Penguin Party: The Korora and the Magellanic

Today's post is devoted to two of the seventeen (debatably a lower number) of the extant penguin species, the Korora (commonly known as the little blue penguin, the blue penguin, the little penguin, or the fairy penguin), and the Magellanic penguin.  What's the connection with these two penguins?  Well, not really anything, except for the fact that we had just talked about the Korora in a post a few weeks ago, and I had found a few funny videos of both the Korora and the Magellanic! 

The Korora is actually believed to be fairly closely related to the Magellanic penguin, compared to most of the rest of the penguins.  Despite the differences in their genus (the Magellanic belongs to the genus "Spheniscus" and the Korora to the genus "Eudyptula,") most scientists believe that the Eudyptula penguins (only one extant, but likely extinct ones) were the last ones to diverge from the Spheniscus genus. 

As we talked about a few weeks back, the Korora is labeled as "Least Concern" by the IUCN, and inhaibts Australia and New Zealand, as well as a few other random islands in the vicinity.  Interestingly enough, the Korora has also been reported in Chile and South Africa, although the probability of these animals being vagrants (essentially, lost) is quite high.  However, most penguinologists are certain that many populations of penguins started out as vagrants, so who knows!  It is how they would get from one place to another. 

The Penguin Parade (see below) is a major tourist attraction.

The penguin parade.  Photo Credit Mark and Julie Neher

HERE is a link to a clip talking a bit about the Penguin Parade.  The clip talks a bit about the work done by the rangers and scientists regarding the Korora, including ranger Ashley Belsar.  For over thirty years, since 1968, this research team has been recording information about the penguins as they come ashore.  An interesting statistic that I learned from this video is that the average penguin spends about 80% of its life in the ocean!

And for those of you who want something a bit more"cutesie," HERE is a video of Cookie, the Korora, being tickled by humans at the Cincinnati Zoo in Ohio!

Native to the South American countries of Chile, Argentina, and occasionally Brazil, the Magellanic penguin is one of four of the Spheniscus genus of penguins, including the African, Humboldt and Galápagos penguins.  Labeled as "Near Threatened" by the IUCN, somewhere in the neighborhood of 40,000 of these penguins are killed each year by oil spills, which has resulted in their decreased IUCN status.

Next, we have two amusing Magellanic penguin videos.  The FIRST is of a Magellanic on a plane, and the SECOND is a trio of Magellanics who accidentally knock over the camera that is filming them.  Enjoy!

Now, we have a few really cute pictures of some of the Magellanic penguins from Sea World: Orlando in Florida!  The second two photos are from a publicity thing where some people from Sea World: Orlando brought some Magellanics to the Star newsroom!  How cute!

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Perfume-Loving Lions and Record-Breaking Cheetahs

Two interesting pieces of feline-news for you today!  The first actually takes place at the Denver Zoo!

13 year old male lion named Krueger seems to really like "Obsession," by Calvin Klein!  Apparently, if the perfume (or is it cologne?  Man-fume?) is sprayed inside of his enclosure, he goes to the same spot and "rubs his cheek on it."  When you actually think about it, it totally makes sense.  Perfumes and colognes are supposed to attract people due to pheromones inside of them.  Animals also use pheromones, mostly to communicate.

Has a cat ever done this to you?  Scent glands in the cheeks of cats (as well as in their paws) contain pheromones, used in communication.  Each cat has a unique scent, and it rubs off when they rub into things like this.  So when your cat greets you, it is partly due to affection, and also partly due to the fact that they are really marking you as their territory.  At least they aren't peeing on you!  So this explains why Krueger would rub his cheeks against the spots of Obsession sprayed around his enclosure.

Interestingly, the lions seem to enjoy Obsession more than other perfumes, and not all of the lions were attracted to it: only half of them were, in fact!  Emily Insalaco, an employee at the Denver Zoo, thinks that the lions like this particular cologne more than others due to the presence of cinnamon, which the lions have seemed partial to in the past.  If you want to see a video containing more information, click below.

http://www.9news.com/news/story.aspx?storyid=146948&catid=188


Next up is Sarah the cheetah, one speedy demon from the Cincinnati Zoo in Cincinnati, Ohio!  Multiple times has this amazing cat beaten the world record for the 100 meter dash, and once even twice in the same day!  The first link below is from Sarah's first world record break, where she broke the world record twice in one day in 2009.  The second clip below is from more recently, when Sarah yet again beat the record, in June of 2012. 


http://www.thetravelalmanac.com/lists/videos/animals-speed.htm

http://news.nationalgeographic.com/news/2012/08/120802-cheetah-sarah-cincinnati-zoo-fastest-record-science-usain-bolt-olympics/

Spring Valley on Dwellable

Simba, Pumbaa, and Other Swahili Names From "The Lion King"

Recently I decided to learn a bit of Swahili, and I have stumbled across a few things that I thought were quite interesting!  For instance, did you know that "Safari" meant "Trip" in Swahili?  I certainly didn't!  And the old movie entitled "Hatari!" actually means "Danger!" in Swahili!  Who knew! 

