Well my tincs have always done it from baby to adult, when excited or feeding or dealing with another tinc (the twitching the toes). I guess I never questioned if it was a defect I just thought it was something they did to communicate like vibrating their throat. All I know is all my Tincs are healthy my adults are big and nothing has ever been wrong with them so I just let them do what they do.
Chantel
-----
Chantel a.k.a. sillygirl
"I came, I saw, I adopted"
2.2 green anoles (Stumpy (M)), and the rest remain nameless.
1.1 green tree frogs (Romeo & Juliet)
1.2 Firebelly toads
0.0.5 D. tinctorius (Cobalt froglets)
0.1 Anerythristic 'B' (Charcoal)corn snake (Popcorn)
0.1 Snow Corn (KandyKorn)
0.2 Amel Corns (KornSilk & KornMuffin)
0.1 Normal Corn (PepperKorn)
1.0 Creamsicle Corn (Kream)
0.0.1 Giant African Millipede
2.4 Domestic house cats (Bad Boy (m), Bart(m),Sasha(F),Little Bit(F),Spirit(F)
1.0 Rottweiler (Jake)
2.5 Rats (Mouse, Socks, Silver, Squishy, Fox, Lucky and B**CH)
1.3 Mice (My step-daughter seems to think they are pets)
2.0 Betta (Sushi, Blue)
1.0 Husband (David, who loves all my critters too)