How Shrimp Communicate

How Shrimp Communicate

Animals communicate in a number of different ways. Some species use a gesture or body language, while others depend on vocalizations such as calls or songs. Until recently little has been known about how the critters that dwell the ocean floor communicate. In order to learn more about communication in the deep sea, scientists examined the behavior of the 8-inch long mantis shrimp.

Scientists were able to examine communication between the shrimp using a coupled audio-video system, a hydrophone array, and an autonomous recording unit. They found that male shrimp create rhythmic rumbles in groups of three. These rumbles are used to help attract females to their burrows or to defend their territories against neighboring males. The rumbles recorded on the ocean floor differ from those recorded in a tank. The researchers stated that the rumbles were synchronized in a chorus similar to a group birds singing together or frogs croaking together.

I think it’s amazing that the technology we have today allows us to examine communication in the deep sea. I think the mantis shrimp give us a good insight on the origins of communication. The shrimp reinforce the theme that the meaning of a particular signal (three rumbles) depends on the context. I also believe that the shrimp may be able to give us insight on how group communication arose in birds in frogs. Perhaps there is a certain neuronal pathway to be identified responsible for promoting group synchronized communication. I think there is much more about animal communication we can learn from this tiny creature at the bottom of the sea.

Sources http://www.sciencedaily.com/releases/2011/09/110908124500.htm

Posted by Nick Gast (4)

Emperor Penguin Courtship and Breeding

Emperor Penguin Courtship and Breeding

Courtship rituals vary throughout animals. The rituals of the Emperor Penguin are extremely interesting and provide a glimpse into the different habits of animals. Breeding season for these penguins start in March and April when most travel more than 50 miles inland to look for a mate. Emperor Penguins are considered to be serial monogamous, which means they are "married" and there is an extremely high percentage that if they find their mate the following year, they will mate with the same as the previous. When the males start their mating call, they produce a sound that is recognized by their mate. If the female does not hear their call out of the thousands of male choices, then there is a likelihood that the female will find another male.

The Emperor Penguins call last about 2 seconds. Once the call is made, he will move around the crowd and keep calling until he finds a mate. Once a potential partner is in sight, they will stand in front and mirror each others posture. They will then walk around the crowd, female following the male until they face and bow to one another before copulation.

Once the female penguin lays her one egg, she will roll the egg carefully to the male and he will store it in his brood pouch which acts as an incubator. Now, the females will leave their egg and mate and return to the sea for months looking for food. Sacrificing food for a little over 100 days in order to hatch the egg. Finally, the female arrives with food for the newly hatched egg either when it has recently hatched or up to 10 days after. Now, it is the males turn to fast for another two weeks in his search for food. Since it is now late July to August, much of the ice and snow has melted and makes it a shorter journey for the male gathering food. He will then return to his mate and hatchling and share the brooding and feeding with his mate. After a couple of months after hatching, the parents stop feeding the baby penguin and he is now responsible for gathering his own food.

Emperor Penguin Breeding Video

Posted by Ryan Dulmaine (4)

http://en.wikipedia.org/wiki/Emperor_Penguin

http://www.emperor-penguin.com/emperor.html

Shake That Stinger

Dancing has always been thought of, in humans at least, as a form of entertainment. Sure, we may have some motives behind our moves, such as landing a potential "hottie", but we don't use our dancing as a solid form of communication. Bees, however, encode specific information into their unique grooves. In the "round dance", the foraging bee alternates from left to right in a narrow circular motion. The bee may repeat the dance in the same location in the hive or move on to a different one. This dance tells fellow bees that the food source is near the hive (less than 50 yards away). The longer and more intense the bee dancing, the richer the food supply is. Although the dance does not give details on which direction the food source is in, it does encode the scent of the particular flower in which it was found. Bees can use this scent to track down the flower and find the nectar.

When a food source is between 50 and 150 meters away, a bee will preform a "sickle dance". This particular dance is described more as crescent shaped, and acts as a transitional dance between the round dance and the waggle dance.

