Pumas are scared off their food

Living near human homes causes pumas to be scared off their food, according to a recent study.

After killing large prey like deer, a puma, or mountain lion, will normally remain nearby for a few days, snacking on the carcass whenever it gets hungry. If it doesn't feel safe, it will sleep elsewhere during the day and only return to feed under cover of darkness.

Wanting to know more about how humans affect this behaviour, a team from the University of California tracked the movements of pumas fitted with GPS collars. Their findings, published this week in Proceedings of the Royal Society B, show that when pumas made kills near human housing they abandoned their kills much more often, retreating up to a kilometre every day and returning every night.

All this travel back and forth wastes valuable energy, and leaves the carcass unguarded against scavengers. This means that these pumas have to kill more deer to survive than those who can stay with their kills. This could increase pressure on local deer populations, affecting their numbers and behaviour.

The potential knock-on effects don't stop there. Scavengers such as racoons, coyotes and bobcats also play an important role in the local ecosystem. "In terms of scavengers... you would imagine that these animals are going to benefit from having an increased availability of this really high-quality food source," explains Justine Smith, part of the research team. "There's also the possibility that they might be putting themselves more at risk because scavengers do occasionally get killed by pumas at these kill sites."

Ecosystems are highly complex, and a change in the behaviour of a top predator can have far-reaching consequences. "What we're seeing is really that the humans are the behavioural top predator, if you will, that's changing the feeding behaviour of the natural top predator, which is the puma," says Smith.

Fortunately there are measures being put in place to minimise disturbance caused by human settlement, including plans for new residential developments which are more clumped and can be segregated from the pumas' habitat instead of sprawling across the landscape. Smith says, "In terms of places that are already developed, there are a number of potential options that could help: constraints on what kind of light bulbs are there, how strong lights can be, sound ordinances might help to mediate disturbances to animals."

With human population still increasing rapidly, it is important that we find a way to house everyone while minimising the impact on what little natural wilderness still remains.