Deer Smell First, Listen and Hear Later

by Kevin Strauss

Hunters have long advocated knowing their prey as a way to increase their
chances of putting venison in the freezer, but knowing how deer perceive their
world can have benefits for drivers as well.

With deer hunting season upon us, thousands and hunters are scouring the woods
for those elusive bucks and does. At the same time, in some areas, drivers are
seeing more deer on the side of the road, and November is a peak time for
deer-car collisions in Minnesota. But as I remember from my high school biology
class "correlation isn't causation." Just because two things happen at the same
time doesn't, by itself, prove that they are related. The reason that we see more
deer on the road this time of the year, according to DNR Area Wildlife Manager
Tom Rusch is because deer are traveling more during the rut, and because mowed
shoulders provide a good source of fall forage for deer. During the rut, male deer
have only one thing on their mind, mating. This means that males are chasing
females and this increased travel means deer are spending more time crossing
or near roads. On a recent evening trip from Duluth, I counted a half dozen deer
on the shoulder when normally I don't see any.

To drive safely in deer country, you need to know how deer
perceive their world. For a deer, it's most important sense is it's sense of
smell. When a deer smells a wolf or a human hunter, it runs off right away.
Sight and hearing are less important senses for deer. Their colorblind eyes are
geared to detecting movement and seeing in low-light conditions. Their hearing
is acute and directional, so they can more easily detect where a sound is
emanating from.

Ecologists describe how these sensory adaptations (or "tools")
have helped deer avoid or escape from their enemies for millions of years.
Unfortunately, while these adaptations work well when deer face wolves or human
hunters, they're not as helpful when deer encounter cars. First off, highway
cars move so quickly that a deer's senses of smell and is almost useless. Then
at night, bright headlights blind deer, making another sense useless. This
sudden sensory deprivation puts deer into their "fight or flight" mode. In many
cases, the frightened deer bolts to escape the perceived danger. In the wild, a
healthy adult deer can outrun most any wolf. The same isn't true when they try
to outrun cars. The unpleasant result for about 40,000 Minnesota drivers each
year is a huge dent and thousands of dollars in car repairs, or worse. Knowing
how deer perceive their world can help drivers avoid deer bumper ornaments.

First off, slow down. The slower you drive, the more likely that a deer will
hear or see you when you are still far away and retreat into the woods. Second,
use your high beam headlights to keep an eye on the shoulders for deer, but when
you see a deer, go to low beams to reduce your chance of blinding and startling
the deer. Third, don't rely too much on "deer whistles". I have lived in deer
country most of my life and used deer whistles off and on for most of that time.
Some people swear by them, but not the people who work with wildlife.

"Whistles don't work," said Rusch. "Deer can hear them, just like they can hear
your car, but the don't scare off the deer. I have seen deer ignore them much of the
time." Fourth, try to drive on busy roads and try to avoid driving at dusk and
dawn. Deer can be active at any time of day, but are primary "crepuscular"
animals who are most active in the low-light conditions of dawn and dusk. By
driving on busier roads, the constant activity is more likely to scare off deer
before you get there.

Fifth, remember that especially in November, deer travel
in pairs, either a doe and fawn or a doe being chased by a buck. Sometimes
people pay attention to the first deer that crosses the road and don't notice
the second one that crosses their path.

By understanding deer and taking a few precautions, we can get through
Nvember with our safety and cars intact.

The Ely Timberjay