As I continued to learn more, I came across something else interesting.  As I was learning the animal names, I found that "Duma" meant "Cheetah," which excited me, as one of the main cheetah stars from BBC's "Big Cat Diary," one of the later seasons, is named Duma.  Next, I found out that "Chui" meant "Leopard...." and guess what?  There was a leopard named Chui, too!

Then, I found that "Simba" meant "Lion."  There was, of course, a lion that went by the name of Simba, in the first season of Big Cat Diary, I believe.  I had just assumed he was named after Simba from "The Lion King," which is still a possibility, but it could really go either way.


But I think it clear where the name of "Simba" came from for the Lion King.  As a matter of fact, many of the characters have names that mean something else in other languages.  For example, Ed, the hyena, is actually short for "Edward" in English.  Below is a list of others.

1. Nala - Gift
2. Pumbaa - Simpleton
3. Rafiki - Friend
4. Sarabi - Mirage
5. Shenzi - Uncouth
6. Sarafina - Bright Star
7. Banzai - Skulk, or Lurk

Top Ten: Extinct Sea Monsters (Part 1 of 5)

Since ya'll kinda get gypped on Wednesdays with the "What Is It?" challenge, I decided that, when I do do the challenge, I will also include a "Top Ten" list.  I mean, come on now, who doesn't like lists?  I know some of my friends would be absolutely and completely lost without them!  So for today's "Top Ten," we are going to take a look at some of the world's most amazing, extinct sea monsters.  This is also up for debate, so if you disagree, just give me a holler!  Also, they are not in any particular order, I just kind of threw them all in there!  So without further ado, here we go, with our "Top Ten:  Extinct Sea Monsters!"

1.  Megalodon - This gigantic relative of the extant great white shark was thought to be simply massive: perhaps even sixty feet in length!  Living the world over, Megalodon stalked the seas during the Miocene and Pliocene Epochs, and only died out during the current Pleistocene Epoch, around two million years ago.  It is thought that Megalodon evolved to such gigantic proportions in order to be able to attack the massive whales that had started to evolve in the cooler seas of the Miocene and Pliocene.  Remember now: if it's a shark, then it's a fish!

A tooth fragment from Megalodon at this excellent restaurant called The Crab Shack on Tybee Island off of the coast of Savannah, Georgia. 

2.  Basilosaurus - A massive, predatory whale (and, therefore, a mammal) that cruised the seas in the Late Eocene Epoch, 40 to 34 MYA, fossil discoveries of this massive animal were reportedly so common in the southern United States during the early 19th century, that bones of Basilosaurus would be used as furniture!  It was first discovered in Louisiana, and is the state fossil of both Mississippi and Alabama.  Basilosaurus has also been found in Egypt and Pakistan.  At around sixty feet in length, the same estimated length of Megalodon, Basilosaurus is thought to have been the biggest creature alive at the time.

COMING UP:

3.  Liopleurodon
4.  Shonisaurus
5. Elasmosaurus
6.  Dunkleosteus
7.  Archelon
8.  Leedsichthys
9.  Tanystropheus
10. Tylosaurus

This post is part of the "Top Ten: Extinct Sea Monsters" series.  For the rest of the posts in this series, click HERE. 

Animal Spotlight: The Okapi

For years, Europeans who traveled to Africa heard tell of a mysterious rainforest animal that they came to refer to as the "African Unicorn."  Apparently, Sir Harry Johnston, the British governor of Uganda, rescued a small group of the native inhabitants, often called the pygmies, from a foreign show person, who, sadly, was most likely going to use his abductees for a circus or freak show.  Upon their rescue at Johnston's hand, they repaid him by giving him information about the animal.

Now we know the animal as the okapi, or Okapia johnstoni, named in honor of Sir Harry Johnston.  Despite the zebra-like stripes on its tail, the okapi is not all that closely related to the zebra, and is actually a very close relative of the giraffe.  Although they may not look super similar, they both have ossicones on their head, similar to the base of DEER antlers.  Ossicones are not only possessed by both the okapi and the giraffe, but also by extinct relatives of both, such as Sivatherium and Climacoceras.

The okapi is listed as "NEAR THREATENED" by the IUCN.  Honestly, I was surprised that it wasn't at least listed as "VULNERABLE," and "ENDANGERED" or worse would not have surprised me at all, given its reclusive nature, its beautiful pelt, and the very fact that humans didn't have much proof of its existence until 1901, when Sir Henry Johnston sent back a carcass to England.  I suppose, however, that its reclusive nature likely helps it to evade human influences a great deal, coupled with the fact that the rainforest that it inhabits is not too heavily tread.  And I guess the fact that it was really made known to science only a little more than one hundred years ago couldn't have hurt either, as it would be soon entering into an age when nature was offered greater protection than in the 1800s. 

Like the COELACANTH and THE MOUNTAIN PYGMY POSSUM, the okapi is often referred to as a "LIVING FOSSIL."  Its habitat consists of montane rainforests in the Central African Republic (CAR) and the DEMOCRATIC REPUBLIC OF THE CONGO (DRC).

The Fox's Animal Magnetism

For a while now, it has been thought that birds could see the magnetic field, in order to help them migrate.  It has been hypothesized that, when they are facing north, they can see a little blurry patch at the bottom of their eye.  If they are facing east or west, then they can't see the patch, so they know where to put the patch in their field of vision to get where they want to go.  Recent research by a Czech team of scientists seems to indicate that the red fox can also use the magnetic field, but for a different purpose: hunting.

