Sunday, July 16, 2006

Heart Rate

Normal Great Horned Owls aren't above putting cats on their menu. Alice is anything but normal. She's terrified of cats.

She proved just how much cats freak her out a few years ago. My normal routine to take her to work involves going up to her room, getting her onto the correct perch (according to Alice there's only one "correct" perch to pick her up from), take her downstairs, she hops onto my husband's kitchen chair, I tie her leash to the leather jesses always on her ankles, and away we go.

Well, a few years ago she started flying back up to the hall railing every time I tried to take her downstairs. She made it very clear she wasn't going anywhere. I had my suspicions that the root of the problem was a stray cat that had started hanging around our yard. It sometimes hung around the bird feeders, and I'm sure Alice had seen it kill birds.

I was right. My husband "took care of" the stray cat and I had no more troubles getting Alice to go to work.

Our (outside) dog died last year, making Alice a pretty happy camper (she's deathly afraid of all dogs of all sizes.) But about a month after he died, a stray cat moved onto our property. It eventually got tame, despite rebuffing all contact with the cat for Alice's sake. Then a second cat moved in and the same thing happened...wild at first, but then it tamed down with no encouragement from us. Both are tomcats and they fight every day. And I've stopped feeding birds.

These cats bother Alice. Every time I take her out to the car to go to work, the cats are right there at my feet. Alice puffs up and does defense displays, hisses at them, etc., but the cats are too dumb to be scared of her!! How's that for sick and twisted: a Great Horned Owl that's deathly afraid of two cats who aren't afraid of the Great Horned Owl.

I realized just how much these cats are bothering Alice one morning when there happened to be no appliances, heat, air conditioning, or anything making any sound at all in the house. As she hopped onto the back of Ken's chair I could hear her heart pounding!

Her heart was just racing. It was very difficult to count the beats per minute, but I tried a few times and always got between 50-60 beats per 10 seconds. That's about 330 beats per minute! (Go to to hear it.)

That seemed really high to me, but I didn't know what her resting heart rate was for comparison. So a couple of times at work when it was perfectly silent and nothing mechanical was running, I was able to put my ear against her chest while she snoozed on her perch. This didn't seem to bother her in the least, and I came up with 15 beats per 10 seconds, or only 90 beats per minute. Wow, what a difference from the "cat heart rate"!

But birds have amazing cardiovascular abilities...way beyond what us mere humans can do. So I did a little checking to see what heart rate information I could find on other birds.

One study gave resting heart rates for three Snowy Owls (fairly close relatives of Great Horned Owls) outdoors in the winter in a range from 131-222 beats per minute (BPM). Another study gave a resting heart rate for the Ural Owl at about 215 BPM, with an excited heart rate (while being restrained) at 395 BPM. The same study showed resting and excited heart rates for Short-eared Owls at 224 and 445 BPM respectively. The excited heart rates were close to 200% higher than resting.

Alice is bigger than both Ural and Short-eared Owls, which would likely give her a lower heart rate. And she's housed at comfortable room temperature for humans (68-75 degrees Fahrenheit), accounting for some of the difference between her and these reports. Her heart rate increase from resting to excited, though, is approximately 367%. Uff da!

Not like this is the most scientific study ever done by any stretch of the imagination, but Alice is showing a major heart rate response to her fear of cats.

Anyone want a cat??? My husband has gotten to know these two and is reluctant to "take care of them".....

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