Scats are very often
the only reliable indicators of the presence of a species, and they can provide
a wide array of information about diet, abundance or presence/absence, physical
health, stress levels, and parasite loads. Scat analyses provide vital
information for management and conservation planning of species in different
regions. Many indicators of species abundance and population health are based
for a large part on scat surveys.
In simple ecosystems,
with single-species occupying each trophic level,
scats differ morphologically between levels and their assignment to species is
usually not problematic. Difficulties arise where species of concern to
conservation have overlapping ranges and similar diets. Jaguar and puma are a
prime example, coexisting over much of their geographical range with broadly
similar dietary needs, but some differences in favoured prey that may be
crucial from a conservation management perspective. Classical methods of
distinguishing jaguar from puma scats, based on size, shape and neighbouring
footprints (if substrate allows), have proved very unreliable for identifying
species. A method that measures the bile acid levels within scats has been used
to differentiate jaguars from pumas, but its reliability is no greater than
80%. At present, genetic analysis is the only technique available to
distinguish jaguar from puma with certainty. Although reliable, the method is
very expensive and has limited success (25-50% of scats) due to degrading of
target DNA. The tropical environment of
Our aim is to test an
alternative method that makes use of the extremely powerful olfaction
capabilities of dogs to distinguish target species by odour. Dogs are trained
on the scats of captive animals fed different diets, and on scats that have
been decaying for different periods. Once trained, the dogs can be used on the
target scats and can differentiate between species just as a narcotics dog can
sniff out particular drugs. The method has already proved successful in distinguishing
scats of temperate carnivores (grizzly bears versus black bears and kit foxes
versus red foxes and coyotes) but has yet to be tried on tropical carnivores.
The tropics contains most endangered species of carnivores, but it also
presents special difficulties in terms of the fast rates of decay of scats and
the general lack of research funds in tropical regions for running lab-based
analyses. The use of dogs potentially has similar reliability to genetic
analysis, while being faster and cheaper. Most importantly, it will have
potentially a much higher success rate since it relies on overall olfactory
pattern, which stays intact longer than the DNA strings required for genetic
analysis. Scats retain much of their smell for periods of weeks to months
because they are used by carnivores in olfactory communication signals. In
addition to identifying species, dogs could potentially distinguish sex and
individual.
We intend to validate
the method by training the dogs twice for both jaguar and puma and cross-checking
different individual dogs. Results will be compared with genetic analysis of a
subset of the samples. The method will be applied to an existing sample of ~315
jaguar/puma scats collected from
This project is funded by the People's Trust for Endangered Species.