The red fox (Vulpes vulpes) ("Least Concern" by the IUCN) has the largest geographical distribution of any member of the Carnivora, with habitat on all of the continents except for South America and Antarctica.  In North America, it inhabits the United States and Canada, in Europe and Asia it lives almost everywhere, and in Africa it lives in Morocco, Algeria, Tunisia, Egypt, Sudan, and Libya.  Not only does it possesses the range shown in the map below, it has been introduced to Australia, where, like the Dingo, it poses a threat to native species.

The red fox hunts by leaping up into the air, and coming down right on top of its prey, literally (for the prey, at least) appearing out of nowhere.  But how to pinpoint its jump?  The answer lies in the magnetic field, which is visible to the foxes.  But how does this work?  Out of all of the explanations set forth by various journals and such, I thought the explanation from Nature was easiest to understand.  Here's what they have to say:

"Think of a laser pointer attached to you that always points slightly downwards in the same direction. Now think of some object on the ground. If you walk towards the object until the laser spot is on top of it you know that object is a set distance away."

Generally, it was thought that foxes would pinpoint their location solely using their very acute sense of hearing.  But then the Czech team found that, when the red fox was leaping in a northerly direction, 74% of the attacks were successful, while the leaping attacks in other directions had the success rate of a mere 18%.  That's a very big difference, and seems to point to the magnetic field theory.

A picture of the red fox outside of the house that our friends the Beckleys rented in Breckenridge one summer.  Awesome place to stay, especially if you are looking to escape the summer heat!  Photo Credit: Julie Neher

East Breckenridge on Dwellable

Propleopus, the Carnivorous Kangaroo

Imagine you are on a safari to the Masai Mara National Reserve in Kenya.  If you timed your visit right, then the Mara is inundated with wildebeest and zebra, as well as numerous other herbivores.  You will probably see a number of carnivores as well: cheetahs, leopards, lions, and especially hyenas.  What you probably don’t realize is that most places aren’t like this.  The Masai Mara has one of the highest predator populations seen in Africa, due in large to the great number of prey animals available for a meal.  Regardless, you are forced to acknowledge that there are a great many more prey animals than there are animals to prey upon them. 

                This is known as the predator/prey ratio, and it can be seen all over the world, and can also be seen in the past.  While hundreds, sometimes thousands, of fossils of a single herbivorous dinosaur can be discovered, it is far more rare to unearth the remains of a predatory dinosaur.  But why is there this unbalance between predators and their prey?  Well, let’s take a look at a continuous, cyclical event that takes place in a period of 9.6 years in the wilderness of Canada, that should be able to shed some light on the situation.

                At the beginning of the almost-ten year cycle, we see a sharp increase in the number of hares.  When food is plentiful, these hares often produce two to three litters of around 12 leverets (baby hare) each.  After their numbers reach their limit, their population density reaches around eight hare per football field.  At this time, the hares have eaten all of the edible material they can reach.  Not only are they out of food, but the plants that they feed upon begin to create bitter chemicals in their leaves and edible parts, that keep the hare from digesting the plant material very efficiently. 

                While the hare population is flourishing so, the hare’s predators find an especially easy time of it.  Owls, wolves, and foxes all flourish, but one predator does particularly well: the Canadian lynx.  Hares consist between 40 and 85 percent of the average lynx’s diet, and they generally kill two hares every three days.  With such an explosion in hare numbers, all of these predators flourish, successfully raising more owlets, kits, and cubs.  However, shortly after the plants begin to release the anti-digestion chemicals, the hare populations tank.  With not enough food, many of the animals die off.  Then, a year or two after the hare die-off, the lynx also experiences a massive fall in numbers.  With the lynx no longer over hunting the hare, and the predator/prey ratio returned to normal, the hare starts the cycle all over again. 

                While this cycle seems to be a healthy part of the Canadian ecosystem, in other places, a rapid rise in the number of predators or prey could be disastrous.  Therefore, nature has made it so that, in a healthy ecosystem, the prey animals vastly outnumber the predatory animals.  But how does all of this tie into kangaroos?  We will get back to that in a minute.  First, let’s take a look at an extinct, 26,000 year old relative of today’s rat kangaroo. 

                First described by Australian zoologist Charles De Vis around the turn of the century, the holotype of Propleopus at first remained unique.  It wasn’t until the year 1967 that more remains belonging to the genus Propleopus appeared.  More was discovered in the following years, but very few remains have been discovered even to this day.  With millions of fossilized mammalian bones discovered in Australia, Propleopus are “known from teeth and jaws attributable to less than 20 individuals.” 

