Alligator snapping turtles (Macroclemys temmincki) are large aquatic turtles of the family Chelydridae, endemic to south-eastern United States in rivers flowing into the Gulf of Mexico (Pritchard, 1989). They are listed as Vulnerable in the 1994 Red Data List and face over-exploitation in parts of their range. Alligator Snapping Turtles have been present in Australian zoos for many years and at the Queensland Reptile and Fauna Park (Beerwah) since the early 1980's. Due to their large sizeand the difficulty of adequately exhibiting this species there is not a large requirement in Australia for specimens. Therefore, this is a managed species in this country (Banks and Meikle, 1994). Any captive breeding attempted must take into accountthe space available in Australian zoos for placement of new stock (Thomson, 1994).

         There are currently five adult turtles in Australian zoos, 1.1 at the Australian Reptile Park (Gosford), and 1.2 at the Queensland Reptile and Fauna Park (Beerwah). Beerwah's specimens, one male "Lighning" (Studbook No. 1) and two females "Lola" and "Lacey" (Studbook No.'s 2 & 3) have been enclosed together since the females were transferred from Ballarat Wildlife Park on 30 July, 1992 (Thomson, 1994). In this paper we announce and discuss the first captive breeding of this species in an Australian zoo.
    From the time of their arrival the females have exhibited breeding behaviour. Although no mating was observed, "Lola" started digging test holes in her enclosure, but never laid any eggs. On 6 December 1992, "Lacey" laid 12 eggs, of which eight were fertile, in the leaf mulch. They unfortunately died early during incubation. On 19 March, 1993, "Lola" excavated some test holes, then laid some eggs in the pond on the 25th March, which were all infertile.

     From the 11 March to 12 July, 1994, "Lightning" was observed mating on 11 occasions with the females, particularly after being fed. The females the females excavated test holes from 6 to 17 November, 1994, when both females laid eggs. The two nests were raided mid afternoon, immediately after egg laying had been completed and they had returned to the pond. A total of 36 eggs were collected. (Table 1.)
     Sex determination in the family Chelydridae is dependant on incubation temperatures (Yntema, 1979; Wilhoft et al., 1983), therefore, it appeared advantageous to split the clutches and incubate them separately. This would allow a sex ratio useful to the management plan to be to be obtained, so half of each clutch were incubated at 29-30°C, the other half were incubated at 25-26°C. The eggs were placed in a mixture of vermiculite and water, ratio 1:1 by weight. The containers were sealed, then opened once a week to allow the eggs fresh air and check them. On 13 January, 1995, all infertile and obviously dead eggs were frozen leaving four from "Lacey" and ten from "Lola". All eggs were measured and weighed and returned to the incubators. (Table 2.)

Navigation:    Page 1    Page 2