Lost Radio Station Or Real Demonic Growl?

So, this story took place when I was 14 years old, and my sister in her early 20's. I am now in my early 30's, but this experience still frightens me to this day. We lived in Southern Texas back then, in the countryside, dirt roads, mesquite trees, barbwire fences and all that crap. We often visited a cousin that also lived "in the sticks" because she was my sister's age and they commuted to college together.

One early evening, my sister asked if I wanted to join her for the drive to my cousin's house, and I agreed. It was about a 15 mile drive, but as the roads were all unpaved, some partially graveled, and some simply sand, one had no choice but to drive slow... And it usually took 40 minutes to reach our cousin's house. As my sister drove her old cutlass on the road, I remember looking out at the trees and just enjoying the calm (this part of Texas is very isolated), she swerved on the dirt road, because a rabbit jumped in front of the car. She unfortunately hit the poor thing and it died instantly. She kept driving and made me promise not to tell our mother... I don't know why, my mother wouldn't have cared, but I said "Okay."

Further along the boring drive, we could always only get limited radio reception... So we had some crappy radio station we didn't want to hear on, probably old country and western or something. Anyhow, as we stayed quiet because of what happened with the rabbit (no one feels good about hitting innocent animals right?) the station started to have more static and eventually just turn to silence. We then heard this loud growling, very unearthly... Like no animal I had ever heard before. Very loud, and we hadn't touch the turn dial since we first got in the car. The growl made us look at one another and then around at the deserted country road. My sister looked out her window and swore she saw a pair of red eyes staring from some wild shrubbery that we passed. She drove as fast as she could to my cousin's house and we told her and my aunt about what we saw, but my aunt didn't believe us. We didn't stay long, but headed home, only to have a few more rabbits jump in front of the car again on the return drive... Of which we avoided this time. My sister joked that this was all because we hit the rabbit earlier that evening.

I still don't laugh about that. She still remembers the growl. I have no clue what happened, but I am pretty sure the intensity of the growl we heard on the radio was not from a crossed station. I can't explain the rabbits either. My grandmother used to tell us "ghost stories" but mostly they were folklore, especially since we are Mexican- American, but nothing like this had ever been mentioned.

I have many other experiences that happened later in my life, and still occur until this day, but will write about those later. But I want to know what do you think the growl was?