What Is It? The Weekly Challenge #3 Answer

Today's animal was easier for many of you, and we had a number of good guesses!  We had a few close guesses (like the American Kestrel, another North American bird of prey, but we had one totally right answer.  This weeks winner is Julie N., who guessed the Peregrine Falcon!

Peregrine Falcon

 The Peregrine Falcon is one of my favorite birds, mainly because of how it hunts.  It dives at medium-sized birds from up to 3,000 feet in the air, and often dives towards the birds with the sun at its back; that way, its prey has a difficult time of seeing them through the sun's glare.  In its dive, speeds of 175 - 200 mph have been recorded, placing it at the terminal velocity able to be achieved by the bird.  Some people have reported that the peregrine can exceed terminal velocity but, despite being taken in by this theory for a time, I believe that this not, in fact, true.  (I am not that into the math or physics, but I believe it might even be impossible, but I'm sure some of you know that better than me!)  Click on the link below to learn a little more, and to see the bird in action!

http://www.youtube.com/watch?v=cKqt05iR9WI&feature=player_embedded#!

Although their population numbers suffered tremendous, pesticide-induced blows during the 20th century, they have made quite a comeback throughout the United States.  However, it was a close call.  Use of pesticides like DDT (commonly known as DEET, used to be common in mosquito repellent before its negative impacts on the environment became fully known) caused the Peregrine Falcon's eggshells to become weak, and they were easily broken.  The result of this was very few baby falcons surviving to breed themselves.  In fact, at one point it got so bad that the Peregrine Falcon was listed as "Endangered" by the IUCN in the 1950's through the 1970's.  It became extirpated, or locally extinct, in both Belgium and the eastern United States.  However, now it is labeled as "Least Concern;" an amazing comeback, for an amazing bird.

This picture of the Peregrine Falcon was taken by me, last week at the Reptile Day at Dinosaur Ridge, near Golden.  My friend Masaki Kleinkopf and I went and were able to see a few pretty cool things, the Peregrine Falcon being just one of them.  I highly recommend going to check out the Ridge, as well as the museum they have there, it is really quire interesting!

Don't forget to check in later in the day for this week's challenge!

Animal Spotlight: The Bobcat

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The bobcat is one of three main felines that lives in North America, the others being the Canadian lynx and the mountain lion.  (Although other cats, like the jaguar, jaguarundi and ocelot, do occasionally make it up to Texas and Mexico, generally they just live in Central and South America).  Labeled "Least Concern" by the IUCN, the bobcat averages around three feet in length, and is named such for the short, "bobbed" tail.

A bobcat at The Living Desert in Palm Desert, California.  Note the short, stubby tail.

The bobcat is quite adaptable; it inhabits almost every single environment that the Continental United States has to offer, as well as most of Mexico.  There are thirteen recognized sub-species of bobcat.  Furthermore, despite its size, can be strong enough to take down small deer.  Here is a link to a video about a bobcat that I found to be quite interesting.

http://www.youtube.com/watch?v=S5BfNtim148

When we went camping last week, twice did we see paw prints that looked too small to be mountain lion prints, and were most likely bobcat prints.  I was quite excited; unfortunately (but not surprisingly) we didn't see any of the cats themselves.  Here is one picture from each of the times we saw the tracks. 

East Palm Desert on Dwellable

The Fauna of South Carolina: Reptiles and Amphibians

First off, don't forget to look below to see the answer to last weeks mystery animal, and to see a couple of pictures of this weeks!

Recently, my family visited some good friends of ours in South Carolina for a few weeks.  Not only did we have a lot of fun visiting them, we saw a lot of cool plants and animals there that we simply don't have up north!  For some of you, many of these animals and plants will be routine and boring, but hopefully there will be something in here that you will find interesting!  I think I am going to split this post up into at least a few different segments, with tomorrows post devoted entirely to the Black Skimmer, a very interesting bird that I had the good fortune to see hunt!  So today I am going to talk about some of the interesting reptiles and amphibians we saw down there, and over the next few weeks we can take a look at some of the birds, fossils and other things we saw down there!

Due to the increased heat and humidity, coupled with less of a swing between the seasons (i.e. it rarely snows and drops below freezing), the south is an excellent place to see all sorts of reptiles and amphibians.  We saw a number of turtles and a frog/toad or two when we were in the south, but what interested me more were the lizards.

A Carolina anole (Anolis carolinensis).  Despite its name, the Carolina anole is found in both South and North Carolina, as well as Florida, Georgia, Louisiana, Texas, Alabama and Mississippi.

A type of skink, but I have yet to ascertain its species, although I am almost certain its genus is that of Plestiodon

And then, of course, there's the gators.  The American Alligator lives in the same states as the Carolina anole, as well as Virginia, Arkansas and Oklahoma.  While we did see a few in the wild, all of these shots (except for that of the gator footprint) were taken at a place called Brookgreen Gardens, or at a restaurant called the Crab Shack.

This big gator we saw at Brookgreen Gardens

This is a picture of a gator footprint that I took.  You can see three of the toes very well, making it look a lot like a theropod dinosaur track, but you can see the other two toes as little holes in the ground.

This picture, and all the rest, were taken at an awesome (both food- and entertainment-wise) restaurant on Tybee Island in Georgia called The Crab Shack.

 

 

 

 

 

 This post is part of "The Fauna of South Carolina" series.  For the rest of the posts in this series, click HERE.

Sea Pines 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 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.