The "waggle dance" is used when the food source that is found is more than 150 yards away. In starting this dance, the be runs straightforward, then makes a semicircle as it returns to the starting point. It jets straightforward once again in the same diction, then turns in a semicircle in the opposite direction, completing a figure eight shape. While the been is running straight, it wags it body from side to side. The run is vital, as its direction indicates the direction in which the nectar relative to the sun. Since the bees rely on the sun for directional information, the bee's dance changes depending on the time of day as well as the time of year. The distance of the food source is also accounted for in this dance by the rate in which the bee "semicircles" as well as the duration of its buzzing.

Bees prove to be fascinatingly smart insects, as their entire life is well structured and colonized, even down to their dance steps. It is interesting that they are able to deduce the direction of food in relation to the sun; the ability to distinguish such angles is remarkable for such a tiny creature! These visual signals seem to allow the bees to communicate in their environment with much more ease than they would have vocally, as I can imagine the hive can get quite noisy with all the busyworkers buzzing around!

Here is a video of a bee preforming the "waggle dance"

http://www.youtube.com/watch?v=-7ijI-g4jHg

Sources:

1) http://www.cals.ncsu.edu/entomology/apiculture/pdfs/1.11%20copy.pdf

2) http://www.pbs.org/wgbh/nova/bees/dancesdire.html

Posted by: Sara Corey (4)

The Detectives Break Out of the Slammer

THE DETECTIVES BREAK OUT!

For those of you that haven’t read my first post, I’ve been blogging about my contraband pets. I have two male zebra finches whose names are Sherlock and Watson. They’re collectively referred to as “the detectives.” I’ve been able to spend a lot more time with the detectives since my last post, and have picked up on a few very interesting signals that apply to a few equally interesting behaviors.

For about 6 weeks I’ve been conditioning the detectives to know their cage is “home.” I made sure to avoid making eye contact, sudden movements, and loud noises around it. The detectives got all their food, water, and treats in the cage, and were therefore able to feel relatively safe within it. Thus, I hypothesized, if I were to let them out for free-flying time in the room, they would eventually both return to the comfort and safety of “home.” Early last week I tested this hypothesis, and every day since then, I now have two birds flying cheerfully through my room and pooping on all my stuff. It’s a wonderful sight, minus the pooping. More importantly, though, the free-flying time allows me to observe new and old behaviors alike up-close without making the detectives feel as constricted as they would in the cage. The signals I’ll be talking about today pertain to the male finch mating ritual.

I’ll preface the description by reiterating that Sherlock and Watson are both male zebras. They’d been humping each other relatively often before free-flying time began, but the behavior seems to have changed now that they have more room to execute their ritual. I have not yet read up on zebra finch mating displays, so what follows is purely observation, which I back up with factual sources only after having typed the observations.

I chose to talk about the detectives’ attempted mating habits mostly because of how ritualistic the behavior is- it’s different from dog behavior, where a male dog will hump anything in sight “just because.” Rather, it’s a complicated ritual that’s preceded by both vocal and visual signals, and both of the detectives seem very receptive to the process as a whole.

When still in the cage, the humping was preceded only by a very unique mating call. While most of the detectives’ calls are whistles or shallow caws, the mating call is a distinct hum. It sounds like a person forcing a tiny bit of air through tightly closed lips. Before given free-flying space, the detectives would both make this call and one would mount the other. A few days ago, I caught them doing a much more elaborate ritual during their free-flying time. They made the same mating call, but then stopped, and chattered their beaks open and shut incredibly quickly to create a series of snapping sounds. Continuing to do this, they would then wag their long tail feathers up and down so quickly that the tail produces a sound. In this part of the ritual, one male will stand upright to lift his head and lower his tail, while the other lowers his breast to his feet and raises the tail, taking a submissive position. They would then resume the vocal mating call, and the one that’s standing up will mount the one in the submissive position. They don’t seem to have clearly assigned roles, and the “submissive” bird will change each time.

