In an article adapted from the NPR "Two Way" blog, scientists are seeing the largest number of Sockeye Salmon making their run up the Fraser river since 1913. An estimated 34 million salmon are making their way up the river to their spawning grounds, this is exponentially more than the 1.5 million expected for this year.This unusual population surge is not expected by scientists for next year. They believe that the surge this year was due in large part to the eruption of Kasatochi in 2008. This theory suggests that the ash from the eruption deposited large amounts of nutrients. This nutrient deposit would then lead to a diatom population boom, creating abundant food for young salmon. Long term patterns are expected to stay at the 1.5 million level for 2 big reasons: commercial fish farming and an increase in predators in the sockeyes' migration route. The small numbers of returning salmon in recent years sparked the Canadian to form a panel whose purpose is finding a reason behind the small numbers.
Four researchers, Sarah Cubaynes, Paul F. Doherty, E.A. Schreiber, and Olivier Gimenez, performed a study based on quantifying intermittent breeding in the Red-Footed Booby (Sula sula) population of Johnston Atoll from 1983-2002. This team captured and banded 11357 chicks and adults at there breeding colony. Their goal was to quantify skip-breeding patterns, first-time breeder's first attempts at breeding, and to quantify the survival of breeders, skip-breeders, and pre-breeders. They believe there's strong evidence in a correlation between the choice to skip a breeding season or start breeding at a later season, and the recent climatic changes from tropical storms, especially El-Nino.
Measurements were taken of the local mean sea surface temperature (SST) of Johnston Atoll in order to find the effects of SST variation on pre-breeders choice to postpone breeding for a season or if it caused breeders to become skippers. They also measured survival rates for the different life stages that were studied and how at what age pre-breeders first begin to breed.
The data used to form models included measurements of the transition probabilities from Pre-Breeders to Breeders, from Breeders to Skippers, and finally from Skippers to Breeders again.
Their multi-state models found that El-Nino's climatic changes in SST did in fact impact Red-Footed Booby's and overall increased the skipping behavior of less fit Booby's for a years breeding season. It was also observed that first time breeders would actually begin breeding with the presence of increases SST levels. This meant that the breeding season's environment does not weigh on the cost of reproduction for the Red-Footed Booby's as much as competitive interactions do between they and their colonies experienced breeders.
Most humans have a sense rhythm (some better than others) but where did we learn how to dance? And are we the only organisms that can? These questions have been posed in the light of a recent study done on birds and their ability to dance. We have just learned in our Animal Communication class that some song birds have the ability to dance as well as sing in order to attract a mate. These song birds, however, do not have rhythm and cannot dance to songs with a beat. Studies done at Neurosciences Institute in San Diego and Harvard University both confirm that the only type of bird that is capable of having rhythm are birds that have the ability to learn words and mimic sounds- parrots. Two main subjects of these studies are Snowball the Sulfur-crested Cockatoo and Alex the African Grey Parrot. Both of whom are excellent dancers. Researchers looked at many videos of dancing birds on Youtube and eliminated those that were tampered with in one way or another and focused on the ones that showed real evidence of a parrots ability to detect rhythm. Snowball the cockatoo was tested in a lab setting to determine whether he could pick up beats when music was slowed down or sped up. Sure enough, the Youtube birds appeared to keep a beat and Snowball picked up the new rhythms and danced accordingly. The researchers involved in this study hypothesize that dancing and rhythm are some how linked to the same part of the brain which aids in vocal learning (as it is in the human brain.) One of the leading researchers also noted that this behavior is a little strange as parrots in the wild are not known to dance to the songs of other birds. Although quite facinating, this study as lead scientists to wonder where this ability to dance came from and what other vocal learning animals might have the ability to dance.
Many species are known to produce alarm calls in response to predators or other perceived threats. There are a variety of questions and hypotheses about the purposes of these signals, how they evolved, and the ways in which calls can vary within species. For example, did signals evolve to scare away predators or to warn other members of a group? Or are they simply a response to the distress caused by the predator? Can different threats elicit different response signals? If so, how and why do they differ?
In the paper “Predator-deterring alarm call sequences in Guereza colobus monkeys are meaningful to conspecifics,” Anne Marijke Schel, Agnes Candiotti and Klaus Zerberbuhler discuss the alarm calls of Guereza monkeys. Two main predators of Guereza monkeys are leopards and crowned eagles. The calls of each of these species result in different responses from Guereza monkeys. For example, when they hear an eagle shriek, the monkeys are more likely to look towards the sky than when they hear a leopard roar. In addition, different alarm calls are produced in response to the leopard than to the eagle. Guereza monkey alarm calls consist of sequences of roars. When responding to leopard roars, monkeys produce a large number of short roaring sequences while when responding to eagle shrieks, they produce a small number of long roaring sequences. There are two hypotheses regarding the difference between these two alarm signals; it could be the result of different levels of threat or it could be a way of telling other monkeys what type of predator is coming. The fact that monkeys are able to recognize the difference between the two alarm calls and respond to alarm calls in similar ways to which they respond to the calls of the predators indicates that the two different calls contain real and useable information about what type of threat is present.