                There are multiple reasons why an animal does not appear with a great amount of frequency in the fossil record.  Perhaps it is because the animal was small; smaller bones are much more delicate, and therefore less likely to survive the fossilization process.  (They are also a lot smaller, and therefore usually harder to find then, say the humerus of an Brachiosaurus!)  Perhaps the animal lived in an environment where fossilization is unlikely.  For example, in millions of years, when intelligent life again evolves on this planet, or we are visited by intelligent life from elsewhere in the galaxy, they would find very little or no evidence of mountainous animals, like bighorn sheep or the snow leopard.  This is because mountains are in a constant state of geologic flux.  At times they are being pushed up; but even when they are rising, they are already eroding.  Given enough time, entire mountain ranges can disappear, or almost disappear, like in the Australian Outback.  Sometimes, it is because paleontologists are simply looking in the wrong places, and there are treasure troves of these animals just waiting to be discovered elsewhere.  It could also be because the rocks where the animal was deposited simply don’t exist anymore, something that is called an unconformity in geologist’s terms.  Maybe the animal was just not very successful, and went extinct after only a short amount of time.  The fossilized animal could also represent a transitional fossil, so creatures with those characteristics would have only been around for a few thousand years.  Or, of course, it could be because the animal was a predator, and there were fewer individuals to begin with.

                Now you are probably thinking that this is quite a leap.  Just because this kangaroo didn’t appear all that often in the fossil record doesn’t necessarily mean that it was carnivorous.  And you are right, as if this was the only evidence of Propleopus being a carnivorous kangaroo, I would be laughed right out of the Neolithic Age: and they, at best, had only a very, very primitive form of language, and probably would, at best, barely understand what I was saying.  However, there is more evidence in favor of a carnivorous Propleopus.  As I am fond of saying, “the teeth tell the tale.” 

                Studies of the dentition of Propleopus show a close resemblance to small, extant insectivores or omnivores, i.e. the mountain pygmy possum and the musky rat kangaroo.  Where the teeth of Propleopus differ from the mountain pygmy possum and the musky rat kangaroo, however, the differences “could be interpreted as adaptations to meat-eating.”  To sum up, the incisors are short, stout, and appear great for stabbing, the premolars are strongly serrated, which is perfect for tearing into very tough stuff (perhaps tendon), and the molars are greatly reduced in size, as sometimes seen in the genus Wakaleo, one of the genera of marsupial lion, like Thylacoleo.  Furthermore, the molars, although reduced in size, share similar features to the largest extant marsupial carnivore today, the Tasmanian devil.  These features in the Tasmanian devil serve to keep bone splinters from penetrating the gums, and clearly would not be needed to serve that purpose in an herbivore. 

                The most revealing tale of the teeth can only be revealed by a microscope.  Studies have shown that, when you compare the microscopic wear patterns on the teeth of a herbivore and a carnivore, you can see obvious, and distinguishable, differences.  The teeth tell the tale of the diet of an animal, and help to show us what Propleopus might have eaten.  When compared with the wear patterns of closely related herbivores, like the musky rat kangaroo, and marsupial and placental carnivores, like the thylacine, Thylacoleo, and dogs, the wear patterns seen on Propleopus resembles that of the carnivores more so than that of the herbivores. 

                So was Propleopus a carnivore, or a herbivore, or both?  One hypothesis that has been put forward is that Propleopus was situated in a similar ecological niche as the modern day African baboon, eating whatever came it way, be it plants, eggs, insects, or meat.  Whatever the answer, is is doubtful that it could be answered now, and it is likely that only further research, and more discoveries, will ever hope to unravel the mystery surrounding Propleopus, the seemingly killer kangaroo.  

Acrobatic Felines: The Caracal

(Almost) everybody loves cats!  Not only the domestic kitties, but wild cats too, like the speedy cheetah, the social lion, and the elusive snow leopard, among others.  But most people don't know that there are all sorts of different cats, and thirty-six generally accepted species of cats!  Many have numerous sub-species as well, the leopard having eight or nine all by itself.

Today, I am going to introduce you to one of my absolute favorite wild cats: the caracal, which is fortunately labeled "Least Concern" by the IUCN.  The caracal is found all over Africa, pretty much except in the rainforests and the deserts, as you can see in the map below.  The caracal is also found in various non-African countries, such as Israel, Iran, Arabia, Jordan, Pakistan, and India.

I am not going to do a lot of talking (which is not normal, believe me), as words can't really do justice to what this cat can do.  So just click the link below, and be amazed.  (I actually have never watched this video with the audio on, so I don't even know what he is saying, because I think that the audio would simply detract from the video.  Enjoy!)

http://www.youtube.com/watch?v=4dCXK6KhkTw

Arthur the Aardvark

Almost everybody has heard of Arthur Read from the popular PBS show "Arthur."  What a lot of people don't realize is that Arthur is an aardvark.  And even more people don't usually even know what an aardvark is.

A fossorial (burrowing, like terrestrial or marine), nocturnal mammal from Africa, the aardvark is an insectivore, its favorite food being termites, and is labeled as "Least Concern" by the IUCN.  The aardvark, as you can see below, inhabits an incredibly large portion of Africa, including South Africa, Ethiopia, Kenya, Tanzania, Uganda, Mozambique, the Democratic Republic of the Congo (DRC), Burundi, Somalia, Angola, and many others.

The aardvark has several important adaptations for its burrowing, insectivorous life style.  Perhaps the most important are the large claws on its front limbs.  These claws enable the aardvark to not only dig out immense burrows for habitation use, but also to dig into termite mounds to extract a meal.  Interestingly, when the aardvark leaves its burrow to dig a new one, the old burrow is often taken up by the African wild dog, where the pups shelter until they are old enough to leave the protection of the burrow.

