I am trying to induce tail autotomy at around 15 mm posterior to the vent. The lizards will try to run from me when I grab there, but they will not drop their tails. I've tried lifting them up to let them hang, I've tried prodding them with a paint brush (which I use to get them to sprint for sprint speed trials), and I've tried applying gentle pressure. They have no interest to voluntarily remove the tail. Hoping someone can give me some tips as I'm under a bit of time constraint to get them back into their home ranges. Thanks!
Depending on the species, the fracture plane is at the 5th, 6th or 7th vertebra from the sacrum in Sceloporus (Pregill 1992. Systematics of the West Indian lizard genus Leiocephalus). Perhaps you should slightly modify the point of pressure to induce autotomy. I have no first-hand experience with fence lizards, though.
This pic is from flickr (photo by Jerry Kirkhardt) showing the precise location of the breaking point in Sceloporus occidentalis, so you should grab your lizards’ tails posterior to this plane to autotomize them.
I agree with the prior comments. Just try in slightly different, more posterior position.
Thanks Balázs and Stan. I had tried several locations around that point and moving posteriorly but without success. I'm concerned that the lizards no longer perceive me as large enough threat after having been in the lab for a week, handled for sprint trials, handled for bite trials, handled for morphology, etc.??? I heard from another researcher that S. virgatus was a pain to get to autotomize, too. Will keep trying and really appreciate the feedback. Cheers.
Posting an update in case anyone comes across this later with the same question:
I took a piece of Lexan and drilled various sized holes that differed by 1/32" (0.8mm). I threaded the tails through the appropriate sized hole so that the tail couldn't go any further beyond where I wanted the break point and pulled back on the tail (with fingers as close to the Lexan as possible) as the lizard tried to escape (I did this on a very slick table top so that they couldn't run too far and were easy to hand-catch after autotomy). They dropped them pretty readily with this method and the break occurred +/- 1mm from where the tail was wedged in the Lexan.
- Badges
- Science topic
- Similar topics
- Mathematics
- Statistics
- Applied Statistics
- Survey Design
- Questionnaire