PSU Deer Study

All true cervids (deer) have evolved antlers as part of their breeding strategy. These marvels of evolution are used to compete for the affection of females (except the Chinese water deer – it has tusks!).

Sparring by bucks is actually a ritualized behavior – antlers are only slightly stronger than the physical forces experienced when two males butt heads (literally!). This makes sense. Most of the components of antlers are simply resources “stolen” from the deer’s skeleton. Why build the titanic when a yacht will do?!

The sparring ritual involves a clash antlers. The two males push against each other testing their strength and resolve. Typically it’s over quickly. One deer senses he cannot win and he swiftly withdraws.

Don’t waste time or resources on a fight you can’t win. Game over. No one gets hurt (except perhaps the loser’s feelings).

Antlers are also kind of like a walking advertisement to the opposite sex. Another way for females to assess whether a buck has “the right stuff.” Like a walking billboard of your potential assets for the world to see.

So this “He who has the Biggest Antlers” seems like a sensible way to make sure only the “best” males do more of the breeding (NOT most of it, just a little more of it).

But then again, we’re talking about males and they’re not always sensible when it comes to mating (perhaps an understatement).

Case in point, Buck #12786. He was captured in Potter County in 2013 as an adult (at least 2 years old – and now at least 4.5 years old). Last week we received a mortality signal from his collar. The field techs hiked in to recover the radio-collar (and hopefully the deer).

They found the collar and the deer. He died next to a log with his hind legs splayed out behind him. Like he was running downhill and stumbled. Deer don’t usually fall while running. They are kind of experts at running, especially in the woods.

Deer-Forest Study

Deer-Forest Study

All they could see was a very tiny wound on his chest and hind leg. To the lab! There Dr. Justin Brown, the PGC’s wildlife veterinarian, could assess exactly what happened.

Dr. Brown found multiple lacerations (cuts) and puncture wounds throughout the body. But the coup de grace was a puncture wound between the ribs that tore the pericardium (the “sack” that surrounds the heart). Buck 12786 died from blood loss into the lung cavity.

Deer-Forest Study

A scan for metal fragments turned up nothing, meaning no bullet or arrows.

So what event lead to Buck 12786’s demise? Given the multiple puncture wounds, the most plausible explanation is that Buck 12786 was fatally gored by another deer.

The plot thickens.

The odds of this happening? Probably 1 in a million – it’s the first case we documented since we began radio-collaring bucks in 2002 (but see this story about Buck 8917). However, there are many documented instances of injury and even death from sparring… missing eyes, locked antlers, pierced skulls, you name it.

And remember Buck 8917 and the last buck to see him alive?! Hmmmmm.

But dying from a fight over a “girl” is rare. And it should be for good reason – because it doesn’t make evolutionary sense for a competition for mates to have a high risk of mortality. Otherwise, you can seriously reduce the gene pool – and fast.

I suspect Buck 12786 met his equal. Both sensing they could “win,” the two bucks continued to spar and it turned deadly.

Game over for Buck 12786.

-Duane Diefenbach

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