Schel, Candiotti and Zuberbuhler concluded that the alarm call of the Guereza monkey has two main purposes. The first is to chase predators away and the second is to communicate danger to other monkeys. The fact that alarm calls for leopards and eagles are different is helpful in both of these contexts. The alarm call in response to the eagle is more threatening and this makes sense because Guereza monkeys try to chase eagles away more often than they try to chase away leopards. In addition, the difference between the calls lets other monkeys know what type of danger is present.
You ever play tug of war with your dog and it gets so riled up it starts growling? Or how about when you go to grab its bone? A dogs growl can be pretty intimidating. My dog Stryder is a 115lb male pure bread Golden Retriever, just adorable, but when he growls you quickly realize that's a big dog growling at me. Now he's a protective dog over my families house and family members so when another dog comes in our yard he goes on the defensive, but little did I know that his growl tells other dogs a lot more things than I could have thought of.
Recent studies have found that dogs barks are far more complex to the human ear. Now that may sound like an erroneous statement, but scientist have found that dogs receive special information from the god that is growling, something that has never been found before. The three test that were used to see if dogs growls really were different had the dogs growling during play (while playing tug-of-war), while a stranger approached and while guarding a large meaty bone. These growls showed the scientist many things, such as confirming that a dogs growl tells the listener how large and heavy the dog is, but the second part of the experiment showed the scientist something very strange.
For the second experiment each dog was given a large meaty bone in an open room and the recordings of the 3 different growls were played through a hidden speaker. They 3 types of growls were the ones that showed the strange event. The play growl was significantly different when looking/ analyzing the growls recordings and showed no reaction when the dogs were chewing the bone. But the stranger and guarding growls looked identical, yet the dogs reacted completely different. As the scientist played the stranger approaching growl the dogs showed no notice of the noise other than an ear perk, but what they fully showed aggressive reactions towards was the dog guarding bone growl.
Since the two recordings of the stranger growl and bone growl were identical, scientist have theories that dogs can sense the inner emotional state of other dogs, and that aggressive "get away from my bone" emotional state comes out.
Auditory signals undoubtedly play an important role in animal communication. Presumably as an adaptation for noisy environments, the human brain has developed a tendency to "restore" parts of speech or other noise that may have been blocked by a different noise, creating the illusion that no interruption occurred. This is known as "auditory induction" and "perceptual restoration." This phenomenon has also been observed in animals such as cats, tamarins, macaques, and starlings. One study published in Animal Behaviour examined auditory induction in Hyla chrysoscelis, Cope's grey treefrog.
The study used females to investigate whether these frogs show a similar ability to fill in gaps in various calls in order to facilitate communication. It was found that signals with these gaps were less attractive to females than gap-less signals. This is important because auditory signals play a large role in frog mate choice and mating rituals. However, the results of the study indicated that the "continuity illusion" was not present in these frogs -- in other words, the females did not "hear" sounds that were not there.The researchers did note that their experiment was very limited, because not only did they only study one species of frog, but also their work was not comprehensive. It is possible that a similar type of illusion is caused by other factors not yet investigated.
The authors also noted that how frogs learn and use calls is very different from songbirds and primates. For example, frogs do not appear to learn or recognize any of their calls, and demonstrate less sophisticated social behavior. This makes frogs valuable study subjects, as well as dangerous ones, because they have these differences. Further research into frog vocalizations, as well as into the phenomenon of auditory induction, could be very useful in studies on animal behavior and communication.
Many species in the animal kingdom rely heavily on their appearances to attract mates, however most of their appearances are derived from genes that have been selected for, as a result of successful matings. This form of sexual selection is very important to most birds, as most species chose mates from preferred appearances and/or displays. However, new studies have shown that Flamingos (Phoenicopterus roseus) actually apply natural forms of pigments to their feathers to boost their appearances and attract mates!
According to this study by Juan Amat, new evidence supports that birds transfer color pigments from their uropygial glad for cosmetic reasons. Although there is evidence that the colors of feathers change by abrasion, photochemical change, and staining, this transferring of pigments to their feathers has been displayed in greater Flamingos in Spain. Amat has been studying Flamingos in the field to compare seasonal variations in plumage color in relation to courtship activity. He also looked for the actual pigments and behavioral displays used to aquire and maintain the pink color Flamingos are best known for. Lastly, he compared all of these factors to annual reproduction patterns of egg laying specifically.
