Dog Growls and Size Determination

Dog Growls and Size Determination

In the animal world, a receiver can deduce a lot about the sender including the fitness of the sender. For example, in class we learned about how trill rate and frequency bandwidth of a New World Sparrow is correlated with the fitness of the bird. Something similar occurs in dogs, where dogs can deduce the size of another dog by their growls and respond accordingly.

Growls are used by dogs in conflict, often times in defense of a bone or territory. In the study I read about, scientists played recordings of dog growls of varying sizes to the dogs being experimented on. Interestingly enough, the dogs were able to determine the size of the dog by only its growl. Scientists judged this by the response of the dogs, where in the case where the growl was from a dog smaller than the subject dog, the subject dog was more likely to respond aggressively with barking. However, when the growl was from a bigger dog, often times the subject did not respond or responded with whimpers – indicating its subjectivity to the larger dog.

I also read an article about a similar experiment where experimenters displayed pictures of a larger dog and a smaller dog on screen and played a recording of a growl. The subject dog was able to match the growl by looking at the image of either the larger dog or the smaller dog depending on the growl. Both of these experiments suggests that like the New World Sparrows, dogs can determine information about each other just by the calls of the other.

In conclusion, the two articles I read relates to what we have learned in class about bird songs and it made me wonder if all animals share the ability to determine physical information about one another just by their calls.

Sources:
http://www.sciencedirect.com/science/article/pii/S0003347209005016#sec2
http://news.sciencemag.org/sciencenow/2010/12/a-dogs-growl-announces-its-size.html?ref=hp

Posted by James Lin (2)

Deciphering Communication to Understand Behavior

One of the most interesting forms of animal communication comes from deep in our world's oceans. Once a mostly unknown topic, researchers are beginning to understand and recognize patterns of whale songs. Scientists have been using devices called hydrophones to distinguish sounds made by different whale species. Hydrophones were used in the past only for detecting underwater earthquakes, but sounds from ships, marine landslides, and whales have led to an increased interest in whale songs.

One of the most important things to note is that not only do different species of whales have separate sounds, but some species have different "dialects" depending on where they are from. For example, blue whales off the Pacific Northwest have slightly different songs than blue whales of the Western Pacific Ocean. Scientists have yet to determine if this difference is from learned behaviors or genetics. Once labeling a specific sound to a population of a certain whale, scientists can determine where the migration patterns and living preferences of these whales are. This is very important to the study of whales, as the previous method of counting and tagging a creature that can go as deep as 3000 meters underwater for 2 hours can be difficult. These Navy hydrophones can pick up whale sounds from up to 40 km away, or even farther, depending on ocean depth and terrain. One example in this article was how these devices picked up the sounds of an immense number of sperm whales who happened to be living in the Gulf of Alaska in the winter. Previously, all whaling records and other sightings have shown sperm whales in this region, but only in the summer months. It was thought that the Gulf of Alaska was too cold to harbor almost half of Alaska's sperm whale summer population.

Overall, the same techniques that we have studied in class on Raven are currently in use to analyze whale songs. This information is in turn used to determine where different whales like to spend their time and/or migrate to in the winter. I thought this was very interesting how it correlated to our in class discussions, basically deciphering whale communication to determine whale behavior.

Original Article- http://www.theallineed.com/ecology/06013129.htm

CROWS CAN COUNT?

You know that infants can count different quantities of blocks and that primates can count different amounts of bananas but did you know that crows can count different quantities of rainbow-colored circles?

Four animal behaviorists conducted an experiment to prove that jungle crows, Corvus macrorhynchos, were capable of discriminating between different amounts of the same sample. There was prior information about crows numerical ability. In this study they wanted to further test this knowledge by seeing if crows can discriminate between small and large quantities.

