Chilling the Eggs During Incubation
as the Key to Successful Breeding of the Annam Leaf Turtle
- by H. ARTNER -
A breeding report of a group of two males and three females of the Annam Leaf Turtle Mauremys annamensis over
a period of several years is given. Notes on the systematic status of the genus Mauremys are provided followed by a detailed
description of the captive maintenance conditions.
The turtles are almost exclusively fed on an artificially colored feeding gel containing fish, meat, carrots, chicken liver, shrimps, and additional vitamins and calcium. The author had better breeding results
when the sexes were kept separately all year except for mating attempts when one male and one female were put together in small
aquaria under constant observation. A seasonal rhythm like in the distribution area in central Vietnam was offered. Hibernation
took place at 8–12 °C for 3 months. Mating occurs in spring, when the female is placed into the male’s tank.
Sexes are kept separately during the rest of the year. After noticing the presence of a female, the male sometimes bites the female’s head and forelimbs. If the female is receptive to mating, she will remain immobile, raise the hind part of her carapace, and extend the hind feet
outwards. The male will then immediately mount her from behind. If the female does not remain immobile, the male will chase
her and mount her when she stops. He will then bite into the female’s neck in order to force her to retract it and to extrude her
anal region. Copulation lasts 5–10 minutes and during that entire period the female remains still. Finally the female tries to get
rid of the male by shaking him off her carapace.
Clutches usually comprise between 4 and 8 eggs.
A second and even a third clutch per female is possible during one
season. In M. annamensis the eggs need a chill period of about 30 days at 20 °C to end
diapause and to dramatically increase hatching success. This was practiced in 2000 for the first time. Mauremys annamensis
hatchlings usually emerge after 90 days incubation time at constant 29 °C (including the approximately 30 days chill period),
and have average carapace lengths of 35 mm and weigh 8 g. Rearing the hatchlings takes place in very shallow water and only
after some time the water depth is increased to about 8 cm. Juveniles are also fed a diet of artificially colored turtle feeding gel,
earthworms, meat, Tubifex worms, fish and pellets. Since 2000 over 65 hatchlings of M. annamensis were produced by this
breeding group. Key words: Reptilia; Testudines; Cryptodira; Geoemydidae; Mauremys annamensis; maintenance conditions; captive breeding; diapause; rearing hatchlings.
The Annam Leaf Turtle Mauremys annamensis (SIEBENROCK, 1903) is a severely threatened freshwater turtle species from central Vietnam (BOURRET 1941, IVERSON 1992, STUART et al. 2002).
Human consumption of this species has apparently been the main cause of its decline as it has traditionally been consumed locally and in recent years the species was exported from Vietnam to China in
relatively large numbers (VAN DIJK et al. 2000).
As with many other species of the area (ARTNER 2006), detailed data on the species’ natural history
are still not available. Only trading routes of the species from their area of origin in central Vietnam to
Chinese food markets have been investigated so far (LEHR 1997, HENDRIE 2000). A single female
was captured using a trap in a lake in Vietnam’s Quang Nam province according to an article published in the Vietnam News of December 13, 2006 (source: www.asianturtlenetwork.org).
The author is not aware of large scale breeding attempts as published for other East Asian species in
southern Chinese turtle farms although there are efforts on Hainan Dao (P. P. VAN DIJK pers. comm.).
A report by ZHOU et al. (2006) does not list the species either among those found in several turtle
farms on Hainan in late 2004.
... read the whole article in our EMYS magazine, for members only!