Popular version of paper 4pABb2, presented at the th 164th ASA Meeting, Kansas City, Missouri.
To explore the feasibility of using information in the calls of terrestrial mammals to census populations, we looked for individual, age-class, and sex-related information in the alarm calls of Belding’s ground squirrels (Spermophilus beldingi). These ground squirrels live in colonies of related females and their dependent offspring, with males occupying territories on the colony’s edge (Mateo, 2003). While males do produce alarm calls, most are given by adult females in an attempt to warn their offspring of danger. Whistles are given in response to aerial predators such as hawks, single chirps are given to slow-moving terrestrial predators such as humans, or to remind others to remain vigilant, such as when a predator has recently left the area (Mateo, 2003; Owings et al., 1986) (A Belding’s ground squirrel chirp). Trills are a series of notes that are typically produced in response to more dangerous terrestrial predators such as bobcats and coyotes (Sherman, 1980) (A Belding’s ground squirrel trill).
Belding's ground squirrel chirp
Belding's ground squirrel trill
Our previous work with golden-mantled ground squirrels (Spermophilus lateralis) suggested that these vocal similarities may reflect close kin relationships (Hooper, 2010). To investigate whether this was true for Belding’s ground squirrels, we recorded alarm calls and collected tissue samples from adult and juvenile Belding’s ground squirrels at multiple distinct locations in the Sierra Nevada Mountains and Modoc plateau. Alarm calls were measured as before, yielding an index of vocal similarity. We extracted DNA from the tissue samples, and calculated a measure of genetic relatedness between individuals using GenePop software. Vocal similarity and genetic relatedness were compared using a Mantel test, and the results confirmed that related squirrels had more similar voices than unrelated squirrels.
Our results indicate that vocalizations such as alarm calls have the potential to provide additional information about mammalian populations to wildlife managers, including census data. It is also possible that the level of vocal similarity in a population provide information about the level of inbreeding, which could indicate whether a population is becoming genetically isolated and therefore vulnerable to the effects of inbreeding depression.
Blumstein, D. T., and Munos, O. 2005. Individual, age and sex-specific information contained in yellow-bellied marmot alarm calls. Animal Behaviour 69, 353-361.
Bradbury, J. and Vehrencamp, S. 1998. Principles of Animal Communication. Sinaur Associates: Massachusetts.
Hartwig, S., 2005. Individual acoustic identification as a non-invasive conservation tool: an approach to the conservation of the African wild dog Lycaon pictus (Temminck, 1820). Bioacoustics 15, 35-50.
Hooper, S. L. 2010. Impacts and applications: Developing a bioacoustic tool for mammals and measuring the effects of highway noise on a mammalian communication system, using ground squirrels as a model. Ph.D. thesis. University of California, Davis, Davis, CA.
Mateo, J. 2003. Kin recognition in ground squirrels and other rodents. Journal of Mammalogy 84, 1163-1181.
McGregor, P. K. and Peake, T. M., 1998. The role of individual identification in conservation biology. In: Caro, T. M. (Ed.), Behavioral Ecology and Conservation Biology, Oxford University Press, New York. pp. 31-55.
Owings, D. H., Hennessy, D. F., Leger, D. W., and Gladney, A. B. 1986. Different functions of “alarm” calling for different time scales: a preliminary report. Behavior 99, 101-116.
Sherman, P. W. 1980. The limits of ground squirrel nepotism. In: Barlow, G.W. and Silverberg, J. (Eds.), Sociobiology: Beyond Nature/nurture? Westview Press, Boulder, Colorado, pp. 505-544.
Slobodchikoff, C. and Placer, J. 2006. Acoustic structures in the alarm calls of Gunnison’s prairie dogs. The Journal of the Acoustical Society of America 119, 3153-3160.