Wildlife Research Wildlife Research Society
Ecology, management and conservation in natural and modified habitats
RESEARCH ARTICLE

Uncovering the secret lives of sewer rats (Rattus norvegicus): movements, distribution and population dynamics revealed by a capture–mark–recapture study

Ann-Charlotte Heiberg A , Vincent Sluydts B and Herwig Leirs A B C
+ Author Affliations
- Author Affliations

A Danish Pest Infestation Laboratory, Dept. of Integrated Pest Management, Aarhus University, Forsøgsvej 1, DK-4200 Slagelse, Denmark.

B Evolutionary Ecology Group, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium.

C Corresponding author. Email: herwig.leirs@ua.ac.be

Wildlife Research 39(3) 202-219 https://doi.org/10.1071/WR11149
Submitted: 12 August 2011  Accepted: 11 January 2012   Published: 23 April 2012

Abstract

Context.: In many parts of the world, brown rats have colonised sewer systems and the rat populations in sewers are often thought to be a source of problems with rats on the surface. The management of sewer rat populations is usually performed with little, if any, knowledge of the dynamics and behaviour of these populations.

Aims.: The study aimed to uncover the population dynamics, movements and distribution of rats in populations living in sewers.

Methods.: We studied rats in a capture–mark–recapture study in two adjacent but separate sewer systems in suburban Copenhagen, Denmark, covering a surface area of 30 Ha. Multiple-capture live traps were placed in manholes in public sewers; animals were marked individually and data were collected every fourth week for a period of almost 3 years.

Key results.: In total, 332 individual rats were trapped. Approximately one-third were only caught once, half of these were juveniles. The median time an individual was present in the sewers was 4 months with maxima up to 22 months. Abundance ranged from 2 to 44 animals per sewer system and the dynamics showed no regular fluctuations. Rats were distributed throughout the study area, regardless of sewer dimensions. Juvenile rats were captured more in the smaller and drier sewer sections. Activity areas of rats of both sexes overlapped partially, and observations of bite wounds were rare, suggesting a high degree of tolerance. The average maximal distance covered by rats was ~200 m for both sexes. Day-to-day movements took place over shorter distances. There were no movements of rats between sewer systems and no sewer rats were observed to be active on the surface. The rat populations seemed to be substructured in smaller groups.

Conclusions.: Sewer rat populations vary irregularly in abundance. Pipe dimensions are not important for the presence of rats but breeding seems concentrated in smaller and drier pipes. Most individuals are resident and live in small groups that are active in a limited area only, but still there is a fair group of dispersing rats.

Implications.: Sewer rat management should be spread out spatially in a sewer system since most rats move over short areas only. Recolonisation by dispersing rats must be taken into account if sewer systems are connected. It is likely that targeting smaller and drier pipes will affect reproductive success.


References

Abdelkrim, J., Pascal, M., Calmet, C., and Samadi, S. (2005). Importance of assessing population genetic structure before eradication of invasive species: examples from insular Norway rat populations. Conservation Biology 19, 1509–1518.
Importance of assessing population genetic structure before eradication of invasive species: examples from insular Norway rat populations.CrossRef | open url image1

Barnett, S. A., and Bathard, A. H. (1953). Population dynamics of sewer rats. The Journal of Hygiene 51, 483–491.
Population dynamics of sewer rats.CrossRef | 1:STN:280:DyaG2c%2FjvFWisA%3D%3D&md5=96045bb2f91ec4b125f46fa52f939592CAS | open url image1

Bentley, E. W., Bathard, A. H., and Riley, J. D. (1959). The rates of recovery of sewer rat populations after poisoning. The Journal of Hygiene 57, 291–298.
The rates of recovery of sewer rat populations after poisoning.CrossRef | 1:STN:280:DyaF3c7hvFCjug%3D%3D&md5=c1dae6a0b4b4b9d3d0a85f340380f6f9CAS | open url image1

Bishop, J. A., and Hartley, D. J. (1976). The size and age structure of rural populations of rattus norvegicus containing individuals resistant to the anticoagulant poison warfarin. Journal of Animal Ecology 45, 623–646.
The size and age structure of rural populations of rattus norvegicus containing individuals resistant to the anticoagulant poison warfarin.CrossRef | open url image1

Calhoun, J. B. (1962). The ecology and sociology of the Norway rat. Public Health Service Publication No. 1008. U.S. Department of Health, Education and Welfare.

Channon, D. E., Cole, M., and Cole, L. (2000). A long-term study of Rattus norvegicus in the London borough of Enfield using baiting returns as indicator of sewer population levels. Epidemiology and Infection 125, 441–445.
A long-term study of Rattus norvegicus in the London borough of Enfield using baiting returns as indicator of sewer population levels.CrossRef | 1:STN:280:DC%2BD3M%2FmsVOgsA%3D%3D&md5=15a454cea4db0f1f13b2617255a01addCAS | open url image1

Channon, D. E., Channon, T., Roberts, T., and Haines, R. (2006). Hotspots: are some areas of sewer network prone to re-infestation by rats (Rattus norvegicus) year after year. Epidemiology and Infection 134, 41–48.
Hotspots: are some areas of sewer network prone to re-infestation by rats (Rattus norvegicus) year after year.CrossRef | 1:STN:280:DC%2BD28%2Fit1Kqug%3D%3D&md5=c909f2c78609235a752f0e4533f7b260CAS | open url image1

Colvin, B. A., Swift, T. B., and Fothergill, F. E. (1998). Control of Norway rats in sewer and utility systems using pulsed baiting methods. In ‘Proceedings of Eighteenth Vertebrate Pest Conference’. (Eds R. O. Baker and A. C. Crabb.) pp. 247–253. (University of California: Davis, CA.)

