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Angonoka is the name given by the Malagasy, that is, the inhabitants of Madagascar, to the most representative tortoises of their country. These reptiles, belonging to the species Astrochelys yniphora , are also known in Europe as ploughshare turtles, because the ventral part of their carapace, called the gular shield, protrudes between the two front legs, as occurs with the front wheel in a plow machine.
Angonoka tortoises are distinctive in appearance: they have a domed, golden-brown carapace with growth rings on each plate, giving them a beautiful appearance. However, these characteristics have made them one of the favorite pets for collectors and, consequently, prey to species trafficking.
Characteristics
This species presents sexual dimorphism, that is, males and females exhibit different physical traits. The males, larger than the females, measure between 361 to 486 mm and weigh between 7.2 to 18.9 kg; in addition, its gular shield is more prominent and its tail is longer and thicker. The females, meanwhile, measure between 307 to 426 mm and weigh between 5.5 and 12 kg. Their reproductive period is approximately 4.5 months and they lay between 1 and 6 eggs, of which a little more than half hatch, thus producing 4.3 offspring per year for each reproductive female. These animals are herbivores, although they also feed on the dried feces of carnivores and wild pigs.
Habitat and distribution
Angonoka tortoises are endemic to Madagascar, that is, their population is only found naturally in that country. Currently, they are distributed in the Baly Bay National Park. Although the suitable habitat for the individuals extends almost 70 km 2 , in 2008 it was detected that the tortoises only occupied 12.4 km 2 and formed a wild population of about 600 individuals, of which only 200 were adults.
threats
Angonoka tortoises are considered Critically Endangered on the International Union for Conservation of Nature (IUCN) Red List because their population has declined drastically in recent decades. For this reason, it is believed that in less than 15 years the species will have disappeared. The current state of threat responds to factors such as the exploitation to which populations have historically been subjected and the loss of their natural habitat; the latter has happened as a result of man-made fires to increase grazing spaces for zebu cattle.
Although habitat destruction is a determining factor in the decline of the species, overexploitation is a more serious and immediate threat, as these tortoises have become attractive to collectors, for whom status is increased by acquiring rare species. . Precisely, the Angonoka are considered “the golden turtles”, which has increased their demand in illegal animal trade networks.
Protection Strategies
In response to the plight of the species, it was protected by the national legislation of Madagascar. In addition to belonging to the IUCN list, it was also included in the registry of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).
Added to this, the area in which the species is distributed was classified as a national park in 1997 and has had a permanent presence of the animal protection authorities since 2001, accompanied by a group of rangers who control both possible traffickers and sources of fires. . To further protect the turtles, agreements have been reached in which the researchers refrain from reporting the exact location of the individuals.
On the other hand, the species was incorporated into various conservation strategies. The Durrell Wildlife Conservation Trust , the Madagascar Government Department of Water and Forests, and the World Wide Fund for Nature have conducted successful captive breeding and reintroduction programs, both in Madagascar and in US and European locations. As complementary efforts, environmental education strategies have also been implemented with local communities.
tattoos that save lives
Another strategy to save Angonoka tortoises has been to devalue them in the international pet market. The process consists of marking the shell with large numbers, which causes them to lose commercial value.
However, the tools with which adult individuals are marked do not work with the youngest, who are the favorites of traffickers; this due to the soft nature of the shell. For this reason, they began to tattoo the little ones, which worked at first. Two years later, the tattooed numbers had faded due to the growth of new keratin, so the conservation team continues to develop methods that allow the young animals to be marked longer, until the moment they can be permanently engraved on their shells. .
Sources
Thomas EJ Leuteritz, Miguel Pedrono. Turtles on the Brink in Madagascar: Proceedings of Two Workshops on the Status, Conservation, and Biology of Malagasy Tortoises and Freshwater Turtles . In Christina M. Castellano, Anders GJ Rhodin, Michael Ogle, Russell A. Mittermeier, Herilala Randriamahazo, Rick Hudson, and Richard E. Lewis, (Eds). Astrochelys yniphora. Chelonian Research Monographs 6: 47-49, 2013.
Angelo Mandimbihasina, Andrea Currylow. New data on the naturally-occurring maximum sizes attained by Plowshare Tortoises (Astrochelys yniphora) . Herpetology Notes 7: 685-688, 2014.
John Morgan, Serene Chung. Rising internet-based trade in the Critically Endangered plowshare tortoise Astrochelys yniphora in Indonesia highlights need for improved enforcement of CITES . Oryx , 52 (4): 744-750, 2018. doi: 10.1017/S003060531700031X
Walker, R., Lewis, R., Mandimbihasina, A., Goode, E., Gibbons, P., Currylow, A., and Woolaver, L. The conservation of the world’s most threatened tortoise: the plowshare tortoise (Astrochelys yniphora) of Madagascar of Madagascar . Testudo (8) 2: 68-75, 2015.