The aardvark also has thick skin, which keep the termites from biting it, allowing it to feast in relative peace.  A further adaptation to keep insects (as well as dust) out is in its nose: it can close its nose, preventing both bugs and dust from invading its breathing passages.  Finally, another very important insectivorous adaptation is the tongue of the aardvark.  The long, sticky tongue of the aardvark is usually about 12 inches long, equivalent to about one-sixth the length of the animal!  Long, sticky tongues are a fairly common adaptation for termite-eaters such as the numbat (Myrmecobius fasciatus), pangolins (Manis sp.), and the giant anteater (Myrmecophaga tridactyla) among them.

A southern tamandua (Tamandua tetradactyla) shows off its extraordinarily long tongue during an animal demonstration at one of Denver Zoo's teen career days.  Tamanduas are also insectivorous, and clearly also possess an amazing tongue.

Predators of Baby Leopards: You Might Be Surprised

One of my favorite TV shows is BBC's Big Cat Diary, which I believe I have already mentioned once or twice.  It has been called by critics as "The soap opera of the Serengeti," and has played for a number of seasons, under various other titles.  Essentially, the shows premise is a log of what two prides of lions (the Marsh and Ridge Prides) are doing, as well as my two favorites, the leopards and the cheetahs.

This is neither a leopard nor a cheetah, but a baboon skeleton.  It's probably poor planning on my part to not put a picture of what I've already talked about so far, but you're going to have to deal with it.  Or just pretend that's a cheetah, baboons and cheetahs are practically the same animal anyways.

In one episode I was recently watching, one of the co-hosts, Saba Douglas-Hamilton, said something that I thought was very interesting about leopard cubs.  She said that the top three animal threats to African leopards (besides humans, forcing the IUCN to label the African leopard as "Near Threatened,") are lions, hyenas....and baboons.  Check out the baboon skeleton (above) and mounted stuffed specimen from the American Museum of Natural History below!

I was actually completely kidding before, baboons and cheetahs are not really that closely related at all, and very few people have an excuse to confuse the two.

I knew baboons were an issue to leopards as one of the leopard stars of the earlier series, dubbed Half-Tail, was missing half her tail, hence her name.  The two hosts at the time, Jonathan Scott and Simon King, said that they thought the missing half of her tail was due to either a lion attack or, more likely, baboons.

Chilling like a villain: a leopard takes a break after staring out the window all day and stressing out about those stupid robins in that stupid birdbath.  Those robins better consider themselves lucky that there's glass between them, you mark my words.  Photo Credit: Ted and Gail Neher

I had never really thought about it before, but when I heard Saba mention it, I thought that was kind of strange.  Well, I looked up "baboon skulls" on Google Images, and I think I get it now; their canines can grow up to two inches long.  As a good comparison, the average lion typically possesses two inch long canines.  Now that is some serious dental hardware; I'm glad I'm not a baboon dentist!  (That, and I'm guessing that you don't get paid very much).

A baboon skull mounted at the American Museum of Natural History in New York City, New York.  Check out those nasty canines, they're frickin' huge!!

Baboons, like many primates (actually I believe all except for tarsiers), are omnivores, so theoretically they could use their canines to subdue and consume their prey.  However, it seems that male vs. male competition is the primary reason why baboons have such enormous canines.  Check out the "mandrill" webpage on the website for Bone Clones (for the lazy amongst you, HERE is a link), and you can see that the male has enormous teeth, while the female has a dentition that is much less impressive.  This seems to support the idea that baboons (at least the males) primarily use their teeth in interspecific intimidation, in order to frighten off other males and secure breeding rights to the females.

Works Cited:

The Cichlids of the African Rift Lakes

Three of the largest lakes in the world reside in the 3,700 mile long Rift Valleys of Africa.  These lakes, Lakes Victoria (located in the countries of Kenya, Uganda and Tanzania), Tanganyika (split between Burundi, the Democratic Republic of the Congo [DRC], Tanzania, and Zambia), and Malawi (located between Malawi, Mozambique and Tanzania), rank among the top ten largest lakes in the world; third, seventh, and ninth, respectively.  (For some reason, these rankings differ upon where you look.  Lake Victoria as the third largest lake seems pretty universal, but the ranks of Tanganyika and Malawi differ for whatever reason.  You'd think that it would be pretty universal, but I suppose not.)  Besides being such large lakes, these lakes are important for other reasons, perhaps the most important reason (for biologists, at least) being their isolation.

You see, the three great lakes are islands, of a sort.  According to Websters, the definition of an island is "a land mass smaller than a continent and surrounded by water."  The Rift Valley lakes are essentially the opposite; "a body of water smaller than an ocean and surrounded by land."  For our purposes, an island is just something that has been isolated for a time, and allowed its flora and fauna to flourish in new and interesting ways.