He found that similar to other species of birds that rely on sexual selection to determine successful reproduction, the plumage of Flamingos was more colorful during breeding season. Likewise, soon after breeding season ended, plumage began to fade. He also observed that during the breeding season Flamingos performed a rubbing behavior in which they rubbed their head on their neck, breast and back feathers to transfer carotenoids from their uropygial glands. This behavior of "applying natural make-up" assisted in making their feathers more colorful. This data suggests that this importance of cosmetic coloration is directly related to mate choice in Flamingos.
Doc is one of the animal mascots for the Massachusetts Academy of Sciences. The MAS runs out of Morrill here on the UMass Amherst campus. He lives in Peg Riley's lab. Doc is only about a year old at this point, which means he is in the very early stages of learning how to communicate. African Grey Parrots are capable of learning complex behaviors, understanding language, and learning to speak. So far Doc's progress is coming along well, and he has a few words like "Good Boy!" and "Hello" mastered. He will also give kisses if he really likes you. He just keeps learning more and more!
Doc is the same species as an even more famous parrot named Alex. Alex has been a huge part of avian studies. He learned over 100 vocal labels for different objects, actions, and colors. He can also identify objects by the material they are made of. To learn more about Alex go to this link: http://www.alexfoundation.org/alex_the_parrot.html
In addition to his vocabulary, Doc is being trained to respond to the clicker method. Everytime Doc does something correctly he is given a raspberry and a clicking sound is made. This is used as positive reinforcement for his behavior. This will later be used to train him in some more complex tricks beyond just dropping the correct toys in to his bowl. Doc is being trained this way so that the Massachusetts Academy of Sciences can have him be a social bird that can be a big a part of science-outreach programs. For more information about Doc go here: http://www.massacademysciences.org/content/say-hi-doc
Sexual Communication in Cane Toads, Chaunus marinus: What Cues Influence the Duration of Amplexus
When you look for someone to date do you look for someone tall or someone short? Do you notice the one with the dark hair or the light hair? Do you like someone with a sturdy stature, or someone long and lean? If we had stripes or spots, which do you think you would prefer? We are not the only animals who choose our partners. Most species go through a process of sexual selection when choosing a mate because wild animals must have optimal survival and reproduction to continue populations of species. The quality of a mate is represented by the compatibility of genes. To assess the quality of a mate one must interact with other members of the population. Communication through courtship is an important step.
Bowcock, Brown and Shine studied Amplexus or the reproductive position of Cane Toads in 2007. The selection of mates by males was in question because during the mating season, males will mount any female that is the right size. He will do so even if the female is unable to reproduce or if she is unwilling. Unwillingness is not what will deter a male Cane Toad from maintaining amplexus however. This is a problem for the species because it eliminates sexual selection, possibly limiting genetic variation and natural selection. By mating with females who are unable to reproduce the males are wasting energy and sperm by mating with them; it is not conducive for a high reproductive rate. The calls of Cane Toads where analyzed during breeding season to see if there was a trigger for the calls. The result being that the amplexus position initiates the call in males. It was found that female Cane Toads are mute and therefore have no auditory call. Female Cane Toads use flank vibrations for sexual communication. The stimulus of amplexus dismount was the call of another male but only if its call was longer than the mounted male’s. This suggests that the male with the longer call has outcompeted the male with the shorter call. To dismount because of this seems like a useless response however because the males are already mounted.
To check out this article: http://www.sciencedirect.com.silk.library.umass.edu:2048/science?_ob=ArticleURL&_udi=B6W9W-4RWC89K-4&_user=1516330&_coverDate=04%2F30%2F2008&_alid=1505489860&_rdoc=6&_fmt=high&_orig=search&_origin=search&_zone=rslt_list_item&_cdi=6693&_sort=r&_st=13&_docanchor=&view=c&_ct=4617&_acct=C000053443&_version=1&_urlVersion=0&_userid=1516330&md5=4bc1cef8a54a836159b6a32bac50fa8f&searchtype=a
Many studies have been done on mutual display among birds associated with partner choice but not much has been done in studying what happens beyond that to keep the pair together. For instance not much is known about the behaviors that keep a monogomous pair together beyond courtship. This article suggests that private forms of duet exist in monogomous birds. Using Zebra Finch as a study subject they recorded communication between mates from inside the nest boxes. Two sequences were measured, the meeting seqeunce and the sentinal sequence. It then had to be determined whether these sequences fit the ctriteria for bird duets: call alteration, temporal precision and the relative participation and initiation by each partner. It was found that within these bouts three types of calls were used by both male and female at the nests, whines, tets, and distance call. Although it may not show the level of complexity that some songbirds have it was found that privated forms of duets do exist as part of display behavior in monogomous birds. Both sequences meet the criteria for bird duets, they showed temporal precision and a high level of alternation between mates. It was also found that these duets are not sex specific but rather location specific ie inside the box or outside the box. These interactive sequences represent a private form of vocal duet that may facilitate bond maintenance.