Eight birds were captured for the experiment, which was conducted in an outdoor aviary. Initial training was done with the birds to acclimate them to the experimental setting. The training used the quantity five as a control group, a group that stayed the same through the entire experiment. The first part of the training consisted of a cup with two pieces of rainbow-colored circles and a cup with five rainbow-colored circles, when the crows picked the cup with five it was given dog food as a reward. This was done until the crows made 15 out of 20 correct choices in two sets of ten trials. The purpose of this was to engrave in the crows brain that it should choose the five quantity cup. After the training process the crows were put through four rigorous tests.

These tests were done along with the training to show the results when different variables of the experiment were altered. The first test was done in the same process as the training except with new patterns that were changed with each new trial. The second test changed the rainbow-colored circles to different shapes. The next test presented the crows with different sized shapes, for example, the cup with the smaller quantity used bigger shapes and the cup with the larger quantity used smaller shapes. The final test was done to see if the crow would repetitively choose five items when presented with smaller items in one test and larger quantities in the next test.

After the long, grueling, agonizing, and slightly blood shedding experiment the following results were documented. When the crow was challenged to discriminate between the quantities of two and five, the crow learned to choose the five quantity after a few repetitions. The results the shape test showed that the altered variable did not change the crows ability to choose the five quantity cup. When the crow was tested to see if it would choose between the five quantity and a larger quantity, it always chose the larger amount of rainbow-colored circles.

So how would the crows do this? The reason how the crows chose the larger quantities was because of their visual cues. It is possible that each crow had its own reasoning for choosing the quantity that it did. When the crows were tested with the smaller quantities it was hypothesized that they could count up to four and remember that number, this was how they discriminated between quantities four and five. When, the crows were faced with larger quantities they were not capable of counting and simply just chose the larger amount of rainbow-colored circles. Now you must be wondering why crows would do this? It is believed that crows want to put all of their energy into gathering as much food as they possibly can. Now where do the animal behaviorists go from here? They would conduct the same experiment on the crows except without the initial training.

I just thought this article was an easy read but still very interesting.

Here is the link to the article http://www.sciencedirect.com/science/article/pii/S0003347211002338

Posted by Whitney Huynh (2)

Orangutans Play Charades

Humans are, in many ways, just slightly more efficient apes. We have tools, language, and cooperation allowing us to be the dominant species on the planet. Orangutans, however, already show behaviors all too similar to ours. They have strong bonds between individuals, have a unique social structure, and utilize crude apparatuses to obtain food. Now, though, it has been shown that orangutans enjoy a game of charades as much as any human.

While humans may use mime as a form of entertainment, orangutans use it as a form of legitimate communication. In an experiment by Richard Byrne of St. Andrews University, Scotland, it was tested how orangutans use gestures to facilitate a specific response. Byrne and his colleague, Erica Cartmill, put the apes in situations where they would need to “ask” for a specific foodstuff. The apes were presented with a highly appealing foodstuff, and a less appealing one.

The researchers themselves, though, did not always respond appropriately to the apes gestures, sometimes handing over the wrong food, or less than was asked for. The responses of the apes changed with every test. If the wrong results were achieved from their gesticulations, the orangutans would alter the signs to remove the misunderstandings. If the results were partially in favor of the orangutan’s aims, it would focus on already successful gestures and repeat them. The apes tried to avoid failed signs and only focus on those that got results.

In other words, orangutans have a language. It is crude and primitive, but it may shed light into the origins of human language itself. On its own, the experiment allowed for a bridge in human-ape communication. One can only postulate how far this will lead in interspecies communication as a whole.

Original article: http://www.world-science.net/othernews/070801_charades.htm

Posted by Jacob Lane (2)

Reef Squid and Chromatophores

Reef Squid and Chromatophores

The Reef Squid (Sepioteuthis sepioidea) is known to change color, shape and pattern to communicate with other reef squid and also their predators. They have an extensive number of patterns and colors they exchange between depending on the signal they would like to convey. The are able to communicate this way with the use of chromatophores. Chromatophores are cells in an organism which contain pigments such as xanthophores, erythrophores, leucophores, melanophores and cyanophores. Some pigments, such as iridophores, are iridescent and reflective which also give the Reef Squid a wide variety of choices. They are able to perform these actions through manipulating these chromatophores with their nervous system.

