On March 9th, you might expect to wake up a little groggy. That’s because at 2 AM that morning, our clocks will spring an hour forward as we enter daylight savings time. Although the bi-annual shift of the clock can bring inconvenience to many – whether by altering sleep schedules or from the frustration of forgetting how to change the settings on our manual clocks – one species in particular faces the effects of a clock switch with far more consequence than us.
For deer, changing our clocks can spell death.
If you drive, you’re likely no stranger to seeing the gruesome scene of a dead deer on the side of the road. Over 2 million deer collisions occur in the U.S. each year. And when abrupt shifts in human activity occur, like the hour difference in traffic patterns that comes from changing our clocks, deer are caught off guard and are more likely to fall victim to the ever-present monster of wildlife-vehicle collisions.
The most deadly time shift for deer won’t come until the Fall. Research has found that deer collisions are 14 times more frequent 2 hours after sunset when compared to 2 hours before sunset. When the Autumn switch to standard time occurs, it alters peak traffic volumes from before sunset to after sunset, and there is a 16% spike in deer collisions.
In fact, the annual peak of deer-vehicle collisions occurs during the two week period after the switch from daylight savings time back to standard time. In addition to the switch in traffic patterns, the Fall also signifies mating season for deer. Called the “rut,” this period of time sees increased deer activity by as much as 50%. And deer can be more erratic.
If the country were to see a shift to permanent daylight savings time, it could be life saving news for deer and human lives alike. One model predicts that this shift would prevent 36,550 deer deaths, 33 human deaths, 2,054 human injuries, and $1.19 billion in collision costs annually.
On the flip side, if permanent standard time were adopted, collisions would be predicted at an even larger magnitude, including over $2 billion in additional costs. The data makes it clear: drivers in the dark spell danger for deer.
The Bigger Picture
This issue is a microcosm of a larger problem: habitat fragmentation. Roads, cities and other development all across the country divides and fragments animal habitats. Seeking food or mates, these animals often have no other choice but to risk their lives by crossing a busy road. This leads to the death of around a million vertebrate animals every single day. Hundreds of human deaths, thousands of injuries, and over $8 billion in property damage are also incurred annually from wildlife-vehicle collisions.
For now, as the debate rages on about whether to end daylight savings time, make it permanent, or keep adjusting our clocks twice a year, we have one key tip.
Be sure to keep your eyes on the road, because when our clocks change, deer don’t always get the memo.
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Casey works on campaigns that protect and save America’s wildlife. Casey lives in Rocklin, California, and enjoys hiking, DJing, and rooting for the San Francisco Giants.
