We all know that human activity can influence the lives of nearby animals, especially those top predators that now have to play second fiddle to our ever-expanding interests. However, a new study has shown that not only do our actions impact them, but also our mere presence may cause majestic killers like pumas to grow so fearful that they change their hunting habits for the worse.
In the first-ever real-time tracking of leopard populations in India, researchers have determined that the big cats are surprisingly fearless when it comes to wandering near human neighborhoods. This was determined in a new GPS study, which has uncovered how these animals try to thrive in a man’s world.
That’s at least according to a new and fascinating study recently published in the Journal Proceedings of the Royal Society B, which details how, among pumas living in California, those living closest to humans were found to kill a lot more prey, but eat less of each kill, compared to pumas in more wild and secluded areas.
This was determined after a team of scientists from the University of California captured and tagged 30 wild pumas with GPS collars so they could track their movements. The territory and hunting grounds of these animals were then identified, breaking the pumas up into those that are living either near more rural or suburban human environments. The team also investigated kills, measuring just how much of each kill was eaten before a puma elected to slip away.
What they found was startling. In areas near a higher density of human housing, female pumas in particular were found to kill about 36 percent more large prey – mainly deer – than the more “rural” pumas.
Strangely, it wasn’t that the suburban pumas were hungrier. Instead, it appears that they are eating less of each kill – revisiting kill sites less frequently and spending less time taking their meals, compared to your average puma.
Figure: Behaviours that vary with housing density at predicted kill sites. Pairwise comparisons from Tukey’s HSD tests reported in superscripts, where different letters represent a statistically significant difference. Error bars represent two standard errors from the mean. Sample sizes of housing classes at female kills are: no housing, 719; rural, 83; exurban, 186; suburban, 71. Sample sizes of housing classes at male kill sites are: no housing, 389; rural, 32; exurban, 42; suburban, 15.
So what’s driving these pumas to act so differently? Fear of humans, the researchers suggest, is likely the primary cause. Female pumas are generally more cautious when hunting and eating compared to their male counterparts, largely because they are expected to birth and raise cubs.
That, of course, leads them to making an effort to avoid humans, even if that means smaller meals.
Unfortunately, “the loss of food from decline in prey consumption time paired with increases in energetic costs associated with killing more prey may have consequence for puma populations, particularly with regard to reproductive success,” the researchers report, saying that this extra caution may all be for naught.
Acces to the original article: http://rspb.royalsocietypublishing.org/content/282/1802/20142711
Other related published papers: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0112044