variation in key limiting traits (Storfer 1996). In painted turtles (Chrysemys picta)
the sex ratio is skewed towards females under warmer conditions. Populations are
now managed so as to raise males and balance the sex ratio as global warming
proceeds ( Janzen 1994). Conservation, therefore, should focus on preserving quan-
titative traits associated with stress resistance (Storfer 1996).
Genetic information on individuals and populations can be obtained from small
quantities of DNA obtained non-invasively. For example, hairs from mammals can
be obtained from hair traps. Individuals can then be identified for censusing, as in
the very rare hairy-nosed wombat (Lasiorhinus krefftii) of Australia (Sloane et al. 2000).
DNA from fecal samples was used to differentiate feces of Mexican gray wolves (Canis
lupus baileyi) from those of coyotes (C.latrans) (Reed et al. 2004). DNA from fecal
samples can be used to identify individuals, and from this estimate population size.
This technique was used to estimate a population of European badgers (Meles meles),
by estimating individuals and applying rarefaction analysis (Frantz et al. 2004). DNA
from fecal samples has the added advantage that dietary information can also be
obtained. Coyote populations in Alaska declined when their staple prey, the snow-
shoe hare, declined. Individuals (identified by DNA analysis of feces; Prugh et al.
2005) which ate other, less risky food species had greater chances of surviving the
period of food scarcity than those eating risky species such as porcupines (Erethizon
dorsatum) (Prugh 2004). We should, however, be careful with interpretations,
because there are several possible biases in sampling populations (Mills et al. 2000).
The characteristics of individual animals are shaped by the process of evolution through
the associated process of speciation. Geographic barriers, earth movements, and the
migration of climatic zones split up the distribution of species, the separated com-
ponents then adapting to their own disparate environments. Evolution of higher order
taxa leads to convergence on one hand and radiation on the other.
These large processes determine the detailed characteristics of the individuals of a
population, their morphological and behavioral traits differing within populations and
among populations according to genetic programming. Molecular methods allow us
to determine more accurately the genetic constitution of individuals and the genetic
differences among races, species, and higher taxa. These techniques can be used for
assessing parentage and genetic relatedness, censusing, identification of species in law
enforcement, and determining genotypes and phylogenies for conservation.
ANIMALS AS INDIVIDUALS 35
3.9 Summary