After doing some research on zebra finch mating, I failed to come up with good sources describing the process. Wikipedia does nod at the hum I mentioned, stating that finches use a distinct high-pitched whine in mating calls. I did, however, find many articles on male-male pair bonding in zebra finches. One of them, from DiscoveryNews, even notes some behaviors that I observed my finches doing but didn’t recognize as couple-behaviors. I often catch the detectives preening each other and nuzzling beaks, but don’t think twice about it. According to DiscoveryNews, these are signs of affection, and could mean Sherlock and Watson have entered a “bros for life” relationship status.

I’ve learned a lot through observing my finches. I find the non-vocal signals like beak-chattering and tail- and wing- wagging especially intriguing. More on the misadventures of the detectives next time! Thanks for tuning in! Here are some pictures of the detectives in exchange!

Posted By Jonathan Flash (4)


Sources:
http://news.discovery.com/animals/zebra-finch-bro-mance-trumps-mating-110817.html

http://en.wikipedia.org/wiki/Zebra_Finch#Song_and_other_vocalizations

http://blogs.smithsonianmag.com/science/2011/08/same-sex-finch-couples-form-strong-bonds/

Week 4: The Dolphins Have It

Whenever I mention one of my favorite animals is a killer whale, they respond "Oh the whales at Sea World?" Little do they know that killer whales are actually dolphins, also known as orcas. They are the largest species of dolphin and are considered the top predator of the ocean. Killer whales got their name from the food they hunt; right whales. Sailors were helped by killer whales back when whaling was legal. If you ever want to read a good book, read The Killers of Eden. The book highlights how fishermen, with the aid of killer whales, killed right whales and were able to maintain a livelihood. The sailors would then leave the tongue for the killer whales to eat as a thanks for helping them.

Anyways, killer whales are the top predator of the sea because they live in large family groups called pods. The pods are based off of a matriarchal leader, usually the oldest female (just like elephants). The pods consist of both males and females, basically one large family. To keep the pod as one, they use a complex system of whistles, echolocation clicks, pulsed calls, low-frequency pops, and jaw claps. Without the diversity of sounds they produce killer whales would not be able to communicate their desires in an efficient way.

Killer whales also teach their young how to hunt with their communication skills. An example would be seal hunting. Killer whales use clicks and whistles to indicate where the seals are on the beach. They then ride the tide in and capture the unsuspecting seals. It is fascinating the complexity behind their hunting. They have also been known to push right whales and their calves towards open water where they drown the calves. Killer whales also eat sharks, great whites in particular; this is why they are dubbed the top predator of the sea.

They are my favorite animal because of the songs and sounds they produce. I get chills whenever I hear them. Not sure how you feel, but one of my goals in life are to see killer whales in the wild and not performing tricks for entertainment. I want to kayak along side a pod. Sounds dangerous because you do not know when they will surface, but that is a risk I am willing to take. I have heard from those that have kayaked alongside a pod that the orcas look at you, or more like look through to your soul when they go under your boat. Their songs can be felt through the boat and heard from the surface. I would love to have that opportunity. Wouldn't you?

Posted by: Em Arsenault (4)

MATES FOR LIFE

When I was in California this summer I visited the Monterey Bay Aquarium and I remember seeing the seahorse exhibit. There was one type of seahorse that would stay with a partner for life and often did dances for each other and held tails for periods of the day. I found it very interesting because many people think animals only mate to reproduce and do not always stay together, but as we saw with the gulls in class many animals often find a partner and stay with one another their whole life.

I decided to do more research in the topic and found that there are many species that may show more faithfulness than humans. Swans are another bird species that often mate for life and will make bonds that last year round for many years, although they may “divorce” if there is nesting failure. French angelfish are another species that form a lasting bond. They will live, travel, and hunt in pairs until one dies. Similar to the gulls video, angelfish will also work vigorously to defend their territory from other neighboring pairs.

Albatrosses are another species known for their loyalty. They often fly extensive distances away from each other, but they always return to the same partner when it is time to breed. The bond between the two is formed over several years and will last a lifetime. The females tend to stick close to the breeding habitat, but males often spend a year or two at sea flying around the world.

