Odds of Getting a Male/Female Pair from Juveniles

group of efts

Since juveniles cannot be sexed, how many do you need to have in order to have a good chance of having at least one pair? If you take a truly random group of juveniles, your odds are as shown in the table below.

However, there are some factors that may cause you to get non-random distribution of genders. The following are some ways that a breeder can skew the sex ratio when distributing offspring.

  • If you get only the largest or smallest of the juveniles, you may tend to get mostly one sex.
  • If you choose a group with one particular color pattern, or the most aquatic individuals, you may be predisposed to getting all one sex. This has been documented in Triturus marmoratus, in which the brightest-colored offspring are usually female. A breeder who keeps all the brightly colored offspring will not be very amused by the result!
  • Some species have a phenomenon of sex reversal when the offspring are raised at unusually high or low temperatures. In these cases, the offspring may be predominantly of a single sex. This has been documented in Pleurodeles waltl.
Number of juveniles Chance of having at least one pair
1 0%
2 50%
3 75%
4 88%
5 94%
6 97%
7 98%
8 99%

© 2008 Caudata Culture, September 2004


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