By Mariana Furtado

The number of species requiring conservation interventions increases daily¹. Capturing and anesthetizing wild animals for collection of samples for research projects are essential for wildlife conservation and management, playing important roles in species survival¹,². However, the risks involved in capturing wild animals for sampling are high but not widely publicized²-⁹. The negative effects are not limited to physical injuries resulting from the capture methods used or the mortality of animals at the time of capture. There is an unknown and difficult to access number of late mortalities that can occur, as well as physiological and behavioral changes that animals can develop after capture, which can negatively influence their body condition, vital rates, and reductive success⁹-¹⁵. In five major wildlife species in Scandinavia, a capture mortality rate of 3.9% (n=380) was related in Eurasian lynx (Lynx lynx) and 3.4% (n=89) in gray wolves (Canis lupus)10. In semi aquatic mammals, the body mass of dominant individuals decreased considerably after capture events, and reproduction was negatively affected immediately following the capture event¹¹.

As an alternative, various non-invasive or minimally invasive methods have been developed and implemented¹⁶. It is possible to collect biological samples such as feces, fur, urine, saliva, and other body fluids for genetic, hormonal analysis, and pathogen research without having to capture wild animals²,⁴,⁸,¹⁶. The choice of methods depends on the study’s purpose, the target species’ characteristics, the study area, and the expertise of the research team. In recent decades, there has been a growing interest in wildlife research, especially in the health status of wild populations within a One Health context. This approach recognizes human, animal and environmental health as interconnected. However, it is crucial to collect high quality samples with minimal disturbance to the animals, thus adhering to modern ethical standards and regulations¹⁶.

Recognizing the importance of studying wildlife and aiming to minimize the impact of research on wild populations and individuals, research teams from the Institute of Biomedical Sciences of the University of São Paulo (USP) in partnership with Yale University and the Smithsonian Institute, are developing a novel non-invasive surveillance tool to study wild animal populations without the need to immobilize or even come into contact with the animal being sampled: S.W.A.B. (Spontaneous Wildlife Autonomous Biosampler). 

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To learn more:

1. Arnemo, J. M.; Ahlqvist, P.; Andersen, R.; Berntsen, F.; Ericsson, G.; Odden, J. et al. Risk of capture-related mortality in large free- ranging mammals: experiences from Scandinavia. Wildl. Biol. 12, 109-113, 2006. https://doi.org/10.1017/S0952836901000309
2. Breed, D.; Meyer, L. C. R.; Steyl, J. C. A.; Goddard, A.; Burroughs, R.; Kohn, T. A. Conserving wildlife in a changing world: Understanding capture myopathy – a malignant outcome of stress during capture and translocation. Conservation Physiology 7: coz27; DOI:10.1093/conphys/coz027. 2019
3. Brivio, F.; Grignolio, S.; Sica, N.; Cerise, S.; Bassano, V. Assessing the impact of capture on wild animals: the case study of chemical immobilization on alpine ibex. PLoS ONE 10, e0130957, 2015. https://doi.org/10.1371/journal.pone.0130957.
4. Caravaggi, A.; Amado, T. F.; Brook, R. K.; Ciuti, S.; Darimont, C. T.; Drouilly, M.; English, H. M.; Field, K. A.; Iossa, G.; Martin, J. E.; McElligott, A. G.; Mohammadi, A.; Nayeri, D.; O’Neill, M. H. K.; Paquet, P. C.; Périquet, S.; Proulx, G.; Rabaiotti, D.; Recio, M. R.; Soulsbury, C. D.; Tadich, T.; Wynn-Grant, R. On the need for rigorous welfare and methodological reporting for the live capture of large carnivores: A response to de Araujo et al. (2021). Methods Ecol. Evol. 12: 1793-1799, 202. https://doi.org/10.1111/2041-210X.13664
5. Palomares, F. A minimally invasive capture system for the safe and compassionate live trapping of jaguar and puma. Galemys, 30, 49-59, 2018. https://doi.org/10.7325/Galemys.2018.A5
6. Braud, C.; Mitchell, E. P.; Van der Merwe, V.; Tordiffe, A. S. W.; A veterinary survey of factors associated with capture-related mortalities in cheetahs (Acinonyx jubatus). J. S. Afr. Vet. Assoc. 90 (0):e1-e7, 2019. DOI: 10.4102/jsava.v90i0.1723
7. Widmer, C. E.; Perilli, M. L. L.; Matushima, E. R.; Azevedo, F. C. C. Live-trapping ocelots (Leopardus pardalis): traps baits, injuries, immobilization and costs. Biota Neotropica 17(1), 2017. https://doi.org/10.1590/1676-0611-BN-2015-0125
8. Zeiler, G. E.; Meyer, L. C. R. Chemical capture of impala (Aepyceros melampus): A review of factors contributing to morbidity and mortality. Vet. Anaesth. Analg. 44(5): 991-1006, 2017. https://doi.org/10.1016/j.vaa.2017.04.005 
9. Furtado, M. M.; Carrillo-Percastegui, S. E.; Jacomo, A. T. A.; Powell, G.; Silveira, L.; Vynne, C.; Sollmann, R. Studying jaguars in the wild: past experiences and future perspectives. Cat News, special issue, The jaguar in Brazil 4: 41-47, 2008.
10. Arnemo, J. M.; Ahlqvist, P.; Andersen, R.; Berntsen, F.; Ericsson, G.; Odden, J. et al. Risk of capture-related mortality in large free- ranging mammals: experiences from Scandinavia. Wildl. Biol. 12, 109-113, 2006. https://doi.org/10.1017/S0952836901000309
11. Mortensen, R.; Rossell, F. Long-term capture and handling effects on body condition, reproduction and survival in a semi-aquatic mammal. Scientific Reports 10:17886, 2020. https://doi.org/10.1038/s41598-020-74933-w
12. Holt, R. D.; Burger, L. W.; Dinsmore, S. J.; Smith, M. D.; Szukaitis, S. J.; Godwin, K. D. Estimating Duration of Short-Term Acute Effects of Capture Handling and Radiomarking. The Journal of Wildlife Management, 73(6), 989–995, 2009. https://doi.org/10.2193/2009-073
13. Omsjoe, E. H.; Stien, A.; Irvine, J.; Albon, S. D.; Dahl, E.; Thoresen, S. I.; Rustad, E.; Ropstad, E. Evaluating capture stress and its effects on reproductive success in Svalbard reindeer. Can. J. Zoll. 87: 73-85, 2009. https://doi.org/10.1139/Z08-139
14. Casas-Díaz E.; Marco I.; López-Olvera J. R.;, Mentaberre G.; Lavín, S. Use of acepromazine for stress control in Spanish ibex (Capra pyrenaica) captured by drive-net. Vet J. 183(3): 332-336, 2010. https://doi.org/10.1016/j.tvjl.2008.11.003
15. Ponjoan, A.; Bota, G.; Morena, E. L. G.; Morales, M. B.; Wolff, A.; Marco, I.; Mañosa, S. Adverses effects of capture and handling little bustard. Journal of Wildlife Management, 72 (1): 315-319, 2008. https://doi.org/10.2193/2006-443
16. Pearson, E.; Ortega, Y. K.; Ruggiero, L. F. Trap-induced mass declines in small mammals: mass as a population index. J. Wildl. Manag. 1, 684-691, 2003. https://doi.org/10.2307/3802675
17. Schilling, A.; Mazzamuto, M. V.; Romeo, C. A review of non-invasive sampling in wildlife disease and health research: What’s new? Animals 2022, 12, 1719. https://doi.org/103390/ani12131719