ABSTRACT If it is assumed to be a reproductive attempt for a young tortoise deliberately to mount another, using its front legs to raise the anterior portion of the body, and then to bring together the cloacas of the two individuals, along with the groaning vocalizations produced by males when they attempt copulation with females, such vocali zations were noted in the possible reproduct ive attempts before copulation among juvenile tortoises in the pre-adaptation corrals of the Raising Center of the Galapagos National Park Service (GNPS) and the Charles Darwin Research Station (CDRS). To our knowledge, copulation did not occur in any of the torto ises involved were sexually mature when tho bservations werte made. We interpret these behaviors as representing pre-copulatory reproductive attempts in young tortoises, regardless of sexual maturity. In all cases, the observations occurred during the warm season in Galápagos, January to March, which is the time when copulation occurs under natural conditions.

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    ABSTRACT: The giant tortoises in the Galapagos Archipelago diverge considerably in size, and in shape and other carapace characteristics. The saddleback morphotype is known only from insular faunas lacking large terrestrial predators (i.e. Galapagos and Mauritius) and in Galapagos is associated with xeric habitats where vertical feeding range and vertical reach in agonistic encounters are adaptive. The large domed morphotype is associated with relatively cool, mesic habitats where intraspecific competition for food and other resources may be less intense than in xeric habitats. Other external characteristics that differ between tortoise populations are also correlated with ecological variation. Tortoises have radiated into a mosaic of ecological conditions in the Galapagos but critical data are lacking on the role of genetic and environmental controls on phenotypic variation. Morphological divergence in tortoises is potentially a better indicator of present ecological conditions than of evolutionary relationships.
    Biological Journal of the Linnean Society 12/1983; 21(1‐2):165 - 176. DOI:10.1111/j.1095-8312.1984.tb02059.x · 2.26 Impact Factor
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    ABSTRACT: Eight of the 11 surviving races of Galápagos tortoises are threatened due to decreased population sizes and predation and/or competition by introduced mammals. Systematic hunting has been effective for controlling and even eliminating goats on the less elevated, more sparsely vegetated, smaller islands and for controlling pigs, even on some of the larger islands. However, the method has been ineffective against dogs and cats and it is doubtful that it could be used to eliminate goats or pigs on the more elevated, larger islands which have a diversity of vegetation zones. Alternative control or extermination methods are being sought and tested for these feral mammals and black rats. In an attempt to increase yearly recruitment of hatchlings, lava corrals have been constructed around nests, resulting in almost 100 per cent success in preventing nest destruction by pigs; but the method was ineffective against dogs. While other control methods are being sought, young of the endangered races are being hatched and raised in captivity for restocking of endemic populations. During the past seven years, improved and highly successful techniques have been found for (1) establishment of breeding colonies and construction of artificial nesting sites, (2) transport of eggs from wild nests, (3) incubation of eggs, and (4) raising of young in captivity. By August 1972, 231 young of six races were being raised, and 71 4·5–6·5 year old captive raised tortoises released on Pinzón in 1970 and 1971 were in good condition and growing rapidly. The advantages of conducting the breeding/raising programme in the Galápagos rather than foreign locations are discussed.
    Biological Conservation 07/1974; 6(3-6):198-212. DOI:10.1016/0006-3207(74)90068-8 · 3.76 Impact Factor
  • Morphometrics of Galápagos Tortoises: evolutionary implications. págs 107-122. . pp.


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