Sunday, March 31, 2013

Hiatus (sad face)

I was recently accepted to an internship working on giant kangaroo rats in the Carrizo Plain. I have only just arrived at the site and can't tell you how excited I am to begin work.

However, like all good things, it comes with a cost. There is little internet access here, and probably less free time. I do not believe I can feasibly do a post everyweek, and so, with a heavy heart, I am putting The Everyday Animal on a hiatus until further notice.

However, I will try and keep everyone up to date on my field work through my other blog: For Science Sake. I encourage you all to visit it to see what ecology field work is like.

I greatly enjoy these posts, and sincerly hope tto continue them in the future. This field work will be 2-4 months, but once I am back in the modern world I hope to continue giving out great animal info.

Thank you so much to everyone who has been a supporter and reader of this blog! This is not the end, I promise, just a break.

Saturday, March 30, 2013

The Darker Side of Cute: Domestic Rabbits

Baby Bunny!!
Photo source: The Pix Host
Whether or not you are spending this weekend searching for colorful eggs hidden by an enormous bunny (what?) there is no denying that rabbits have become one of the largest symbols of spring. And why not? They are cute, fluffy, domesticated, and during spring they reproduce like... well, like rabbits.

The rabbits that you are probably picturing now have been domesticated since the days of cavemen, but not always for their companionship.

The European Rabbit (Oryctolagus cuniculus) has become the variety of domestic breeds that we know today. White with brown splashes, or a granitic gray with big black eyes, or all black with just a tip of white on the nose; bunnies are known for being adorable. But when they were first domesticated, it wasn't for ooos and awws. It was for their meat.

Rabbits were first kept by people in large numbers during the Roman Empire. The Romans kept rabbits as a source of food, helping to transport the rabbits throughout Europe as the empire grew [1].

But the actual domestication of rabbits took place in France behind monastery walls. French monks lived in seclusion but needed a source of meat that could be easily kept within the monastery. Better yet, a food that they could eat during lent.

In 600 A.D. Pope Gregory I declared unborn or newly born rabbits, laurices, to be officially classified as "fish." Although the reasoning behind the declaration was probably more about giving the monks a break than actual taxonomic logic, it did allow the holy-men to consume, keep, and breed the rabbits, since fish was allowed during the days of lent. While never fish, through breeding and selecting for desirable traits, the monks did become officially domesticate the European rabbit [2].

By the 16th century rabbits had spread throughout Europe. Distinct breeds were developed and described, and they were becoming more popular for their fur and adorable attributes, rather than just their meat [3].

From the European continent, rabbits began traveling the world. Often sailors would release colonies of them onto islands to ensure that there would be a large food supply available for future voyages. Today the European Rabbit can be found throughout the world except for Asia and Antarctica.

Of course many islands do not have native rabbits, hares, or even mammals for that matter. The introduction of this glutinous, greedy, and lusting little bunny has destroyed ecosystems world-wide. One of the most dramatic examples is the invasion of rabbits into Australia.

In 1859 Thomas Austin released 24 European Rabbits onto Australia near Victoria [4]. Today there may be 200-300 million rabbits throughout the small continent [5]. On a diet of plenty and with no natural predators, the they multiplied. 

Rabbits are natural diggers. They make their burrows underground and will move a considerable amount of dirt to do so. With a small population, digging might not be a problem, but with hundreds of millions of rabbits digging up Australia they have caused major erosion and created an ecological nightmare. It is estimated that 1/8 of all native Australian mammals are in trouble because of the rabbit invasion [5].

By the begging of the 20th century Australia's ecology and agriculture were in trouble. Shooting and trapping were not enough to curb the rabbit population, so to stop their spread the government tried something a bit more grandiose. In 1907, the government finished building the world's longest continuous fence. At over 1100 miles, the fence separates the entire western side of the continent. A second fence was also built, stretching just over 700 miles farther west of the original. But fences break, and rabbits dig, and despite the enormity of the project it was eventually deemed a failure. The rabbits continued their invasion.

Finally, in the 1950s a more drastic approach was attempted. The myxoma virus, endemic to South America, is carried by mosquitoes from host to host and is lethal to almost 100 % of those that catch it. But, with a catch, it only affects rabbits. So in 1950 mosquitoes carrying the myxoma virus were released.

The impact was huge. 90-99% of the rabbits throughout Australia were wiped away in a sea of disease. But 1-10% remained, and they remained because most had a genetic immunity to the disease. So, spreading their immunity throughout the new population, the rabbits procreated and their numbers rebounded with force. Today myxoma is only 40% effective, not enough to keep the numbers in check. Since the failure of the myxoma virus, other diseases have been tried with similar failures [6]. The rabbits continue to invade Australia, having thwarted everything people have thrown at them. It is an ecological war that the rabbits seem to have won.

