Gorilla Politics?

Imagine being in a notorious biker gang, led by one ultimate badass biker, living the independent biker lifestyle. Now imagine being a gorilla that leads a pack of 46 other gorillas, providing protection and guidance...now that's badass. A 31 year-old silverback gorilla named Cantsbee has led his group for 15 years and is now nearing the end of his reign as leader. Cantsbee is the leader of the largest pack of gorillas in the world, his pack alone represents 7% of the remaining mountain gorillas in the world! Cantsbee is now starting to share his power with another younger silverback named Gicurasi, who is 15 years-old and is in his prime.

Gorillas spend their lives hoping one day to be able to be a leader of a group. With leadership comes access to females, but they are also in charge of protecting the group. The aging Cantsbee has been allowing Gicurasi to split up and lead smaller packs on day-trips along with sexual encounters with female gorillas. In the end of the day, Gicurasi would always return to the main group.

It's amazing to hear about how these gorillas are capable of organizing these hierarchical-like groups to drive the well-being and survival of their species. It also seems like the tranfer of power is fairly accepted and understood, as compared to humans where we try to retain power for as long as we can. This article really made we wonder about the level of communication between these gorillas. Keeping a pack together for 15 years really tells shows how much these gorillas rely on the leader and on each other.

link to the article


Kevin Tse

NEW SPECIES FOUND IN MADAGASCAR

Imagine walking through the wetlands of Madagascar and accidentally happening upon an entirely new species of animal. I came upon this article on BBC.com and was intrigued by the notion of a brand new creature being discovered in 2010. Upon further reading I learned that this new species, called Durrell's vontsira (Salanoia durrelli), is a mongoose like animal that most likely feeds on fish or small mammals. That fact titillates scientists because that is a very unusual diet for a mongoose, which is one of the reasons they know it is a new species. The scientists also compared this creature to the closest relative they could find, the brown-tailed vontsira.

"In addition, we found obvious differences in the structure of the skull and teeth... the size and shape of the pads on the paws clearly distinguished this animal from the brown-tailed vontsira, which is a forest-dwelling animal found in eastern Madagascar. It was indeed a distinct new species and the specimen we have in the museum is now recognised as the holotype (the specimen from which the species takes its name) so it is available to scientists for research in the future."

Madagascar is a hot spot for new species. Durrell's vontsira is the fourth new species found in the area since 2006. Unfortunately, it like many other of the new species, has been classified as endangered. It seems the wetlands that it inhabits has been greatly affected by pollution. However, this is most definitely a story worth following up on.

If you want to learn more, check out these sites:
The BBC article
Durrell's Wildlife Conservation Site
IUCN Red List of Threatened Species

Posted by: Vuzmal (Meesha) Sharma

Laughing Rats and Cackling Hyenas

Humans laugh for all kinds of reasons. When someone tells a funny joke or when we are experiencing the emotions of joy, surprise, amusement, nervousness, or fear we may laugh. It turns out that animals also produce laughter, although for different reasons. Two articles I read explored the "chirp of joy" made by juvenile rats when they are tickled, and the laughter-like vocalization of the spotted hyena.

A study on rats found that when juveniles were tickled they produce 50kHz ultrasonic "chirps of joy". Researcher Jaak Panksepp found that the young rats were most ticklish at the nape, which is the focus of pinning and other play behavior between rats. The most "ticklish" individuals- the ones the emitted the most chirps- were also found to be the most naturally playful. Tickling also promoted bonding between rats and people, and between rats. Panksepp suggests that this response to tickling in rats is akin to the response to tickling in human infants.

Spotted Hyenas (crocuta crocuta) do not laugh because of joy or amusement, but as a way to express their social standing- according to researchers Mathevon et al. The characteristic cackling sound is made most frequently during a social conflict or a feeding session. The researchers determined that each hyena produces a unique "laugh" that encodes information about their age and rank. Hyenas with high-pitched, variable cackles were lower-ranking individuals, and hyenas with lower, monotone cackles were higher-ranking.

I think what these two articles have in common is that they show how "laughter" (chirps or laughter-like vocalizations) in the animal kingdom is distinct from the "sense of humor" in humans. If anyone has an example of animals with a sense of humor that would be really interesting!

If you are interested in reading the articles they can be found here: http://scientificamerican.com/article.cfm?id=laughing-rats-and-ticklish-gorillas-2010-08-03
http://www.livescience.com/animals/090905-hyena-giggle.html

Posted by Alex Sprague (3)

Edit:

Thank you all for the comments!

I didn’t know that licking in mice decreases the expression of a stress gene. That is really interesting and it seems like the same thing could apply to tickling in rats. In some way the tickling might change expression of a gene, or just increase the levels of certain hormones in the rat which make it friendlier and happier. The article only talked about the results of tickling, but didn’t provide a mechanism for the behavior.

