Raising young newts

[matthew]

(This is a question that I'm posting here because it isn't species-specific. I'm sure it has been addressed before I can't find an answer by performing a search.)

Doing the rounds yesterday, feeding and cleaning my zoo-at-home, I was struck by the different individual growth rates of many of the newt species I have raised, whether it be marbleds, bandeds, spanish alpine or sharp-ribbed.
I always end up with a bell-shaped curve: a 'normal' middle range tapering out to a few individuals at the extreme edges.

Is it only me who ends up with this?

I am particularly struck by the ability of one individual to dominate a group of morphed youngsters... for me, there always seems to be a Schwarzenegger in the group.

Is there a way to ensure more even growth rates?

Do people remove stragglers / runts for extra care and attention or take out the dominating super individuals for solitary confinement?

What are the factors here? I have tried using smaller homes (greater food density), bigger homes (more room = less bullying?)and have always been very, very generous with food (my observation is newts getting insufficient food lose weight quickly).

I plan to raise eggs again this year and want to get it right.

(By the way, I don't have this issue with the fire sals I raise, although I have posted about the aggression I have seen in a juvenile group.)

Cheers for any ideas,
M.

 

[alan]

It's entirely normal in a relatively outbred population and you can't eliminate this. When many random factors interact (genetics, diet, etc), the result is a normal (bell-shaped) frequency distribution of length, weight or whatever parameter you're measuring. For a fuller explanation, see:
http://www.amazon.co.uk/exec/obidos/ASIN/0471498351/ajcann

In the wild, the extremes would be eliminated and the normal individuals would predominate. I'd bet you'd see the same thing if you raised fire sals in the same numbers.

 

[matthew]

Cheers for a very interesting link, Alan.

 

[jennifer]

Indeed, Alan, I'm impressed.

Matthew, I have certainly observed the same phenomenon. In fact, I think it's one of the biggest problems facing anyone that wants to raise a large number (>10) of larval newts. As you suggest, supplying more than ample food helps. But it still comes down to personality, with the less-shy offspring growing faster.

I usually end up separating offspring into groups based on size. This at least prevents bullying and any possible cannibalism.