On a hot summer night, you hear the familiar and annoying sound of a mosquito that flies somewhere in the darkness. However, this dreadful buzz can actually be a song of love between two mosquitoes. Researchers at Cornell University have shown that male and female mosquitoes of the species Aedes aegypticontinuously alter their wing beat frequencies to match each other’s during mating behavior. They culminate at a specific frequency, achieving a romantic duet.
Previous research suggested that male mosquitoes couldn’t hear above 800 Hz. Females were also considered to be entirely deaf. However, this experiment revolutionized our knowledge of both their mating interactions and sound perception. Researchers tethered flying mosquitoes and moved one partner past the other, who was stationary. Recordings from a particle velocity microphone revealed that both sexes responded to each other by synchronizing the frequencies of their wing beats. They ultimately culminated at 1200-1300 Hz, which is well above the fundamental wing beat frequency of 600 Hz for males and 400 Hz for females. It also exceeded the established hearing range for both sexes. When the mosquitoes were deafened, no matching occurred. This provided evidence for the acoustic transmission of information. They further tested this hypothesis by removing the flying partner. Signals were electrically generated through a probe that imitated a natural flight pattern. The mosquitoes still coordinated their frequencies, showing that only sound is necessary.
Confused by previous assumptions about the hearing range of mosquitoes, researchers also inserted electrodes into the Johnston’s organ to once again test perception. They utilized a different filter than in previous experiments and found that both males and females respond to frequencies as high as 2000 Hz.
Another interesting development involved differences between mated and unmated females. A greater number of unmated females responded to playback experiments involving a 1400 Hz pure tone than did mated females to a full male song. Consequently, the acquisition of a mate leads female mosquitoes to be less responsive to other males.
Knowledge of this romantic courtship can help control mosquito populations. One method is to release sterile males into a population, but their diminished fitness may be shown in their ability to match frequencies of females. They are therefore unattractive, hampering the effectiveness of population control. This research can later provide methods of enhancing the desirability of sterile males and thus increase the efficiency of population control. Summer nights may even be a little less noisy.
To read the popular article, click here. To read the research article behind it, click here.
He studied these curious sea birds for over two decades. He found that the older boobies in a nest, only 4 days older than the others, pecked at their younger siblings incessantly. They were even pecked up to 60 times a day! The older birds would also take their food away from them. In the first week of hatching he estimated the young birds lost about 17% of their share of the food. If food gets scare the older birds will go as far as killing the younger ones. The parents don't even intervene to stop to violence.
The results showed that at first the young birds were submissive, incapable of fighting back, and had a stress hormone present in the bloodstream. However, by the time they are ready to fledge, they have gone through a growth spurt so they do not differ in size and over their lifetime they have the same amount of offspring. They end up living normal lives even after this traumatic childhood. Drummand has speculated that evolution might have favored some kind of compensation for poor starts in booby life.
-Katie Cyr (A)
Adelie Penguins: "Partners For Life"
Adelie Penguins generally tend to be very good couples but suffers from separation due to their migratory behaviors. They are usually monogamous but pair up with their partner from the last season at the same place to breed. Adelie penguins are known very well for their ability to find their way back to exactly where they mated. They usually mate at their natal breeding ground. It is still unknown how Adelie penguins are so good at finding their way back to the breeding grounds but it had been suggested that they follow the direction of the sun to navigate.
The male Adelie penguin usually returns to their natal mating ground at first. Upon arrival, they create a breeding nest with mostly stones and sometimes feathers and bones. Stones become scarce during mating time since they are used to build walls. Thus it becomes common for Adelie penguins to steal stone from one another when they are not looking. Male penguins express their choice to mate with a female by rolling a stone at her feet.
Each year, the male recognizes their female mate from thousands of other mates by their voices and cries. If the female cannot find its male mate at the colony, then she goes for another male. But if the male mate ends up showing up later, the female will go back to mating with her original partner. On the other hand, if a female is late to show up at her colony and finds her mate with another female, she will attack and drive the intruder away.
Lizards are generally perceived as "unloving" parents, cause once the eggs are laid, the offspring are on their own. Yet, nature has again provided examples where species of lizards would form family groups. The article Lizards Have Family Values by O'Hanion describes the desert night lizards that group together under the logs are often genetically related, which can be proven through DNA analysis. This familial grouping also seem to coincide with lizards that have viviparity (live birth rather than egg-bearing), which results in fewer offspring that may live with longer lifespan. These desert night lizards do bear live offspring and tend to live long, as the subjects studied in the articles were found to be about 20 years old. Basically, these lizards are also playing the parent game in order to insure their species' survival, just like the other mammals and birds that are so different in physiology.