In a sense of danger, the Reef Squid can rapidly change colors to blend in with its surroundings. The ocean has a vast majority of different habitats and surroundings including colors. This gives us a good idea at how adaptive the Reef Squid is in terms of color and pattern changing.

Another way the Reef Squid communicates with other Reef Squids is through courtship. The video posted below shows how the squid attempts to attract a mate by changing to a white color. If the female agrees and likes what she sees, then she will turn white also. However, if the male squid doesn't meet her standards, then she stays the same color. If the male Reef Squid wants to get noticed by the one he has his eye on and other squids want to tread on his property, using his chromatophores, it can change to white on the half of his body that the female squid sees, and on the side that the other males are on, he can use another signal to warn the intruding male.

By using their nervous system, they can control their colors and patterns because of their chromatophores. They are able to communicate with predators and mates depending on the situation such as a threat, or even courtship rituals.

REEF SQUID COURTSHIP VIDEO

Post by: Ryan Dulmaine (1)

Sources: http://videos.howstuffworks.com/discovery/29078-the-ultimate-guide-octopus-reef-squid-courtship-video.htm
http://www.thecephalopodpage.org/cephschool/WhyCephalopodsChangeColor.pdf
http://en.wikipedia.org/wiki/Caribbean_Reef_Squid

Sexual Signals in Birds

An article published in Science Daily titled “Secrets of birds sexual selection revealed” discusses how patterned feathers in birds can play a huge role in warding off rivals and attracting a mate. It was previously thought that patterned feathers were only used for camouflage in birds. However, new evidence suggests that patterned feathers can also attract a mate and ward off rivals. Barred patterns, which are horizontal bars with a combination of dark and light pigmentation, were observed in the study conducted.

A study was conducted comparing around 8900 bird species. In this study, researchers aimed to compare barred plumage and other patterns on the body of males, females and juvenile birds. The researchers found that barred plumage was much more likely to appear only at sexual maturity. They also found that barred plumage does in fact play a huge role in camouflage. The researchers found that many birds had patterns on the front of their body instead of their back. Patterns on the front suggest communication during face to face interactions for attracting a mate, while patterns on the back are more useful for camouflage and hiding from predators.

This study shows that birds use their feather patterns to attract a mate as well as for camouflage to hide from predators. It is also interesting that about 90% of all bird species were examined in this study. Who knew that feather patterns in birds could serve as so many different functions.

Contraband Zebras

CONTRABAND ZEBRAS

Red bull may give you wings, but, discontent with just a few avian appendages, I bought two adult male Zebra Finches instead. I’ve named them Sherlock Holmes and Dr. John H. Watson- they’re usually collectively referred to as simply “The Detectives.” As with most birds, they’re very noisy, which doesn’t seem so bad until I explain that I’m keeping them secretly in a dormitory with a no-pets rule. Finches, fortunately, have a relatively quiet call compared to, say, parrots or parakeets. When singing together, they almost sound like muffled monkeys. They also need a lot less attention and interactive playtime. Thus I decided they’d make good dorm pets and purchased a pair at the nearest pet store.

One of the things I noticed almost immediately is their very distinct social behavior. They sing to each other very often for a variety of reasons. I’m still learning all of their little quirks and habits, but there are definite patterns to the types and timing of their calls. For example, they will, without fail, whistle, chirp, and “honk” very loudly in the mornings, as soon as the sun comes up. I’ve researched this behavior on my own for several reasons. Aside from the initial general curiosity, I also wanted to look in to possibly controlling this behavior in the interest of getting more sleep on weekends.

And so began my researching and experimenting. I first found out from several online pet-advice websites and blogs that birds are extremely photosensitive. Apparently, if I covered the birds’ cage with a towel or other opaque cloth, they wouldn’t notice the sunrise, and I could therefore postpone their morning chorus. I tested this, and it worked. Over the course of a few days I discovered it applied universally- I could cover the cage at any point in the day, and because of the decrease in light intensity, The Detectives’ noise and activity levels dropped almost immediately. I now had a solution to my problem, but not an answer to my original question- why do the finches sing in the morning? I also had a new question now – do they really sing in the morning, or is it a response to increased light levels?