Davis, D. E., and Christian, J. J. (1956). Source changes in Norway rat populations induced by introduction of rats. The Journal of Wildlife Management 20, 378–383.
Source changes in Norway rat populations induced by introduction of rats.CrossRef | open url image1

Gardner-Santana, L. C., Norris, D. E., Fornadel, C. M., Hinson, E. R., and Klein, S. L. (2009). Commensal ecology, urban landscapes, and their influence on the genetic characteristics of city-dwelling Norway rats (Rattus norvegicus). Molecular Ecology 18, 2766–2778.
Commensal ecology, urban landscapes, and their influence on the genetic characteristics of city-dwelling Norway rats (Rattus norvegicus).CrossRef | 1:CAS:528:DC%2BD1MXpvFeiu74%3D&md5=d8e10fe33b35a142ff892ae0b0554cc8CAS | open url image1

Glass, G. E., Korch, G. W., and Childs, J. E. (1988). Seasonal and habitat differences in growth rates of wild Rattus norvegicus. Journal of Mammalogy 69, 587–592.
Seasonal and habitat differences in growth rates of wild Rattus norvegicus.CrossRef | open url image1

Gratz, N. G. (1994). Rodents as carriers of diseases. In ‘Rodent Pests and their Control’. (Eds A. P. Buckle and R. H. Smith.) pp. 85–108. (CAB International, Wallingford, UK.)

Heiberg, A.-C. (2009). Anticoagulant resistance: a relevant issue in sewer rat (Rattus norvegicus) control? Pest Management Science 65, 444–449.
Anticoagulant resistance: a relevant issue in sewer rat (Rattus norvegicus) control?CrossRef | 1:CAS:528:DC%2BD1MXjslSrtr0%3D&md5=a9c4eebc69593acb84a3f813de4d0588CAS | open url image1

Lambert, M. S., Quy, R. J., Smith, R. H., and Cowan, D. P. (2008). The effect of habitat management on home-range size and survival of rural rat populations. Journal of Applied Ecology 45, 1753–1761.
The effect of habitat management on home-range size and survival of rural rat populations.CrossRef | open url image1

Langton, S. D., Cowan, D. P., and Meyer, A. N. (2001). The occurrence of commensal rodents in dwellings as revealed by the 1996 English House Condition Survey. Journal of Applied Ecology 38, 699–709.
The occurrence of commensal rodents in dwellings as revealed by the 1996 English House Condition Survey.CrossRef | open url image1

Leirs, H., Lodal, J., and Knorr, M. (2004). Factors correlated with the presence of rodents on outdoor pig farms in Denmark and suggestions for management strategies. Netherlands Journal of Agricultural Science 52, 145–161. open url image1

Lund, M. (1994). Commensal rodents. In ‘Rodent Pests and their Control’. (Eds A. P. Buckle and R. H. Smith.) pp. 23–44. (CAB International, Wallingford, UK.)

Mantel, N. (1967). The detection of disease clustering and a generalized regression approach. Cancer Research 27, 209–220.
| 1:STN:280:DyaF2s%2FptlSnsA%3D%3D&md5=a00d20ea1fe26a45b0d65f0f0a48529aCAS | open url image1

McGuire, B., Pizzuto, T., Bemis, W. E., and Getz, L. L. (2006). General ecology of a rural population of Norway rats (Rattus norvegicus) based in intensive live trapping. American Midland Naturalist 155, 221–236.
General ecology of a rural population of Norway rats (Rattus norvegicus) based in intensive live trapping.CrossRef | open url image1

Meyer, A. (2004). Rats in sewers – out of sight – out of mind? Professional Pest Control 37, 4–7. open url image1

R Development Core Team (2010). R: a language and environment for statistical computing. R foundation for Statistical Computing, Vienna, Austria. Available at http://www.R-project.org/ [Verified 16 April 2012].

Rexstad, K. P., and Burnham, K. P. (1992). User’s guide for interactive program CAPTURE. (Colorado Cooperative Fish and Wildlife Research Unit, Colorado State University, Fort Collins, CO.)

Robertson, B. C., and Gemmell, N. J. (2004). Defining eradication units to control invasive pests. Journal of Applied Ecology 41, 1042–1048.
Defining eradication units to control invasive pests.CrossRef | open url image1

Singleton, G. R., Leirs, H., Hinds, L. A., and Zhang, Z. (1999). Ecologically-based management of rodent pests – re-evaluating our approach to an old problem. In ‘Ecologically-based Rodent Management’. (Eds G. R. Singleton, L. A. Hinds, H. Leirs and Z. Zhang.) pp. 17–29. (Australian Centre for International Agricultural Research: Canberra.)

Stroud, D. C. (1982). Dynamics of Rattus rattus and R. norvegicus in a riparian habitat. Journal of Mammalogy 63, 151–154.
Dynamics of Rattus rattus and R. norvegicus in a riparian habitat.CrossRef | open url image1

Twigg, G. (1975). The town rat. In ‘The Brown Rat’. pp. 76–91. (David and Charles Inc.: Newton Abbot, London.)

Venables, W. N., and Ripley, B. D. (2002). Modern Applied Statistics with S. (4th edition). (Springer: New York, NY.)

Ward, J. H. (1963). Hierarchical grouping to optimize an objective function. Journal of the American Statistical Association 58, 236–244.
Hierarchical grouping to optimize an objective function.CrossRef | open url image1

White, G. C., Anderson, D. R., Burnham, K. P., and Otis, D. L. (1982). Capture–recapture and removal methods for sampling closed populations. LA-8787-NERP, Los Alamos National Laboratory, Los Alamos, NM.



Rent Article (via Deepdyve) Export Citation Cited By (5)