For me, I never heard of lizards actually forming family groups to care for young and each other (although one time I have heard that a group of related males worked together to obtain females and deterred other competition). Although the details weren't exactly clear on the exact behaviors involved (tested mostly on DNA of groups huddled during winter), it provides compelling evidences that a family system can be established. Even siblings could recognize each other! Since this was newly discovered, the actual interactions within a family system is not really known. Yet within a family system, there has to be some kind of communication just like in every family group. Do they communicate through a combination of movement, visual cues, sounds or pheromones? Do these communications further bond the family system? How does a lizard family group interact with each other? I am sure with future research that these questions would be answered, now that people know lizards can have a family just like us… just a cold-blooded one…
Differences in Acoustic Directionality Among Vocalizations of the Male Red-Winged Blackbird are Related to Function in Communication
Most people hear birds singing on a regular basis especially during the spring. In the past when I heard various bird calls I didn't think to deeply about them. I never thought of the songs as a means of communication. I also never considered the possibility that different bird calls were selected against for the most efficient means of communication. I looked at them from a human perspective rather than a birds.
After reading a paper written by Gail L. Patricelli, Marc I. Dantzkerand Jack W. Bradbury I gained some insight into the differences in vocalizations birds make and the selective pressures that guide these differences. The authors of the paper set up an experiment to test the directionality of different calls that male red-winged black birds make. They made man made perches in the birds natural habitats. They surrounded the perches with three cameras pointed toward the center and eight different microphones in a circle around the perch. They then recorded different types of the red- winged black birds calls. The experimenters used the recordings they took to measure the directionality of the calls. Calls with higher frequencies are more focused in one direction while lower frequency calls are less focused.
They found that different calls have different levels of directionality. Calls used to alert fellow birds about danger were the least directional. While calls used during courtship were the most directional. The experimenters believe that the calls are selected against for the most effective communication for the specific scenario. The alert calls are the least directional because the bird wants to warn the most other birds it can in the area. The courtship calls are the most directional because the bird doesn't want other birds eaves dropping and stealing it's potential mate. The experiment suggests that the directionality of the calls are related to the message the bird wants to send.
We all know that squirrels hide away food to store and recover it at a later time.Some may also know about magpies; birds that are known to steal shiny things, like metal, and hide them away.Scrub-jays, a member of the corvid family like magpies, also hide, or “cache” food and recover it at a later time.By observing the caching behavior of scrub-jays in the lab, more about the amazing social cognition of birds has been discovered.
The corvid family of birds, which includes jays, ravens, crows and nutcrackers, has already been shown to have incredible memories.These experiments, however, reveal that birds can think and analyze situations involving other birds and act accordingly, as well as plan for the future and recall the past.
One of the most amazing results from the study is that birds can in fact think about the future.In one test, scrub-jays were presented with 2 cages.The first cage was one in which they were previously denied breakfast, and the second was one in which they were fed as normal.Given the opportunity to steal and cache food, the birds opted to hide the food in the cage that they had been hungry in, possibly in anticipation of not getting breakfast again.
Additionally, the scrub-jays, like squirrels, can track the passing of time to ensure that they return to a cache of food before it spoils.
Finally, it was the social thinking abilities that struck these scientists.If a scrub-jay knew they were being watched by another bird while caching, they would either wait until the other bird looked away to hide their stash, or hid the food but returned soon after to move it somewhere safer.Previously, having an episodic memory, or being able to recall a moment versus a skill or a fact, has been considered a human ability.These findings are challenging how scientists view the mental capacity of birds.
The last point that got me thinking about intelligence in other animals and species was when the article pointed out that birds and mammals split on the tree of life some 280 million years ago. The structure of their brains is also significantly different.However, the ability to think flexibly is shared so the scientists argue that such intelligence must have evolved separately but somehow converged to achieve the same goal of managing social interactions. Pretty crazy to think about, isn’t it?
If you've ever been a dog owner, you'd know that it can be hard not to anthropomorphize your pet's behavior, when their personalities and emotional states seem so much like ours. A recent study published in Current Biology suggested that the role emotional state pays on decision-making in dogs is very similar to humans. They even did a series of experiments to test whether or not a dog can be an optimist or a pessimist. They performed the experiments on shelter dogs in Britain. First they observed a dog's reaction to being isolated for a period of time to see if it would respond to separation-anxiety. Anxious behaviors included barking, jumping on furniture and scratching the door. Then they placed two food bowls in two rooms, one full and one empty. Once the dogs learned that the bowls were sometimes empty, sometimes full, they began placing the bowls in ambiguous places. Some dogs would race to every bowl, hoping to find food, while others did not. The researchers suggested that the first type of dog had an optimistic outlook, and the second type a pessimistic outlook. They also found that the more separation-anxiety a dog exhibited, the more likely it was to be a pessimistic dog. A pessimistic outlook might not be apparent in other characteristics of the dog, like speed, agility or learning capability. What this study suggests, a dedicated dog person could've told you all along: that dogs have distinct personalities and their mood affects their behavior just like ours.
