu, a type of African antelope.  These incredibly spiky trees are called acacia trees, and these trees are one of the reasons why the giraffe has such an incredibly long tongue.  I've been able to see this tongue first hand on numerous occasion at the Cheyenne Mountain Zoo, including the last time I went with my friend Masaki Kleinkopf, as you can see in this incredible video.  The giraffe has been forced to evolve its incredibly long, prehensile in order to circumnavigate through and around these spiny branches in order to reach the leaves. 

Look at those spikes on those acacia trees!

A picture of myself feeding the giraffes at the Cheyenne Mountain Zoo

Grazing kudu

Another one of my favorite things at The Living Desert was the Miriam U. Hoover Discovery Center.  Indoor and air-conditioned (which, trust me, was very refreshing after being in a desert for a while!), the Discovery Center had a number of things for younger kids to do, but it was definitely worth stopping in, because they had an exhibit talking about the Pleistocene (2.5 MYA - 12,000 years ago) residents of California!  Here are what some of the coolest fossils were.

Mounted giant ground sloth skeleton

A full skeleton of the eight-foot-tall giant ground sloth.  The relationship between extinct South American ground sloths and the extant tree sloths was one of the most important things that influenced Charles Darwin into his Theory of Evolution, more so than the case of the Galápagos finches that most textbooks cite.  During the Great American Interchange, at a time when many South American species were going extinct due to competition from animals coming down the Isthmus of Panama from North America (like Thylacosmilus), the giant ground sloths were actually able to move the other way, with remains being found even as far north as Alaska.  

The skull of Panthera atrox, the North American lion

A skull of the North American lion (Panthera atrox), as well as a skull from Smilodon, colloquially known as the "saber-toothed cat."

The skull of Smilodon

Skulls of Camelops (a type of camel); a dire wolf (Canis dirus), a significantly larger relative of the extant gray wolf; and the Teratorn, one of the members of the family Teratornithidae, a group of birds of prey that lived in North and South America, and includes the largest flying bird known, Argentavis.  Finally, there was a life-sized picture of a mammoth on the wall with a fossil tusk sticking out which was pretty cool as well!

The skull of Camelops

The skull of the dire wolf

The skull of the Teratorn

A size comparison of a mammoth and a human, myself

Now, back to the living!  Here are some more pictures of some of the really cool animals that we saw!  

The "Critically Endangered" addax (Addax nasomaculatus), native to the Sahara Desert

The "Endangered" African wild dog (Lycaon pictus), native to (you guessed it) Africa

American badger

Bighorn sheep

Burrowing owl

Dromedary camel

Caracara

Sleeping fennec fox

Another sleeping fennec fox

Giant tortoises eating

Mexican wolf

Another Mexican wolf.  Despite the fact that this wolf looks like it is snarling, it actually wasn't!  I don't actually know what was going on!

A Mexican wolf running

Pronghorn

There were also tons of lizards running around all over the place!

There was also a really cool, huge, giant train set!  Here are a bunch of pictures of it!

Incredibly detailed: the Monticello vineyards!

Incredibly detailed: Mount Rushmore!

 

 

 

 

 

 

So would I recommend The Living Desert to anyone who is going to be in the area?  You bet I would!  Not only is it an excellent zoo, it gives the visitor an interesting and often difficult-to-find view of desert life from around the world!

South Palm Desert on Dwellable