Although rodents are not typically known for their monogamy there is one species, the prairie vole, who will huddle and groom each other as well as share nest and pup-raising responsibilities and stay together their whole life.

Then, of course, there are the turtle doves, which have been an emblem of love for quite awhile. Other species include wolves, schistosoma mansoni worms, bald eagles, gibbons, black vultures, coyotes, and beavers. It might prove interesting for humans to study the monogamy of these species and why they stay together for life when so many other species do not.

Posted by Caitlin Descovich O'Hare (4)

Source: http://www.mnn.com/earth-matters/animals/photos/11-animals-that-mate-for-life/old-faithful

COTE (Common Tern) Chicks Beg Parent for Food

I spent this past summer living on White Island in the Isles of Shoals off the coast of NH. I was an intern working for the Tern Restoration Project, which aims to restore terns back to their historical habitat.

The island we lived on, White Island, doesn't have many nesting birds on it, but connected to it at low tide is Seavey Island, which supports the majority of our tern populations.

The three species of Terns living on Seavey island are Common Terns, Roseate Terns, and Arctic Terns. The Common Terns were by far the most numerous, with a nesting population of 2000+ pairs; followed by about 40 pairs of nesting Roseates and 4 pairs of nesting Arctics. Typically, each nest will have 3 eggs, most of which will hatch. Needless to say, the island, which is very small, is also very crowded, and life is extremely difficult for these birds and their young. Not only do the tern eggs/young chicks have many predators they must survive, they must also survive the battle for food/nest space/warmth and attention from their parents. Very often, tern chicks will be attacked and killed by the adult birds from a neighboring nest, by other chicks, or even by their own parents. Also, whichever chick gets to the fish first will get fed the most, and have the best chance of survival. This is key: many, many chicks die from starvation because their parents are only able to catch enough fish to feed one or two out of the three.

Attached is a video I took from an observation blind of two Common Tern chicks. They are probably a week or so old, and they are begging their parent for food. They do this by running up to one of their parents (which is standing on the ground near them) with their beaks open. Also, they are constantly on the watch for their second parent, who is out catching fish. Whenever they catch sight of an adult who they think is their parent returning with a fish, they scramble in the direction of that bird and start begging for food.

Most likely, only one of these two chicks survived long enough to fledge the nest.

See below for the video.

Also, this is a picture of the two islands: the island on the left with the lighthouse and the house is White Island, and the island to the right is Seavey island.

Posted By Johanna Brophy (group A, blog post 2, week 4)

Communication in Orca whales

A couple of blogs posted in the past few weeks relating to whales reminded me of something I saw on Animal Planet about the hunting behavior of Orca whales, so I decided to do some research to see what has actually been learned about these fierce predators. As you may know, Orca whales are not actually whales at all, but are in the order Delphinidae, making them the largest of the dolphin family. They form matrilineal groups called pods, which can then be grouped into larger clans based on genetic and behavioral differences. It is also important to note that there are 3 distinct population types; the transient, residential, and offshore populations. Residential populations, while still nomadic, have a smaller home range than the other two population types, and also tend to have larger pod sizes, around 50 individuals. Transient populations are usually only made up of 6 to 8 individuals, and do not seem to have the same strong family bonds displayed by the residential populations, likely because of the amount of movement to follow food displayed in these individuals. Not much is known about the offshore populations, except that they are genetically distinct from the other two populations, and (you guessed it) tend to stay close to the shore.

Orca whales are also known to have 3 types of calls: whistles, pulses, and clicks (used for echolocation). As it turns out, all Orca whales, much like species of birds we have talked about in class, are known to have pod-specific dialects, likely formed due to the high level of social interactions displayed between members of the same pod in this species. Dr. John Ford was able to group pods together based on similarities in their dialects, to form larger clans.