And flourish it did in the Rift Valley lakes.  If you were to visit these lakes, snorkel or scuba in their waters, you would most likely notice a wide variety of fish.  You would not be wrong in this assessment; however, you might be surprised to find that most of these types of fish are belonging to a group called the cichlids (SICK-lids), and that all 1,650 plus species of these cichlids descended from a common ancestor.  While the dates of when the common ancestor of the various cichlids came to be trapped in their respective lakes, it has been estimated that the cichlids of Lake Malawi all evolved from a common ancestor trapped 700,000 years ago, and those of Lake Victoria around 12,000 years ago.  Trapped in these growing lakes while they were being formed, this small group of fish quickly came to dominate their new home, exploding in biodiversity to adapt to the wide variety of niches left open to them.

Tenuous can this biodiversity be, as recent logger-based erosion has shown.  Logging nearby to one of the lakes resulted in rapid erosion.  This erosion caused a great deal of silt to build up in one of the lakes.  This, of course, caused the water to become quite murky; think about your average beach, and how murky the water often is near the shore.  Many of the cichlids that lived in this area relied upon visual identification to recognize members of the same species for mating purposes.  With the cloudy, muddled water, this became quite difficult.  As a result, many fish from closely related species ended up mating with each other and, in the case of many of the couplings, resulted in viable offspring.  These viable offspring in turn bred with other species, lowering, at least temporarily, the biodiversity of the cichlids in this particular corner of the lake.

Blantyre on Dwellable

Cloning the Cheetah: Why Bother?

In an attempt to discover why the cheetah has such a low fertility rate, a team of scientists, including David Wildt and Stephen O'Brien, decided to take a look at blood samples from a number of cheetahs, labeled "Vulnerable" by the IUCN.  What they found was startling, and very worrying; the cheetahs appeared to be dangerously, perilously inbred; they were all practically clones of each other. 

Wildt and O'Brien decided to confirm this hypothesis by taking skin samples from a number of cheetahs, and attempting to graft them onto a number of other cheetahs.  In a healthy population of animals, the skin grafts would be immediately rejected.  This is because the body of the animal who received the skin graft would recognize the skin to be from another individual, a foreign body, and attack it, just as it would attack any foreign body (i.e., germs or bacteria.)  Even in humans, skin grafts are often rejected, even ones from close relatives.

Normally a very majestic looking animal, this particular cheetah seems to have been caught at a bad time.  Photo Credit: Ted and Gail Neher

So when every single one of the cheetah skin grafts were accepted by the other animals, this did not bode well for the cheetah.  This meant the genetic diversity of the cheetah was incredibly, shockingly low.  But why is genetic diversity so important?  Well, without genetic diversity, the DNA of the individuals comprising a given population are very similar.  These individuals essentially become clones of each other, with many similar attributes, most important among them their immune systems.  In a healthy population of, say, cheetahs, say that fifty percent of them are immune to a certain disease, most of them evolving from a common ancestor.  The other fifty percent of the population has absolutely no protection against said disease, and the illness ravages their population.  An unfortunate (and oversimplified) event, to be sure, but fifty percent of the individuals remain to rebuild the population to what it once was.  With the low genetic diversity seen in the cheetah, if a similar disease in the hypothetical above sweeps through Africa, it is quite likely that a much lower percent than fifty would survive.  It is also possible that this disease would so ravage the global population of cheetahs that they would simply be unable to recover from this catastrophic event.

A cheetah scratching a log at the Denver Zoo.  The cheetahs incredibly slender build can help distinguish it from other cats. 

So why is the cheetah so catastrophically inbred?  Most of the time, low genetic diversity is due to a given species having passed through a "bottleneck."  20,000 years ago, cheetahs spanned the entire globe; ranging all over Europe, Asia and Africa, two species of cheetah, or "proto-cheetahs" if you will, even roamed North America (Miracinonyx inexpectatus and M. trumani.)  When the most recent Ice Age drew to a close around 10,000 years ago, the dramatic climatic changes (and likely human influences, as well) resulted in the extinction of much of the world's mammalian megafauna. Researchers think that this mass-extinction managed to knock the cheetah's numbers down to a very small population, likely comprising a mere handful of individuals.  (In fact, I remember reading once that at one time, some people thought that a single pregnant female mother was able to survive, but I don't think that this idea is all that highly regarded anymore).  While the cheetahs were obviously able to build their population numbers and density by a significant amount than that seen 10,000 years ago, this bottleneck came with a price; genetic diversity was, and is, miniscule.

Works Cited:

The Biggest Carnivorous Dinosaur Part 3: Spinosaurus, The World's Largest Penguin

Spinosaurus quickly smashed its way to the top (literally!) following the success of Jurassic Park III.  At up to 56 feet (17 meters) in length, Spinosaurus (found in Egypt and Morocco) is unquestionably the longest carnivorous dinosaur that has ever been discovered, and by a significant margin, too.  But how could Spinosaurus be so successful when another carnivorous monstrosity, Carcharodontosaurus, lived in such close proximity?  The answer lies in what it ate; in fact, Spinosaurus appears not to have been as carnivorous as we once thought, and seems to in fact have been more piscivorous.  Essentially, it is thought that Spinosaurus might have survived on a diet consisting a great deal upon fish.

There is a great wealth of information that indicates the staple diet of Spinosaurus was fish.  Here we will take a more in-depth look at this evidence.

A picture of Spinosaurus drawn by the talented young artist Sam Lippincott.