So a reminder as you are biting off the ear on a chocolate bunny this holiday (or after, when they are so much cheaper), munching on rabbits has a long tradition, and gave us the furry friends we have today. Just don't take your chocolate bunny to Australia.

Sunday, March 24, 2013

Week off. Sorry.

I am taking a week for travel. But don't worry, I've got some awesome science info for you in the form of one of my favorite nature documentaries.

I highly encourage you all to watch this PBS documentary on sexual selection. Enjoy!


I male peacock's version of dinner and drinks
source: Wikipedia

Sunday, March 17, 2013

Our Dependent Guest: The Housefly

The Common Housefly
Photo from How Stuff Works
Spring is here! And with it comes cute baby bunnies and chicks, a wide array of beautiful flowers, and of course, houseflies.

They are not the most appealing animals to emerge this time of year, but they are just about everywhere. A single female housefly can lay up to 900 eggs in her lifetime [1]. And where to lay those eggs but in a delicious, moist pile of manure, giving her baby larva something to snack on when they hatch. Sound disgusting? Fascinating? You don't know the half of it yet.

Houseflies probably first evolved in the Africa, later hitching a ride with us to all the corners of the world [2]. In fact, houseflies are surprisingly dependent on us. They eat our food, use our animals' waste as a nursery and use our structures to take shelter so that they can make it through cold winters, ready to emerge when the weather warms up [3]. And emerge they do. Undoubtedly you will begin to see them land on your wall, ceilings, and food.

But the housefly has one big disadvantage when it comes to eating solid food: they have nothing to chew with. In fact it is physically impossible for a housefly to eat solid food. But they are able to get around this problem by liquefying our otherwise solid meals. With a straw-like mouth piece called a proboscis the housefly will drink up any liquid food that it can. When the food is to tough though, it will use tiny hairs at the end of its proboscis to scrape off some food particles. Then, the fly will vomit. It vomits digestive juices onto the food, dissolving them into a liquid and slurping it all back up [1]. Gross? Maybe, but it is exactly what we do, only we do it inside our bodies, chewing food into particles and dissolving them in our stomachs. Really we and the housefly have a very similar process, but our's takes place inside our bodies, and their's, out.

Sorry Mr. Larson, but you got this one wrong.
picture from pbase.com
But while we might use a new straw for every Slurpee, flies do not have that convenience when it comes to their proboscis. Inevitably some old food gets stuck in the tube, only to be vomited back out again, mixing with what was going to be your delicious dinner. Not all of it gets slurped back up again, leaving you with a glop of partially digested food and fly vomit. And thus, flies have gained a not-undeserved reputation as dirty, disease-spreading pests.

They are almost the perfect animal for spreading disease. They lay eggs in wet organic matter like dung, or compost or trash, picking up potentially deadly diseases like typhoid fever, salmonella, dysentery, even anthrax [4]. They then land on your food, or you, delivering diseases to your front door.

But simply carrying such diseases wouldn't be so bad if they weren't so hard to kill. After all we can't all be the Karate Kid. But what makes swatting a fly so difficult?

Flies are extremely well adapted to sensing motion of any kind, and are great at aerial maneuvers. The eyes of the housefly are extremely complex. If you have ever seen a picture of a "fly's eye view" with a thousand of the same picture seen in every widow, forget that. Seeing the same image over and over and over and over again makes very little evolutionary sense. In reality, each lens on a fly's eye acts like a one of ours. You can think of a fly having not two eyes, but up to 12,000 that are arranged in two semi-circle bundles [1].

A (probably) more accurate picture of a fly's view
Photo from flickr
This creates an image for the fly that severely lacks resolution, but is exceptional at sensing movement.

But the housefly doesn't stop with the eyes. It's body is covered with tiny hairs, known as tarsi, that are extremely sensitive to air movement. They can feel the air being pushed by that flyswatter coming at them, and they can get out of the way fast [1].

And once in the air they have a myriad of tricks they can perform. Tight turns, zigzags and loop-de-loops all help a fly get out of the way in a fast and unpredictable manner. These tricks are due to two extra wings that the fly has just below it's large main ones, and the ability to process information at astounding speeds. While its main wings beat furiously (up to 20,000 times per minute) [5]  two small wings, called haltere, are stabilizing the fly in mid air and the fly is taking in, processing information, and reacting to it in a few hundred milliseconds. They react in literally the blink of an eye [6].