Dog Growls Contain Specific Information

Everyone who's been growled at by a dog knows the sound of this vocal communication. In a non playful way, we know to back off. When we're playing with dogs however, we find the growl to be something totally different.

Dogs are also able to distinguish upon these different growls among different breeds. In the first study where 20 breeds of dogs had their growls recorded and analyzed for differences, there was a significant difference between playful and non-playful growls but not between non-playful growls when a dog defends a piece of food and a growl of a threat approaching.

In a second study, a fresh, irresistible cooked piece of meat was placed in a bowl. 41 adult pet dogs of different breeds approached the piece of food only to have a recorded sound from the previous played back from a hidden speaker. The dogs only reacted and jumped to the recording of a "defending a piece of food" growl and not the stranger threat growl that was analyzed and found no difference between the two.

This finding suggested that there are even deeper things dogs communicate to each other with and lots more remain unknown in this particular field of dog communication.

Source: http://news.discovery.com/animals/dog-growl-communication.html

Posted by Vince Tieu

Amber Kapchinske "attack frequency based on prey group size"

Attack frequency, attack success and choice of prey group size for two predators with contrasting hunting strategies
Will Cresswella, , and John L. Quinnb, 1

The size of a flock of redshanks affected the method of hunting used by two species of raptors. Predators have various modes of hunting that are determined by the response of the prey. Sometimes it is more appropriate for the prey to be chased down before it is captured or killed. Other times it is more appropriate for the prey to be caught by surprise. In this study the size of the redshank flock determines which method the raptors will use in order to obtain the most successful attacks.

If the flock size of redshanks increased, the attack success of peregrines declined when using the surprise –attack and the nonsurprise-attack. The sparrowhawks attack success declined when using the surprise-attack only. The sparrowhawks attack success did not decline when it used non-surprise attacks because it only used this mode of predation when it was already spotted by the redshank. The Peregrine falcon and the sparrowhawk varied in hunting style only when a flock of redshanks was large. The sparrowhawk hunted mostly from cover and the Peregrine falcon preferred to attack from the open where the prey could see him. When the prey lived in a smaller flock, they relied on vigelence to protect against predators. When the redshanks lived in a larger flock, they relied more on the confusion effect.

When the surprise attack mode of predation was used, the success of attacks involving both species of raptor decreased as the population of the prey increased. This leads us to the conclusion that having a greater number of redshanks in a flock will ensure the highest rate of survival for the flock.

Check out this video of a peregrine falcon attacking a grouse!

http://www.arkive.org/peregrine-falcon/falco-peregrinus/video-08c.html

Panda Communication

Panda’s have a large vocabulary of grunts, moans, chirps, honks, growls, etc. but one study focused on the “bleat”calls they using during the mating season and found some interesting results as to what information the pandas were communicating to each other.
Most men might be self conscious about their size and most women try to hide their age. Panda’s, on the other hand, unknowingly and unwillingly reveal this information to the opposite sex. A study done on nine female and nine male pandas, ages 6 to 21 revealed that “bleats” used during the breeding season, send out a lot of information about an individual. First, it was found that there are definite masculine and feminine differences between the voices of males and females. Second, it was discovered that the bleats could reveal information about the size and bodyweight of a male. This is beneficial to females trying to choose a strong and healthy mate and also beneficial to males who can avoid a confrontation with a larger and more dangerous male. Third, if was found that females voices change as they age which allows males to gain knowledge of the approximate age of the female. Males would prefer an older female who has experience giving birth and raising young so this information is very important for the males to obtain if they wish to produce successful offspring.



Source:
http://dsc.discovery.com/news/2009/09/14/panda-calls.html

By Meghan Nichols

Bat Communication Differs Individually

After working on RAVEN and discovering that individual birds within a species have distinct song types, I was curious to find out if bats have distinct calls between individuals.

In this article,15,103 calls from 5 pairs of adult male little brown bats were studied using two forms of analysis: Discriminant function analysis (DFA) and multivariate analysis of variance(MANOVA). DFA, I learned, defines whether or not calls can identify the bat individually.MANOVA defines whether or not the calls are the same. They studied, much like our lab, the minimum and maximum frequencies, and the call duration of two calls the bats made. These calls included the broadband noiseburst(BNB)and the steep-FM (StFM).

Thirty sample calls, from each song type, per bat were analyzed. Data showed that all three measurements being used to analyze the calls could differentiate StFM calls of specific individual little brown bats. BNB calls could be differentiated between individuals using duration and maximum frequency measurements.

The conclusion was that yes, there are distinct differences between the same type of call per male little brown bat. What is still to be learned, is whether or not these differences are recognized between individuals within the species and social group they're in. Do their behaviors between one another show a response to the differences in their calls?

Posted by Shyla Morsbach (2)