It has been observed that the various calls used by these whales are partly innate and partly learned. Apparently, different pods with genetically related individuals have more similar calls than those without genetically related individuals, suggesting that it is partly innate. However, according to MERSEA (Marine Education and Research of South East Alaska, 2009), mothers teaching their calls to their young has been observed.

The high level of social interaction displayed by these mammals has also led to the development of a quite impressive skill of coordinated hunting; although, what has really surprised me is the incredible variety in communication and hunting strategies displayed by this species.

I found an article from BBC news that focuses on the transient populations of Orcas, which have been observed during bouts of hunting as actually being silent until they make their kill, likely because they mostly hunt marine mammals that could hear them communicating underwater. In this article, researchers hypothesize that these small groups rehearse a simple hunting strategy which they can then employ without having to make sound. Here's a link to that article: http://news.bbc.co.uk/earth/hi/earth_news/newsid_9409000/9409694.stm

Here's a link to the hunt that I was originally thinking of; a small pod led by the head matriarch of the group, using communication & cooperation to catch the seal stranded on an ice flow: http://www.youtube.com/watch?v=p3xmqbNsRSk

Here's a link to another interesting clip I found, and I was really surprised by the difference between this behavior and the behavior of the previous clip.. I'm not sure if it is because this is two males (as opposed to the matrilineal family group of the first clip) or if maybe these are clips from two different populations, causing them to employ different hunting behaviors. http://www.youtube.com/watch?v=DWsN63PRCW8

Either way, Orca whales seem to be highly intelligent, and I think there is still a lot to be learned from these marine mammals and their methods of communication and hunting, despite their bad reputation as ruthless killers.

References:

Dolphins-World.com. (2009). Killer Whale Communication. Killer Whales. Retrieved from: http://orca.dolphins-world.com/killer-whale-communication.html

MERSEA (Marine Education and Research of South East Alaska). (2000). ORCA - The Killer Whale: King of the Sea. Retrieved from: http://www.mersea.com/Orca%20Info.htm

OrcaLab. (2011). OrcaLab. Orca Communication. Retrieved from: http://www.orcalab.org/about-orcas/information/communication/index.htm

Victoria Gill. (March 2011). BBC News. Killer whales hunt in silent "stealth mode". Retrieved from: http://news.bbc.co.uk/earth/hi/earth_news/newsid_9409000/9409694.stm

Posted by Brianna Eddy (4)

Is your Horse Afraid of the Dark?

Is your Horse Afraid of the Dark?

In horse riding I know from personal experience that the most dangerous party of horse riding can open be horse’s flight reaction when they are scared. When riding at night a shadowed or a quick motion can set your horse bolting to the other side of the ring while you hang on for dear life. In Uta Von Borstel’s paper, “ Fear Reactions in trained and untrained horses from dressage and show-jumping breeding lines” mentions that as much as 27% of all horse related accidents are due to the horses fear response. Heitkamp et al. (1998) discovered that the common belief that dressage horses are more nervous than show jumpers is true. In the study they found that the injury rate of show jumpers and dressage riders were the same, but the showjumpers’ accidents were more sever. This is still surprising because showjumping involves more risk due to the nature of jumping high objects.

Show jumping horses appear to be more calm because they have been breed to be responsive to the riders’ cues, fast and good at jumping, where as, dressage horses have been breed to be very sensitive to the riders cues. The selection for these characteristics could have caused physiological changes in the horses other genes causing it to be more fearful. Another possibility is that the training that the show jumper receives decreases the sensitivity to possible fear inducing objects. One direction, I would love to look at would be how police horses, bullfight horses and cross country jumpers fair in fear response tests.

References / Link to Article:

http://apps.webofknowledge.com/full_record.do?product=WOS&search_mode=Refine&qid=2&SID=1CeE69DcE3k986ojbai&page=1&doc=6

Heitkamp et al., 1998 H.C. Heitkamp, T. Horstmann and D. Hillgeris, Reitverletzungen und Verletzungen beim Umgang mit Pferden bei erfahrenen Reitern. Unfallchirurg, 101 (1998), pp. 122–128.

By Caroline Adams (4)