The following first appeared on Nov. 6th, 2006 on "WonderQuest" with April Holladay on the USA Today website.
A photograph I took that I call "Is that your tail or are you just glad to see me?"
Q: Why does the tail of a lizard continue to wriggle for a few moments after it has been snapped from its body? Why doesn't the wriggling stop immediately? (Submitted by Adrian Chan, Johor Bahru, Malaysia, to USA Today's April Holladay.)
A. Jean F. of Cloverdale, CA
The key to the question of why a lizard's tail continues to move after it has been separated from the rest of the lizard's body relates to:
- two muscle cell types ('slow-twitch' and 'fast-twitch'), and
- two systems (aerobic and anaerobic) used to deliver power to muscle cells.
'Slow-twitch' muscle fibers are required when slow movement (which doesn't involve stretching the muscles very far) must be sustained over a long time (such as would be needed in a marathon race).
'Slow-twitch' muscles rely on an aerobic power delivery system that requires much oxygen - along with proteins, fats and carbohydrates.
'Fast-twitch' muscle fibers are used when muscles are required to stretch to a great degree, but only over a relatively short time (as a dancer might use during a leap).
'Fast-twitch' muscles rely upon an anaerobic power delivery system which requires little oxygen but is based, instead, almost exclusively on glucose (sugar). This system also puts out much lactic acid as a waste product.
Since the lizard's detached tail no longer has access to the massive amounts of oxygen required for the slow, sustained movement of 'slow-twitch' cells, the 'slow-twitch' system fails almost immediately upon detachment.
Then, the 'fast-twitch' system kicks in and stretches the muscles in the tail to very near their maximum capacities which causes the detached tail to twitch vigorously.
When the glucose contained within the tissues of the detached tail at the time of separation is used up (approximately six to eight minutes in some lizard species) and, at the same time, the lactic acid waste product has reached a kind of 'saturation point', the 'fast-twitch' system also fails and the tail stops twitching entirely.
So, now, you know! ;o)
rate
email
print
link to this page
Comments: 19
When I was ice fishing several years back, my daughter caught a couple of good sized Pike, (one of my favorite for eating once I learned to properly clean them.) We "killed" them immediately, and the frigid icy air kept them well preserved.
When we got them home and cleaned them, their flesh "quivered" frantically, even as I breaded and fried the flesh. (Now that I look back on it, that's probably when my daughter first became a vegetarian - the whole thing freaked all of us out!)
It's like the severed flesh didn't "know" it was dead yet, and the reaction of the live muscle tissue you described above accounts for this perfectly. Once the muscle cells die, the twitching stops. (PS: the cooking DID stop the twitching! I don't think I could eat twitching flesh of any sort!)
Thanks for the detailed reasons!
You are most welcome, Genine! I thought it was a very interesting question so I researched it thoroughly and wrote (apparently) an excellent answer... (At least Ms. Holladay thought it was!)
Thanks for the info.
Thanks so much for posting this to
my group
I thought it was, too, Nana! Thanks!
... And frog's legs jump in the frying pan, too, Jerri... ICK.
Nope, Susan... "muscles", actually...
Uh-oh, Tinch! I get so mad at Plunkett if he goes after a bird... Still, one cannot change thousands of years of hunter instinct, can one?
I'm not kidding - we had a chicken farm when I was very little. My grandpa would put them on the wood chopping block and ax them and they always told me that the chicken sometimes still flew off without it's head for a few feet.
Well - the interesting part was - we had one rooster who was mean and decided to go after me. It was my grandpa's favorite rooster so he didn't want to kill it and he didn't really believe it when my Mom told him.
One day out in the yard - he saw it with his own eyes. Grandpa was so incensed when he saw the rooster attack a 2-3 year old little girl - he grabbed him and axed him on the spot.
My Mom told me that rooster was so mean he actually flew over the entire house (and you know we are talking about min 15 feet on a german house) - that's how mean spirited that critter was. ..........the whole family swore that really happened!
argh!!! lizard tails.... twitching and detached... I gotta cross my legs just thinking about it... shivers
Yep, Rose, I'd venture to say that is why this happens with chickens, too... Roosters can be very, VERY mean indeed! I've had run-ins with 2 different ones in my life... They were far more aggressive than even the most aggressive dog I've ever had to deal with...
Thanks, Rose... :o)
ROFLMBO, Pat!! There's a fundamental difference between "tails" and -- and -- oh, YOU know... Didn't mean to cause any undue trepidation, there... sorry 'bout that!
It IS, isn't it, Shelbia? Thanks for commenting!
I always thought it twiched so the lizard could escape and the attacker would take the tail.