Florida Georgia Line

The Florida-Georgia Line. Really good country music group but also a really good way to look at bear populations.

Not about these guys

I've written a couple of articles on the difference in the size of bears within Florida. Here's one about how the size of the bears killed by vehicle strikes varies with somewhat larger bears killed in South Florida. Here's another from an old Facebook post where I looked at the size even greater size differences of bears killed in the 2015 hunt.

The geographic Florida-Georgia line isn't much of a line. The plants don't change much. The forage for bears should be pretty similar on both sides of the line. Therefore the size of the bears on each side should be similar unless there are government policies in place that cause differences in the states. By looking at bears in both states that were killed within a week of each other we should be able to tell if the weights are substantially different.

For a while I've had the weights of bears killed in the 2015 Florida bear hunt. I asked the state of Georgia under their Open Records Law for similar numbers so I could compare them. At first they said no, then ignored my repeated requests. After I escalated to the Georgia's Department of Natural Resources top lawyer they finally gave me the data I wanted. Florida posts data online. Georgia fights release of data until they can't hold it anymore. Advantage Florida.

Big Bear, Probably Georgian

Once I got the data I restricted the data even more. In this analysis we're only looking at bears killed in the counties that border the other state. In Georgia the border counties where bears were killed are Charlton, Clinch, Echols and Ware counties. In Florida the counties that touch Georgia where bears were killed were Columbia, Hamilton, Jefferson, Leon and Madison counties. These counties line up rather well across the border from each other so differences between the bear populations should be predominantly as a result of policies in the given states.

The size differences were pretty stark.

Average Harvested Bear Weights, Fall 2015

The Georgia male bears were an average of 155 pounds or 52% heavier on average than the Florida male bears. With the females the Georgian bears were 47 pounds 31% heavier.

In statistics there are always lots of tests that can be run on data. In this case I wanted to see if the bear populations as shown in the hunts could have come from the same populations. The thought is that there could be some random variation fooling me into thinking that the populations were of much different weights.

In this case I used a couple of t-tests. A t-test will tell us what the probability of having identical populations and yet getting strange results just by random variation. In this case the probability of the males coming from the same population is about .1%. For the females it comes out even less likely as there's a .09% chance of this kind of outcome happening by chance. In other words there's roughly 1 in a thousand chance of random variation causing either of these weight differences.

Hungry in Florida

So, why the differences in weights of bears that are across a line on a map? My working thesis is that the differences are because of the bear hunt. Georgia has held an annual bear hunt in South Georgia for many years. Florida held their first bear hunt in 2015 since the 1970's. I think the North Florida bears have outstripped the available food supply. This stunts the growth of the bears in north Florida and is the cause of much of the bear-human interactions there.

It's always good when an idea gets support from an unexpected source. When I first started looking at sizes of bears killed in the 2015 bear harvest I only had Florida to look at. I could see that the bears in south Florida were much larger than the bears in North Florida. The vehicle strike data also confirmed that. But now looking at the differences between the bears that grow separated by a state line it becomes apparent to me that the population of bears in north and central Florida needs to be reduced. And the bear hunt is the best way to do it.