When I think about communication between two species I either think about visual cues or vocal noises. There are a wide variety of other communication methods that animals as well as humans use. One type of communication method are chemical signals. Nearctic River Otters are an example of an animal that uses chemical signals. The otters deposit feces, scat jellies, urine, and dark colored anal gland secretion at latrine sites. Depositing these odor markings is physically costly, therefore there must be an adaptive reason as to why they do it.
Scientists ran an experiment to test the role of the marks. The scientists found five active latrine sites. They then covered the sites with a new layer of sand. They used the sand to see how many new tracks were made and then intuitively reasoned how many otters visited the site. After covering the sites with sand the scientists removed the old scat from the territory and replaced the sites either with local or non local new scat. They did the study for seventy days.
The scientists found that the sites replaced with scat from non local otters were visited far more. The scat on these sites were also moved around and often replaced with new scat. Urine markings in these areas also increased. This experiment showed that the river otters can tell the difference between local and non local markings. This experiment backs up the notion that the otters use these markings as territorial borders within different social groups. The otters use the scat to determine if the territory they are in belongs to other members of their social group.
Charles Carville
So glad that we rely more on tactile, auditory, and visual signals rather than use our sense of smell. Were there only 5 sites in the area, or did the researchers just use 5 sites? Is there a finite number of sites an otter uses normally or does it just depend on their territory size?
ReplyDeletePosted by Daniel Solomon
This sounds similar to the beavers. I wonder if this communication strategy evolved from a common ancestor or evolved independently.
ReplyDelete-Alex Sprague
Did the researchers find any more information to suggest the latrines being used for purposes other than territorial reasons? Could they be used during the mating season to attract mates as relocation devices for members of the same social group? I love otters and learning about them. This was really interesting! Thanks!
ReplyDeletePosted by Shyla Morsbach
This sounds a lot of like what we learned in class. I wonder if there were any chemical analysis of the differences between the the different deposits, and whether theese differences relate to group size, strength of individuals, or ability of acquiring resources?
ReplyDelete-Himanshu
There were more than 5 sites in the area but the researchers chose the most commonly used by the otters. The number of sites depends on the territory size combined with the number of neighbors the group has. In this site there were a lot of otters because it was a reservation.The article I read was focused mainly on territorial boundaries so they didn't talk about other uses for the sites.
ReplyDeleteCharles Carville