And they need those reaction times. Birds, lizards, spiders, insects and swatters are a constant threat. So before you pick up that bug spray, just remember that these amazing animals live in world that is dangerous enough as it is. Just, maybe don't let them land on your food.

Monday, March 11, 2013

More Than A Bird Brain: The Crow

The American Crow
Photo from All About Birds
The crow doesn't seem all that impressive on the surface. Sporting an all-black coloration, the American Crow stands at only 44 cm (17.5 in) [1] and even has a dry, raspy caw that is neither pretty nor seems to draw much attention.

In pop-culture they are portrayed as either trash-birds or harbingers of death and disaster. Just think of the last zombie movie you saw.

But under their glossy black coat, crows are not only impressive, but mystifying. They are some of the smartest birds on the planet (one species may be THE smartest bird) and they are social animals that work and even raise families together. In other words, we share some traits in common.

Crows form closely-knit family groups. They are monogamous, faithful to their spouse, and even the crow-children stay close to the home. Many will forgo an opportunity to try to start a family of their own in order to help raise their brothers or sisters [2]. And their social personalities are not limited to their household. Crows stick together in large groups to forage for food. These groups can be big. Very big. A single flock of crows, known as a murder (pop-culture strikes again) can include well over a million individual birds, sometimes up to two million [3].

These impressive gatherings can usually be found around human settlements. American Crows are notorious for their ability to thrive in the conditions we create. Like humans, crows enjoy open landscapes with a few trees and perches, making our parks, cities and towns perfect ideal. Our commonalities with crows may go all the way back to a time when both species were foragers.

Crows played an important role in early human culture throughout the world. Thriving on carrion, crows could be found feeding on the recently deceased, linking them in many people's mind to the afterlife and religion. But crows feeding habits connected them to us in more ways than one. Humans are social, and group hunters, and crows undoubtedly grew close to us, knowing we could provide them with delicious scraps [4].

That kind of adaptability is what crows are famous for. Crows are incredibly smart, and American Crows is particularly talented in at least one respect: face recognition.

In a 2006 study, researchers the University of Washington captured crows, tagging them for later identification, all while wearing a mask. Recording the response of those crows later, they found that they reacted very little to researchers without the mask, but became aggressive when the researchers had the mask on, sometimes even diving at the researchers. The same response even came when different people wore the mask, indicating that it was indeed the face that they recognized [5]. What they also found was that crows that weren't originally caught responded in the same way. Crows could spread that knowledge through their avian society telling each other which humans were dangerous [4].

But they can indicate more than just warnings to each other. After walnut trees were planted in Japan, Japanese Crows began to take the hard-to-crack shells and place them behind the tires of parked cars or in the street. The cars would drive over them, Crrack, and crows would pick up their nutty profit.

This technique did not pop-up randomly either. It began in one small area of the city, with maybe one or two crows, and was gradually recorded father and farther out. a wave of knowledge from crow-to-crow spreading throughout Tokyo [4].

But arguably the most famous of all crow species is not from America, or Japan, but New Caledonia, a small tropical island off the coast of eastern Australia. The New Caledonian Crow might not be an everyday animal, but I would be remiss if  I didn't talk about them in a crow post.

An amazing feat by a New Caledonian Crow.
Photo from BBC
The New Caledonian Crow is possibly the smartest bird in the world, and maybe one of the smartest animals period. To get at tasty insects, the bird picked up a useful skill: it has learned to use tools. More than that, they have learned to create tools.

The crows can pick up sticks and sharpen them or bend them to solve the problem as they see fit. In a famous behavioral study from Oxford, New Caledonian Crows had to lift up a weight with a handle from the bottom of a long tube, and were given only long, thin, straight wires to do it with. The crows, upon discovering that straight wires could not help them, bent the wire into a hook, and hooked and lifted the weight [6]. Such cognitive abilities are unique among birds and are much greater than many primates, and even better than some human children.

More recent studies indicate that the New Caledonian Crows may even have knowledge or ideas of things that they cannot see, much as we do about microbes, atoms, and even gods [7].

Where ever they are located, crows around the world are social, highly intelligent and perhaps deserving of more respect than people give them. But they are still hunted in large numbers, and although some species such as the American Crow is doing well, others like the Northwest Crow and the Hawaiian Crow may have already gone extinct.

So the next time you see a crow in the street, or in the park, or nibbling on some trash, don't be so quick to dismiss it. Stop, give a thought to it's complexity, its resourcefulness, and its adaptability, and then be on your way.


For more on crows, crow studies, and the amazing-ness that is crows, here are some great videos:

Note: because I have linked my sources in the post itself I will no longer be posting them separately afterwords as well. Similarly because I have posted links to the pictures used I will no longer be posting that separately. If you have thoughts on this or you would like to see these sources added back to the bottom of every post, please leave a comment below.



