A new technique using tigers' scent sprays, which are detected much more frequently in the wild than scat, may help conservationists better monitor tiger numbers the wild, suggests a new research.
The findings, published in the journal Conservation Genetics Resources, showed that DNA taken from tiger spray is just as good or even better than scat DNA in identifying individual tigers and their gender.
Tiger spray is a combination of anal gland secretions -- said to have a floral scent like citrus -- and urine, which contains DNA in the form of cells from the urethra.
"Genetic monitoring of tiger source populations is a conservation priority," said Anthony Caragiulo, post-doctoral researcher in the American Museum of Natural History's Sackler Institute for Comparative Genomics.
"The utility of this new method is really impactful because it will let us dramatically build upon the number of tigers that can be surveyed and, consequently, increase our understanding of these elusive animals -- hopefully before they are gone," Caragiulo noted.
Genetic tracking has traditionally relied on extracting DNA from scat collected in the wild.
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But in humid, tropical landscapes -- like those in Sumatra in Indonesia, where a number of tigers live -- scat often degrades before researchers can find it.
Scent sprays left by tigers on trees and overhanging leaves degrade less quickly, and can be detected by researchers between two and eight times as frequently as scat.
So, to boost the effectiveness of genetic monitoring of tigers in warm regions, the research team questioned whether DNA could be extracted from sprays.
The researchers collected spray samples from three captive tigers in Ontario, Canada, with cotton swabs that were then stored in tubes of buffer to help preserve the DNA.
The researchers were able to amplify non-coding DNA sequences and determine whether they are male or female.
"Although this new spray technique would not replace scat studies entirely, we now know that we can use both methods in conjunction to drastically increase our monitoring abilities," Rob Pickles, monitoring specialist for Panthera at global wild-cat conservation organisation, noted.
The next step for the researchers is to test the technique in the field, where it also could be used to monitor other scent-spraying animals, like lions.