-Jane de Verges (Group A)
Monkey See, Monkey Do?
Throughout my studies of animal communication and animal behavior, I have often wondered whether the results of field studies can be considered valid, since it would seem intuitive that the act of observing animals could significantly alter their natural behavior.For example, do birds that are being watched by researchers consider the observer to be a threat?If so, they would most definitely display more aggressive behavior than usual.To investigate this question, I read an article entitled Does watching a monkey change its behavior? by Crofoot et al. (2010).
According to the article, the issue of observer response has been a large concern among researchers for many years.To minimize the effect an observer has on their animal of study, several techniques have been utilized, many of which have proven inadequate. Possible solutions have included hiding or disguising oneself in the field, or using cameras and remote data collection methods; however these methods limit observers to a fixed location and cannot provide the detailed behavior data gained through direct observation.The most trusted and often used method to prevent observer effect is habituation.Carpenter (1934) first proposed that “with sufficient ‘neutral exposure’, animals would become accustomed to and eventually ignore human observers.”
To test the method of habituation and its validity and effectiveness in field studies, Crofoot and his team used data from an automated radiotracking system to test whether habituated capuchin monkeys altered their behavior when a human was present.In the months of July and August, Crofoot’s team captured seven capuchins belonging to four social groups and fitted them with radiocollars.For the next several months, the team tracked the activity and behavior of these capuchins remotely, without any human presence.The study animals then experienced five months of regular contact with human observers, after which they seemed fully habituated to the presence of the researchers.After this habituation period, the observers followed the capuchins throughout their habitat making behavioral observations similar to those tested using the radiotracking system, the only difference being the researchers’ presence in the field.
What Crofoot found was that after a significant period of habituation, observer presence did not significantly affect any of the behaviors investigated.However, during the period of habituation, the behavior of the monkeys was significantly different than the observations made by radiotracking prior to this period.These data show that the effects of human observers can be great, but through habituation, these effects can be significantly minimized.I found it interesting that I had never heard of habituation when studying animal behavior in the past, since it seems to be an extremely important preliminary step in order to produce experiments in which the results can be trusted.
A white crowned sparrow is just beginning to fledge, surrounded by a barrage of birdsong from its own species and others. As long as it is sufficiently exposed to its own specie's song during this stage, it will be able to learn that song when it matures. If it is kept isolated, the bird will never learn- even if it is exposed to the song ages later.
A human infant, in its first year, is exposed to a variety of calls too- from its parent's, from television characters, even pets. Yet even if speech has not fully formed by their first birthday, a child will have committed to its native language- any vocal sounds it has not been sufficiently exposed to during this time, even if they are common to other languages- will be impossible for the child to comfortably produce, if not impossible.
Although humans and birds diverged ages down the evolutionary ladder, striking resemblances between the way babies learn a language form copying their parents and songbirds learn their species' calls from tutors have urged researchers to look more closely at how birds learn songs for clues at the origin of vocal language. The process is so complex, even if it evolved separately between the two species, one system might well resemble the other. And besides, where else could vocal language have come from? Answer: where non-vocal language came from.
Scientists have long studied apes for clues on language (our ancestors make a natural choice.) But have been frustrated by ape's inability to pick up language. Though they might learn complicated gestures (such as sign language) and use that to communicate pointedly and easily, after a lifetime of trying you might, if you're lucky, get one to understand three words. But gesture might be more closely linked to vocal language than previously thought. The language centers of the brain are located on the left side, which also coordinates movements on the right hand side of the body. Apes (and humans!) have a strong tendency to use their right hand for communicative gestures, such as those showing information or interest. This holds true even if the animal/person in question is ambidextrous or left handed! Yet there is no such tendency for non-communicative gestures like head-scratching. This suggests that gestures are done with the right hand because they are linked to the language-centric parts of the brain. And here's where it gets really interesting: if you separate pointing into two categories, imperative (for "I want this, begging, etc.") and declarative (which shares information, requires seeing the other person as a PERSON, and is accepted as higher-level communication), then declarative pointing is much more often accompanied by a word or call than imperative pointing! It seems like higher-level communication (through gestures) naturally leads to vocal language!