Saturday, March 2, 2013

What's the Difference: Crows and Ravens

A crow and a raven, respectively.
photo by Gerrett Lau
You see a black bird flying overhead in the middle of a crowded street. Is it a raven? A crow? How can you tell? Should you care? Absolutely. Crows and ravens may seem like ordinary birds but they are anything but. To those in the know, they are clever, mischievousness, successful and frighteningly intelligent animals.

But your confusion is understandable, after all they are both sleek black birds that you see everywhere and they are very closely related; both belong to the genus Corvus. Many species of Corvus exist throughout the U.S. but on the west coast you are probably most familiar with: The American Crow (Corvus brachyrhynchos) and the common raven (Corvus corax[1][2].

The American Crow is a highly sociable bird and can form enormous flocks (lovingly known as "murders") that can include over a million individuals. The American Crow is significantly smaller than the common raven but, not to be outdone, it uses its larger numbers for success in both breeding and hunting.

Crows are monogamous but often form large family groups where older offspring help parents take care of the new chicks; sometimes staying with the parents for many years. 15 birds to a nest is not uncommon [3][4]. Each individual helps provide food and care for the family, and they work as a team to acquire food. Teams of cunning crows have been known to distract predators while another crow sneaks in from behind to steal the predator's hard-earned meal [5]. This is all to say that if the black bird you see is one just one in a flock, you can be fairly certain it is a crow.

Ravens on the other-hand live a more solitary life. They can form mating pairs, but it is rare to see more than two together [5]. But like crows the ravens can work together to get prey and are extremely clever at finding food, but their size is less of a factor. Common ravens are the largest of all American corvids, and its one of the primary ways they can be distinguished. Ravens also prefer woodlands, open-landscapes, and mountainous areas to cities and towns. Ravens are not uncommon in urban areas, but they do not seem to have the affinity for human settlement that crows do [6].

But like everything in nature, exceptions are all to common. Common ravens can occasionally be seen in large flocks in the cities, and crows can be seen all alone in the forest. When you are unsure, beaks and tails are tell-tail signs (see what I did there?). Ravens sport a wedge-shaped tail and a longer, heftier beak. They also sport distinctive neck plumage when they call. This is opposed to the squarer tail and smaller, rounder beak of the American Crow [7][8]. Still unsure? Look for it's flight pattern. If it is performing acrobatic tricks, its probably a raven.

While crows flap almost continuously in flight, ravens are known to glide for long periods and take this time to show off mid-air stunts. famous for their aerial acrobatics, a raven was even recorded flying upside down for more than half a mile. Quick dives up and down, somersaults, and even dropping and catching objects in mid-flight are common sights if you pay attention when ravens fly by [5].

Their calls are also distinctive, and fitting to their body-type. The smaller American Crow's calls are higher pitched, and you can often hear many of them together. Their calls are probably the most familiar to you, the traditional caw-caw [9]. Common ravens have a deeper, harsher voice, and often can be heard alone [10]. But before you identify them on sound alone, you should know that both crows and ravens produce a variety of sounds and are notorious imitators; even mimicking human speech.

Up until now I have been hesitant about writing a crow or raven post. Not because their isn't enough to say about them, but because there is an intimidating amount. Intelligence on par or over some primates, these birds are extraordinary, and now that you know the difference you can look forward much more extensive posts on them coming soon. In the mean time let me know what animals you want know the difference between and keep up with animal facts and science news on my Twitter: @everydayanimal.

More information on the differences between crows and ravens:
http://birdnote.org/show/ravens-and-crows-who-who
http://www.youtube.com/watch?v=guBwMUAWAJI
http://www.allaboutbirds.org/page.aspx?pid=2501



Sources:
[1] http://www.allaboutbirds.org/guide/American_Crow/lifehistory
[2] http://www.allaboutbirds.org/guide/common_raven/id
[3] http://www.birdweb.org/birdweb/bird/american_crow
[4] http://www.news.cornell.edu/chronicle/97/4.10.97/crow.html
[5] http://www.allaboutbirds.org/guide/common_raven/lifehistory#at_nesting
[6] http://www.birdweb.org/birdweb/bird/common_raven
[7] http://animals.nationalgeographic.com/animals/birding/common-raven/
[8] http://animals.nationalgeographic.com/animals/birding/american-crow/
[9] http://www.allaboutbirds.org/guide/American_Crow/sounds
[10] http://www.allaboutbirds.org/guide/common_raven/sounds

Photo by Garrett Lau from:
http://birdnote.org/show/ravens-and-crows-who-who