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.
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)
It's interesting to see how physically the sight of another creature can dictate the type of vocal response by an animal. It reminds of early cartoons when you may have a protagonist acting like a big shot but then when they see someone bigger and stronger they stutter and voice goes high. That same intimidation factor that the bigger human being is effective for dogs as well. I wonder what would happen if you showed pictures of animals larger and smaller than the dog and see if that illicit any response.
ReplyDeletePosted By Jobin Oommen
I look forward to learning more about communication in mammals in class and I feel like this article is a perfect example. Its really interesting that these growls are indicators of size and leads me to question if they are always honest indicators or if they can be manipulated to make a dog seem bigger than he really is. I am assuming that in this case a growl would be limited by the animals physiology so a dog is only capable of a certain level of growl that would be an honest indicator of its size. Certainly a chihuahua cannot sound like a great dane.
ReplyDeleteAlso I would be interested to know what else can be indicated by a growl. Is a females growl different from a males growth? Can age be deciphered from a growl?
Posted by Suzanne Sullivan
This reminds me how different human evolution has been from that of animals like dogs. I don't know much about human vocal evolution, but I do know that it is not always a great indicator of size. I have met thin, tall women with very low voices and big, bulky guys with higher voices. It amazes me how much our evolution has not focused on these cues for survival. We would never need to identify how big someone was in order to see if we could take them in a fight to survive (at least not on the regular, I hope). Dogs have these abilities to continue reproduction and survival, basically. We are so far from these basic needs in the present that natural selection seems to have ignored them altogether. What makes us so special?!
ReplyDeletePosted by Chelsea Van Thof
This is a a pretty cool phenomenon which is certainly not just found in birds and dogs. I think that in generally many of the aggressive signals are used to indicate size and fitness to other males in order to win a fight over without having to physically fight. The ability of dogs to raise the fur on their back makes them look larger and thus more likely to win a fight.
ReplyDeleteInterspecies communication is also really interesting. How two different species still retain the ability to understand one another is vital to their survival. However, some dogs have been over breed that they no longer understand some of the simple dog cues.
Last Post by Caroline Adams
ReplyDeleteThis is a very interesting expansion on our class topic. I guess a growl would say a lot about the dog's size, but we do not often think about this when we walk our dogs. Did the study look into small dogs that still act aggressively to larger dog breeds? I know that once when I walked my grandmother's mixed breed dog, who is quite large in size, a neighbor's dog that was a little larger than a chihuahua came running over growling and did not back down. Do you think that there could possibly also be personality that changes their reaction?
ReplyDeletePosted by Caitlin O'Hare
I think that Caitlin makes a great point here. I am a dog lover myself and own an Alaskan husky. As you might guess, he is a rather large dog and is very territorial. Almost everyday, one of my neighbors walks her little schnauzer past my house, and he never fails to bark at my dog first. This makes me wonder why some dogs seem to back down from larger dogs that could be an obvious threat to their survival, and others don't. This could be a variable that the researchers did not consider in the first part of their experiment.
ReplyDeletePosted by Sara Corey
What about hormone levels? Alpha animals seem to illicit different responses than other dogs of their breed. Is it just the size, or perceived size, of the dog in the call, or is there some more complex underlying information? Do dominance levels shift with context (i.e. a lack of an alpha causes another animal to shift to that role) and if so, do barks follow suit?
ReplyDeleteLast post by Joseph Needleman
ReplyDeleteThis phenomenon actually makes a lot of sense. Generally the bigger the animal, the deeper the voice. One purpose of barking and growling and aggressive displays is to communicate fighting skill and size up your opponent. If the subject dog hears a dog he thinks is smaller than himself, he will become confident and aggressive, but if he thinks the other dog is larger and might beat him, he will shrink and concede.
ReplyDelete-Rhys Ursuliak
@Suzanne - The studies did not specifically mention differences in growls of females and males. But in the results section, it appears that males are more likely to respond than female dogs, so there very well might be a difference in the growls of males and females. The studies also did not mention if age could be deciphered from growls.
ReplyDelete@Joseph - The studies did not look into hormone levels, but that definitely would be something interesting to look into. Also, the dogs studied were domesticated dogs, so I'm not sure how different responses of alpha dogs would be than other dogs of their breed.
Posted by James Lin
This is a very interesting article that dogs could determine size of other dogs based on auditory recordings of growls. I would imagine that the dogs were able to determine this by the pitch of the dog barking? It seems smaller dogs create a higher pitch where bigger dogs would create a lower pitch and maybe this could be what the dogs recognized. It is also equally amazing they could match the growls with the pictures.
ReplyDeleteposted by: Andrew Ryan