Perhaps language originated from gesturing, and as evolution took its course it became mostly or entirely vocal in some species. Who knows, maybe if it was advantageous humanity would evolve beyond gestures entirely. So where did language originally come from? No one is sure. But it seems like if we want clues on how it works now we should look to our avian cousins, and if we want to know how it worked then we should learn from our ape ancestors.
Unlike smaller mammals, African elephants have few predators in the wild. These mammals stride majestically through Africa’s forests, grassy plains, and bushlands. Although much is known about the animal, little research has been conducted in the field elephant calls. For example, African elephants are known to roar in the presence of lions. Recent evidence has also showed that these elephants tend to avoid contact with African honeybees. Elephants were observed avoiding trees with honeybees. A recently published article, analyzes the behavior of African elephants in response to bee sounds.
Researchers recently found that the sound of African honeybees causes African elephants to produce warning calls. These warning calls result in the elephants retreating. Researchers first played clips of bee sounds. This elicited a distinct rumble alarm sound from the elephants followed by a retreat. In second experiment, researchers played the rumble alarm sound to a group of elephants. Afterwards, the elephants retreated from their position.
Researchers are still trying to figure out if this alarm call is only in response to bees. It possible that through hundreds of years of interacting with one another, that the elephants have developed a specific call for bees. Analysis on the rumbling sound has yielded a few theories on the sound itself. Scientists propose that the sound may serve to knock the bees out of the air, and even serve as a learning tool to teach the young about prey. Further testing may prove useful in determining the effects of using beehives to deter elephants that raid crops.
A group out of the University of Texas, Austin, tested some variables that go into the female mate selection of Tungara frogs. Males of this species can often be heard using dynamic signaling to call females from quite a distance a way. The males have two somewhat distinct calls. The more preferable whine chuck sounds like a higher pitched whine followed by a sharp chuck or series of chucks and the less preferable monotonous whine. Previous research had been done on which method of calling was the most preferential so this group, continued on this path testing timing and volume of these signals. The group wanted to test at which point a female mate choice was permanent. Using over 350 female frogs the researchers set up a stable testing environment. A football field like arena was set up approximately 2 meters in width and 3 meters in length. At either end of the arena there were target speakers that would play the whine or the whine chuck simultaneously. In the middle was a circular area called the release point where the females being tested were held under a small, perforated cone. “Switch boundaries” (equivalent to yard lines on a football field) were drawn at 60cm, 75cm, and 100 cm. The experiments were run in a very controlled fashion to reduce errors in observations. In the control, the on speaker played the whine chuck while the other played the whine. The females were individually put in the center of the arena and held under the cone for 3 minutes while the male signaling was played. Once the 3 minutes were up the cone was release, the speakers continued to play and the female was drawn to one of the mate calling speakers. All 373 females were tested in the control and in all 373 control tests the female chose the whine-chuck speaker. This told the researchers that not only was the whine-chuck call the more preferable one, but that the females would actually travel to the speakers 100% of the time.
In the next 19 experimental procedures the Researchers manipulated the speakers volume, and switched the signaling calls once the females reached one of the switch boundaries. For example, in Experiment 1 once the female was released and reached the 75cm boundary of the whine-chuck speaker, the signals on the speakers were switched and the now distance whine-chuck speaker was amplified 2 decibels. This procedure was done for each of the 373 females. The next 18 experiments were all manipulations of experiment 1 that played with the volume and the distance of the females. In almost all cases a percentage of females switched paths and went to the distant whine-chuck speaker. This showed the researchers that the female mate choice was not permanent at any of their boundary distances. Even though in some cases this percentage was small, a 100% permanent mate choice at a certain distance was never achieved. Some Issues were noticed within the results and in the way the researchers quantified the data. The way the data was organized and quantified made it very ambiguous on which of the variables (distance or volume) was the prominent variable in choice reversal. A new experimental procedure testing one specific variable at a time should be done to determine which one is the more confounding variable.
Patrick Salome
Humpback Whale Swims a Record Distance
I had little knowledge that whales traveled extremely long distances, and found this article to be eye-opening and very interesting. Among the many species of whales, Humpback whales (Megaptera novaeangliae) are known to have the longest migration distances. The article I read detailed a unique single female humpback whale that travelled more than 9800 kilometers from a breeding area in Brazil to those in Madagascar.
This whale’s journey was recorded by a biologist at the College of the Atlantic named Peter Stevick and the finding is published in the journal Biology Letters. His team recorded that this particular whale’s journey was 400 kilometers farther than the previous record distance.This whale was first seen off the coast of Brazil, where researchers captured an image of its tail fluke and took skin-biopsy samples. In 2001, this same whale was photographed by a tourist on a whale-watch boat near Madagascar. Furthermore, there were other noteworthy unique details about the journey that intrigued Stevick and his research team. When humpbacks travel, they alternate between high latitude feeding areas and low latitude breeding grounds while keeping the longitude more constant. This humpback did almost the exact opposite, spanning 90 degrees of longitude while crossing several different breeding zones. Also, the farthest distances traveled are usually recorded by the males, because females remain attached to their respective breeding sites.