On a website called “trib” that hosts science articles, I found out that one theory scientists have found support for is that male birds sing in the morning as a territorial warning to other birds. According to the website, every morning, birds will reaffirm ownership over their territory. They sing in the morning because during the morning hours, there will be less wind and heat to interfere with their songs. This makes sense, but doesn’t yet answer my last question about my Detectives. I guess if I had more time, I could do more experiments to see if the Detectives would still sing if I removed the opaque cloth while it was very warm around the cage. I could also turn on a weak fan to simulate a windy day to see if the singing would persist even when it would inevitably not carry.

In conclusion, birds are like miniature dinosaurs and are awesome. More on the misadventures of the Detectives in a couple weeks! Thanks for reading!

Posted by: Jonathan Flash (1)

sources:
http://trib.com/features/science/article_0386ede4-e3aa-5be1-818b-39d220a10b1f.html

(Also, Wikipedia)

EDIT:

Wow, nine comments. I feel like a celebrity on one of them short motion pictures on the TV. Thanks for reading my blog and voicing your support, everyone. If anyone would like to make a donation to show their appreciation, please contact me via email with your credit card number and PIN and I would be glad to help alleviate your bank account of any unnecessary funds.

Okay, sorry about that. I do appreciate everyone taking the time to read my post and comment. There were a few recurring ideas in the comments that I wanted to address:

1. Almost every post mentions the birds' circadian rhythm in relation to the morning singing.
2. Many people suggested noting the morning song and how it differs specifically from other calls that The Detectives make.
3. Some people voiced concern for the detectives in relation to:

• the size of the cage and the territorial morning call conflicting.
• using a towel too often and how that could affect the Detectives' biological clocks.

Now, I mentioned in the original post that I could cover the cage with a towel to quiet the singing at any point in the day. One thing I didn't mention as straightforwardly is that when I do this, the birds will start singing when I remove the cloth again. This observation seems to support the hypothesis that the birds are responding to a change in light intensity rather than the time of day. However, I have noticed something very interesting relating to this: when I change the light levels by removing the towel to "simulate morning," the Detectives sing the exact same song they do in the morning with the exception of one 2-second portion of whistled notes in the song. While this is a really intriguing observation, I have no clue what it means. More on that later, I guess.

Many people agreed that the specific type of song the detectives sing in the morning is of significance. I agree that it's definitely a very unique song compared to the sounds they make when they seem playful or scared. It's too early to say whether they use the song in other contexts. I'll keep my ears open and try to see if they use the morning song (or portions of it) at other times of day. If they do, it may relate to the stimulation they're getting from eating, bathing, grooming, or flying around, and that information could be important in decoding the true meaning of the detectives' morning song.

Finally, there were some comments expressing concern about the finches. In terms of using the towel to quiet the birds, virtually the only time I cover the cage is at night and when I clean their cage once a week (finches have terrible night-vision, so covering the cage means you can put your hand inside and clean it without them freaking out). Even still, though, I don't think cage-covering affects the circadian rhythm very much. My hypothesis is that the darkness, makes them hesitant to be as active, mostly because of the aforementioned lack of night vision.

Another concern was the cage being too small for a bird species that makes territorial calls every morning. I should first explain that finches are very social birds and will get depressed if they're alone in a cage. Unless they're hand-rearing a single finch from hatching, finch owners are always advised to have 2-3 or more finches per cage so the animals don't get lonely. As for the territorial calls, I didn't fully explain the articles I'd read properly. After looking through a few different articles about morning birdsong, I feel I can better define its theorized purpose now: The morning song, instead of being territorial per se, is usually meant to re-establish existing territory lines between males with the ultimate purpose of attracting a female to that territory. So I don't think the detectives will be having any border conflicts anytime soon. They're probably just horny, is all.

Poisted by Jonathan Flash (1)