1.  POSITION OF THE NOSTRILS:  Spinosaurus, unlike most other theropod (meat-eating) dinosaurs had nostrils situated very high up on its skull.  By contrast, most other theropods, like Tyrannosaurus, had nostrils very close to the front of the skull.  The nostril placement in Spinosaurus would have allowed it to stick its nose into the water quite deep, enabling it to hunt fish more effectively.

2.  SENSORY ORGANS ON THE TIP OF THE SNOUT:  Along with the high placement of the nostrils, Spinosaurus also had a number of small sensory organs at the front of the snout, revealed by CT scans.  These greatly resemble those of the crocodile, who uses them to sense where prey is by "seeing" tiny movements in the water.  Thus, a crocodile can attack its prey without ever seeing them with their eyes.  Spinosaurus appears to have been able to do much the same thing, making its hunting method of choice quite obviously effective, given its immense size.

3.  ISOTOPIC EVIDENCE:  A study of the isotopes in the skull of a Spinosaurus specimen revealed something quite interesting.  Spinosaurus shares a great deal of isotopic overlap with crocodiles, fairly aquatic animals.  By contrast, other carnivorous dinosaurs like Tyrannosaurus have very different isotopic readings, indicating a terrestrial lifestyle.  Given the great deal of overlap possessed by Spinosaurus and crocodiles, it appears that Spinosaurus spent much of its life like a crocodile; semi-submerged in rivers and streams.

4.  THE TEETH TELL THE TALE:  Spinosaurus, unlike most other carnivorous dinosaurs like Tyrannosaurus, Allosaurus, or the famous Velociraptor, possess conical, round teeth.  These other carnivores possess thin, blade-like teeth, made for slicing, crushing or tearing into other animals.  Spinosaurus has teeth much like a crocodile; round and conical.  These teeth are made for gripping and making sure that an animal does not escape. 

5.  THE TEETH TELL THE TALE....AGAIN:  Yet again, we come to the issue of teeth, and this is one of the most damning pieces of evidence of all.  During the time that Spinosaurus lived in North Africa, another inhabitant of these streams and rivers was a saw-toothed fish called Onchopristis.  Two fossils involving Onchopristis have been discovered in conjunction with the remains of Spinosaurus.  One was the skull of a Spinosaurus; imbedded in one of the tooth sockets was a vertebrae from an Onchopristis.  The other discovery was the barb of an Onchopristis embedded in the jaw of the Spinosaurus.

6.  PLUS:  We only ever seem to find Spinosaurus in shallow aquatic environments, where fishy prey would be abundant.

All in all, it seems like an inevitable conclusion to draw that Spinosaurus was, in fact, a piscivore, at least much of the time.  A fascinating example of the crazy turns evolution can take.

The Biggest Carnivorous Dinosaur Part 2: Carcharodontosaurus Vs. Spinosaurus

As I promised yesterday, today we are going to take a closer look at Carcharodontosaurus (kar-kar-o-DON-to-SAUR-us).  Carcharodontosaurus was a relative of Colorado's own Allosaurus.  However, Carcharodontosaurus was four times larger, and found in Egypt, Morocco, Algeria, Libya, and Niger.  At around 46 feet long, Carcharodontosaurus was similar in size to yesterday's Giganotosaurus (pronounced jig-a-NOTE-o-saur-us), and longer than Tyrannosaurus, though Tyrannosaurus was undoubtedly much bulkier.  Regardless, Carcharodontosaurus was a monster-sized killer, and almost certainly had a monster-sized appetite to match.  It is almost a certainty that such an animal would have a fairly large territory, and would have needed to eat a great deal to maintain its fast metabolism, similar to your average teenage dude.

Clearly, such a large predator had little competition from other carnivorous dinosaurs.  Or did it?  As a matter of fact, 95 MYA, North Africa was home to not one, but two monster-sized killers, Carcharodontosaurus, and the even longer, 50 foot (15 meter) Spinosaurus.  (Some not so conservative estimates even place the maximum size for Spinosaurus as 60 feet (18 meters) in length, but this does seem extreme.)

Now, in the modern day, predators can inhabit the same area.  Take the plains of Africa, for example; in many places, lions, leopards, cheetahs, wild dogs and hyenas all inhabit the same area.  There is a clear hierarchy amongst the animals, and each seems to get enough to eat.  However, this is partly because each animal exploits a slightly different set of resources, so contact amongst them is less frequent than if all five of the large carnivores all hunted the same animal, say, the Thomson's Gazelle.  This is a phenomenon known as resource partitioning, and it occurs all over the place in nature, arguably one of the most important factors involving ecology and evolution. Scientists believe that a similar sort of partitioning took place between the two mega-carnivores of Mid-Cretaceous North Africa, with Carcharodontosaurus being a terrestrial carnivore, while Spinosaurus took to the water.  We will conclude "The Biggest Carnivorous Dinosaur" trilogy tomorrow with a look at the environment Spinosaurus was able to so successfully exploit.