The intriguing part of this article is that the reasons behind this humpback whale are unexplainable. The female could have been responding to distant calls, seeking out new breeding grounds or simply have been wandering astray. Although humpback whales are thought of as being very well studied, surprises such as this article leave scientists with a lot of questions about the behavior of this species. This article is one small example of how little knowledge humans have about the world’s biggest mammal.
Communication through signals, displays, and songs are some ways animals communicate with each other. This communication is important because it helps animals of the same species (and sometimes of different species) live together peacefully. A lack of communication though can cause many problems. Male jumping spiders (Phidippus clarus) perform displays and push each other back and forth like sumo wrestlers. These displays help each male gauge how closely matched they are and fights rarely occur. The displays allow the males to solve things before any injuries come about. Females on the other hand lack these displays. What happens in this case?
Female jumping spiders have different rules for fights. Females have no displays or sizing up of the competition. Instead, they go right at each other, and they go out for blood. As soon as the battle commences, the females will fight till they are unable to fight because of injury or death. The other part to this style of aggression is that the victor was not always the bigger stronger female. When researchers saw that the stronger spider was not the one who would generally win, they created a new hypothesis.
Females live in nests and make sure to protect and take care of their place of residence. Male jumping spiders are nomads. This means that they can change living space at anytime. Females on the other hand value their nests much more. To test this hypothesis, researchers set up a series of fights between nest owners and the homeless. The owner of the nest was not always the winner though. What they found was that the female closer to maturation was the one who would typically win because they use the nest as a place of protection. Before a female can reproduce, she must molt and at this time she is highly vulnerable to predators. She uses her nest as a safe havenand the closer she is to maturation and this process, the harder she will fight to pass on her own DNA.
Communication is important for animals to live their lives. Lack of communication on the other hand has serious consequences with one of them being the ultimate price, death.
In an article in Scientific American published, October ,12, 2010, recent studies show that an octopus can use its tentacles as individual vessels of control. Everybody knows that Octopus are really smart. They have been seen to show insane intelligence even going as far as tool usage. What this new study shows is that each suction on the tentacle of an octopus can be used individually to twist, or hold at different pressures. this provides an incredible amount of dexterity and maneuverability. The octopus uses each sucker by allowing different amounts of water in which changes the pressure and the strength of hold that each sucker has. This allows the octopus to twist things up to 360 degrees and support its own body weight with only a few select suckers. This adaptation is extremely beneficial to the octopus as it provides control and the ability to use it's environment more efficiently. The pressure that can be exerted is determined by how much water is let underneath the sucker, creating for negative water pressure. This study was determined in lab tests examining the usage of suckers of octopus and other marine life. The pressure will vary given on suction size and amount of water, but if several suctions are involved it will surely support the animal's body weight and be essentially impossible for any prey to dislodge a sucker. I thought that it was really amazing to read this. I work at the New England Aquarium and our octopus could actually climb out of his tank and into the tanks of other fish to eat them before returning to his own. This was always so amazing to me. Paired with that kind of intelligence and the physical ability of being able to use the individualized suckers they are a serious marine animal to contend with.
As human beings we are able to manipulate our environment to deceive a viewer by altering the perspective. One way many people do this is by wearing black to appear slimmer.It turns out that we may not be the only species that does this.The Great bowerbirds are the first known non-human animals to create scenes that alter visual perspectives for viewing by other individuals.
Great bowerbirds are known for their elaborate mating displays and constructions.New research done at Deakin University in Queensland, Australia by John Endler and his team, has found that male great bowerbirds actually build staged scenes that make themselves look larger or smaller than they actually are deceiving the females.
Male great bowerbirds build bowers.A bower consists of an avenue and a court.The avenue is constructed by two rows of tightly packed sticks that opens onto a court.The court acts as a stage for the males to perform their displays for females.The avenue causes there to be only one location for females to view the displays.Males carefully place pebbles, bones, and shells in the court with smaller objects towards the front and larger objects towards the back.This placement causes the objects to seem big and the court small.This causes the males to appear larger in size.The male will perform his visual display and if the female is impressed she will mate with the male right on the stage.
Endler and his team rearranged the items in the courts.But within three days the items were back to where the males had carefully placed them to begin with.This study reveals that these birds not only are using structure and color but are also using perspective by manipulating the geometry of the arrangements.
Its amazing that these birds are able to recognize perspective and were able to utilize perspective to deceive females.I wonder if females will ever catch on to the tricks these males are creating.
