Infrared Spectroscopy: A Powerful Tool Against Wildlife Crime

Although wildlife crimes such as poaching are beginning to become more regulated and enforced, this issue remains a significant problem globally, with an estimated $5 billion to $23 billion spent annually (1).

Wildlife crimes are often difficult to track because only six countries—India, South Africa, Namibia, Botswana, Kenya, and Mozambique—keep accurate poaching figures (1). Each country also deals with specific poaching cases; for example, elephant poaching is the most prominent wildlife crime committed in Botswana and South Africa, whereas Zimbabwe sees poachers target rhinos more than any other animal (1). Animals like elephants are endangered because their tusks are used to make tools and jewelry. Tigers, bison, and bears are killed for their hides to make coats, blankets, and other clothing items. Wildlife crimes contribute to several environmental issues, which include negatively influencing biodiversity and damaging the natural habitats where these animals reside.

Mother and baby rhino getting ready to drink. | Image Credit: © peterralph - stock.adobe.com

Because much of the evidence left behind in wildlife crimes are biological samples, such as animal hair, forensic analysis is needed to provide investigators with a better idea as to the crime that was committed and by whom. However, analyzing biological samples can be challenging to do without damaging the sample. Spectroscopic techniques, including attenuated total reflectance–Fourier transform infrared (ATR FT-IR) spectroscopy, are frequently used to test these kinds of samples.

“ATR FT-IR spectroscopy has several advantages over other analytical techniques, including its non-destructive nature, ease of use, rapidity, and cost-effective analysis of samples with little to no sample preparation steps, thereby making it an ideal choice for examining hair and other biological evidence in wildlife crimes,” said Rajinder Singh of the Department of Forensic Science, Punjabi University, Patiala (2).

Singh and his team also used chemometric models, principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), in their study to accurately classify hair samples from three different mammals (2,3). These models were used to test for whether they could differentiate between the different hair samples of three wild cat species: the royal Bengal tiger; Indiana leopard; and Snow leopard (2). They discovered in their study that PCA couldn’t separate hair samples between animals, whereas PLS-DA was able to do so.

“PLS-DA combines the characteristics of partial least square regression (PLSR) for reducing data dimensionality by selecting appropriate variables that maximize the covariance between the X and Y matrix with discriminant analysis to classify samples based on those derived variables,” Singh said. “PLS-DA successfully separated hair samples of three wild cat species into three distinct classes.

Along with ATR FT-IR, advancements in microscopy, PCR, and DNA sequencing have also allowed these techniques to be useful in investigating wildlife crimes. Microscopy, for example, has been useful in analyzing hair samples left behind by mammals because it allows analysts to determine the type of hair it is and figure out which animal it belongs to (4). For example, scanning electron microscopy (SEM) analysis allows scientists to compare parts of mammal hair from one another, including the root and shaft of the hair, as well as the inner core (4).

However, the challenge, according to a study Horia Chiriac and a team of researchers from the National Institute of Research and Development for Technical Physics and Alexandru Ioan Cuza University, is that biological samples need to be prepared for SEM analysis, which can be a challenge because of the time and equipment required (5).

Unlike SEM analysis, IR spectroscopy does not require expensive technology to conduct its analysis of biological samples. Because of this reason, it is cheaper and much more reliable out in the field (4). IR spectroscopy is particularly effective at studying fibers like fur.

However, IR spectroscopy’s effectiveness is dulled by its time-consuming nature. As a result, FT-IR spectroscopy has become the technique of choice over traditional IR when conducting this type of forensic analysis. FT-IR uses an interferometer to collect all wavelengths simultaneously, a process known as multiplexing. The resulting data, called an interferogram, is then mathematically transformed using the Fourier transform to produce the IR spectrum. This approach allows for much faster data acquisition.

That is why many laboratories are mostly using FT-IR spectroscopy to investigate wildlife crimes. For example, Barry Baker, section head of the morphology department at the U.S. Fish & Wildlife Service’s forensic laboratory in Ashland, Oregon, uses diffuse reflectance Fourier transform infrared (FT-IR) spectroscopy to study whether items were made from animals and therefore need to be investigated.

“Once you have a broad enough perspective based on experience, you can tell if a suspect item is made of sea turtle shell, for example,” Baker said to Chemical & Engineering News (6).

The Ashland Laboratory has become a popular laboratory for investigating wildlife crimes (7). Since the time of their investigation of 13 bald eagles found dead in Maryland, they have been expanding their laboratory, which have allowed them to conduct more work not only in investigating wildlife crimes, but also combat the illegal timber industry (6). Ed Espinoza, a forensic scientist at the laboratory, showcased the laboratory’s direct analysis real time–mass spectrometry (DART–MS) to highlight this point.

“This is the Ferrari of mass spectrometers,” Espinoza said to OPB (7). “It gives us very accurate data.”