A fantastic visual representation of resource partitioning amongst large herbivorous mammals in Africa.  The giraffe, the zebra, and the wildebeest will all inhabit the same area and eat plants, but the types of plants can differ.  Photo Credit: Ted and Gail Neher

The Biggest Carnivorous Dinosaur Part 1: Move Over, T-Rex (Kind Of)

Tyrannosaurus rex, the "Tyrant Lizard King," has long been a dinosaurian favorite the world over.  He is quite the interesting animal, and simply massive; the publicity received by him and the giant-sized Velociraptor in Jurassic Park helped a bit, I'm sure!  However, T-rex is no longer thought to be the largest carnivorous dinosaur.  Well, yes he is.  But he isn't.

A picture of the Tyrannosaurus rex specimen Stan at the Morrison Natural History Museum.

Imagine someone who has never heard of the giraffe and elephant asks you which one is biggest.  You might say the elephant, because the elephant is much heavier and has more bulk.  But what if they mean which animal is taller?  Somewhat of a dilemma.  So using words like "biggest" (as I have done here) is not the best way to go.  So Tyrannosaurus still seems to be the heavyweight champion, there are other dinosaurs that, while more slender, were probably longer.  Kind of confusing, I know.

The fact that T-rex has some serious competition has put barely a dent into his popularity, and some of the other larger carnivores are receiving a lot of attention, too. The longest of these carnivores, which we will learn about on Wednesday, was possibly around 20% larger than Tyrannosaurus Rex!  Today, we are going to look at another enormous killer, of South American origin; the massive, the monstrous, Giganotosaurus.

A Giganotosaurus on display at Fernbank Museum, in Atlanta, Georgia

Giganotosaurus is an estimated 46 feet long, comparable in length to the average Tyrannosaurus!  We do have some specimens of Tyrannosaurus that are around the same size as Giganotosaurus, but either way: Giganotosaurus was a massive animal! Of course we don't actually know for sure what the maximum size for any dinosaur is as, unlike for most living animals, we generally have a relatively small sample set, but we can make close estimates based on the finds we have.  And these estimates indicate that Giganotosaurus grew to simply massive proportions.  One of the largest terrestrial animals that we know of is Argentinosaurus (who, like Giganotosaurus, was also found in Argentina), a sauropod dinosaur that lived at the same time as Giganotosaurus.  For Giganotosaurus to prey on even the juveniles of such a large herbivore, it would similarly need to grow to massive proportions.

Giganotosaurus vs. Argentinosaurus at Fernbank Museum, in Atlanta, Georgia

Giganotosaurus vs. Argentinosaurus at Fernbank Museum, in Atlanta, Georgia

This pattern repeats itself all over the world, the pattern of gigantism evolving in sauropods, along with the subsequent evolution of gigantism in the theropods (meat-eating dinosaurs), is a pattern repeated throughout the world, and throughout the Jurassic and Cretaceous Periods of the Mesozoic Era, the two periods in time when the rule of the dinosaurs was absolute.  Here are some more of the predator-prey, giant-sized carnivore/giant-sized herbivore relationships seen throughout the Mesozoic.  The first animal named will be the predator, and the second will be the sauropod.

Asia, 160 MYA: Sinraptor, Mamenchisaurus
Europe, 125 MYA: Neovenator, Ornithopsis
North America, 150 MYA: Allosaurus, Diplodocus
North Africa, 95 MYA: Carcharodontosaurus, Paralititan

In tomorrows post, we will look at the last relationship, and focus on another larger (or longer) than life carnivore, Carcharodontosaurus.

Another Living Fossil: The Coelacanth

400 millions years ago (MYA), during the Devonian Period, life had already gained a foothold on land.  However, in the seas, unless you were at the top of the food chain, there were a lot of predators to contend with.  If you were a fish in the middle of the food chain during the Devonian, you not only had to deal with ancestors of the modern day shark, but a now-extinct group of armor-plated fish, called the Placoderms.  Some of these Placoderms, like Dunkleosteus, grew to simply enormous proportions, around 30 feet in length!  One type of fish that lived during the Devonian and was most likely preyed upon by the sharks and the Placoderms was a fish known as the Coelacanth.

The Coelacanth (SEE-lah-canth) was a relatively unassuming fish, its closest living relative being the lobe-finned fish.  Fossils of the Coelacanth have been discovered ranging from 400 MYA to around 65 MYA, coinciding with the death of the dinosaurs.  In 1938, however, when one was hauled in on a fishing net off the coast of South Africa, the temporal range of this animal was extended by 65 million years!  Today, by studying the living Coelacanth, scientists have found that the fish gives birth to live young, unlike other fish.  Further discoveries both in Africa (off the coasts of Mozambique, Madagascar, Kenya and Tanzania) as well as Asia, around Sulawesi, Indonesia, of living Coelacanth specimens have further widened the current geographical range of the Coelacanth.

A specimen of the Cretaceous coelacanth Coccoderma nudum from Germany.  On display at the Mace Brown Museum of Natural History on the campus of the College of Charleston in South Carolina.

Unfortunately for this living fossil, it is labeled "Critically Endangered" by the IUCN, much like yesterday's living fossil, the mountain pygmy possum.  Just like the mountain pygmy possum, conservationist groups are working towards it's protection, trying to keep fisherman from fishing in the Coelacanth's habitat.  Hopefully, humans won't be the final nail in the coffin, so to speak, for this 400 million year old fish.