Spectroscopic techniques can also be used to analyze bloodstains and body fluids, and this can also be applicable to investigators when conducting their investigations at the scene of the crime. One main concern with on-site investigation is that the equipment or analysts could potentially interfere with a sample, which could distort the results. Igor Lednev, a Williams-Raycheff Professor in Chemistry and SUNY Distinguished Professor at the University at Albany, State University of New York, said to Spectroscopy that advances in Raman spectroscopy, such as stand-off Raman spectroscopy, can potentially be a solution

“Stand-off Raman spectroscopy has significant potential for transforming forensic investigations by enabling the detection and identification of body fluid traces, such as bloodstains, from a distance,” Lednev said (8). “This capability would allow forensic investigators to survey crime scenes more efficiently without the need to physically disturb or contaminate evidence.”

Raman spectroscopy also can differentiate between human and animal blood. Lednev has also done work in this space, demonstrating that Raman spectroscopy can do so, which makes it a valuable technique of choice when investigating wildlife crimes if body fluids are discovered at the scene (9).

The State of Wildlife Crimes

Although wildlife trading is now more stringent in its regulation, thanks to the efforts of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), as well as the Lacey Act, wildlife crimes are still occurring at a considerable rate (10). The money in these illegal industries shows that far too many people see a huge profit in the practice.

But it’s not just the money that is driving it forward. Barry Cummings, an Idaho Fish and Game regional conservation officer, acknowledged that although the profit aspect of wildlife crimes incentivizes bad actors, some commit these crimes for other reasons that are not apparent.

“There are lots of motivations, and sometimes it’s opportunity,” Cummings said to The Spokesman-Review (11). “Sometimes it’s individuals that just simply must possess. Sometimes it’s individuals that think the law doesn’t apply to them. There are lots and lots and lots of reasons why people do the things that they do.”

References

1. World Population Review, Poaching by Country 2024. World Population Review. Available at: https://worldpopulationreview.com/country-rankings/poaching-by-country (accessed 2024-10-28).
2. Wetzel, W. The Future of Forensic Analysis: Using ATR FT-IR Spectroscopy in Identifying Animal Hair Samples in Wildlife Crimes. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/the-future-of-forensic-analysis-using-atr-ft-ir-spectroscopy-in-identifying-animal-hair-samples-in-wildlife-crimes (accessed 2024-10-24).
3. Bhatia, D.; Sharma, C. P.; Sharma, S.; Singh, R. Species Discrimination from Hair Using ATR-FTIR Spectroscopy: Application in Wildlife Forensics. Science and Justice 2024, 64 (3), 314–321. DOI: 10.1016/j.scijus.2024.04.002
4. Mazhar, A. The Role of Forensic Science in Wildlife Crime Investigation. Scientia Mag. Available at: https://scientiamag.org/the-role-of-forensic-science-in-wildlife-crime-investigation/ (accessed 2024-10-24).
5. Minuti, A. E.; Labusca, L.; Herea, D.-D.; et al. A Simple Protocol for Sample Preparation for Scanning Electron Microscopic Imaging Allows Quick Screening of Nanomaterials Adhering to Cell Surface. Int. J. Mol. Sci. 2022, 24 (1), 430. DOI: 10.3390,ijms24010430
6. Bomgardner, M. M. C&EN Profiles the U.S. Fish & Wildlife Forensics Lab, The Nation’s CSI: Wildlife Team. C&EN News. Available at: https://cen.acs.org/articles/94/i21/CEN-profiles-US-Fish-Wildlife.html (accessed 2024-10-24).
7. Neumann, E. Ashland Wildlife Lab’s Tools and Know-How Key to Detecting Illegal Timber Imports. OPB.org. Available at: https://www.opb.org/article/2023/04/07/ashland-wildlife-lab-combines-forensic-science-and-a-horse-trailer-to-confront-illegal-logging/ (accessed 2024-10-24).
8. Workman, Jr., J. Identification of Body Fluid Traces for Forensic Purposes: An Interview with Igor Lednev. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/identification-of-body-fluid-traces-for-forensic-purposes-an-interview-with-igor-lednev (accessed 2024-10-24).
9. Doty, K.; Lednev, I. Differentiation of Human Blood from Animal Blood Using Raman Spectroscopy: A Survey of Forensically Relevant Species. For. Sci. Int. 2018, 282, 204–210. DOI: 10.1016/j.forsciint.2017.11.033
10. ICE, Help Make Wildlife Traffickers an Endangered Species. ICE.gov. Available at: https://www.ice.gov/features/wildlife (accessed 2024-10-24).
11. French, B. The Spokesman-Review. Available at: https://www.spokesman.com/stories/2024/oct/03/idaho-grizzly-bear-killing-reveals-insights-into-i/ (accessed 2024-10-24).