User:Ltomohara/Spiny turtle

Description

The spiny turtle is a medium-sized tortoise with a brown shell and red-spotted head. Also known as the “cog-wheel turtle,” it derives its name from its spiky-edged carapace, marginal scutes, and spiny keel. The origin of its common and specific name is immediately apparent from the sharp, pointed, spiky-edged carapace, and spiny keel, of this unique turtle, also known as the 'cog-wheel turtle'. As juvenile spiny turtles become adults, the black striped and yellow underside of their shell fades in color. In addition, the juveniles’ serrations, or jagged edges, at the carapace margin decrease in size and become restricted to the carapace’s rear margin. These changes of the spine and carapace serve as evolutionary adaptations attempting to prevent predators from preying on juvenile turtles.

Taxonomy

The spiny turtle belongs to the kingdom Animalia, the order of Testudines, and the genus of Heosemys. The classification of Heosemys incorporates four species: Heosemys annandalii, Heosemys depressa, Heosemys grandis, and Heosemys spinosa; however, relationships between the four are undetermined. Variation among the Heosemys spinosa is also uncertain, but it has been suggested that there are two types: a “mainland form” dwelling in Malaysia, Thailand, and southern Myanmar, and an “insular form” found in Indonesia and the Philippines, possibly in Brunei and Singapore as well.

Anatomy

Adult spiny turtles’ carapace length usually falls between 175 mm to 220 mm and their mass ranges from 1.5 kg to 2.0 kg.

Behavior

The spiny turtle buries itself in leaf litter to camouflage during the day and only emerges at night, foraging for food.

While often portrayed as a herbivore, the spiny turtle also eats carrion and insects alongside fruits and plants. Fruit from the yin-ngan tree is especially important for the turtle, and in Myanmar, the turtle often dwells beneath these trees when the trees are fruiting. Captive juvenile spiny turtles usually prefer to eat tomatoes. At the Kubah National Park in Sarawak, analysis of fecal content revealed the turtles’ role as seed dispersal agents, for their fecal matter contained five different seed types. Arthropods and hair were also found in the samples, suggesting consumption of mammals and other animals.

Reproduction

Regarding nesting behavior in the wild, the female lays one or two eggs in a nest and produces up to three clutches annually. Mating behaviour appears to be triggered by rain; in captivity, spraying males with water results in them chasing females and attempting to mount. To ease the delivery of the egg, a hinge forms in the female turtle’s plastron before it is laid. The egg is usually covered with a partial layer of substrate, and researchers have found eggs laid in a so-called “protected spot” underneath cork bark or thick foliage. Nothing is known of nesting behaviour in the wild. One, two, or rarely three eggs are laid per clutch; in captivity, laying usually occurs in the night or early morning. Females produce up to three clutches per year. A plastron hinge develops to ease laying. It has been bred in captivity several times; in three cases the incubation time was 106, 110, and 145 days.

Many attempts at reproduction in captivity have proved unsuccessful due to the eggs’ shells being thick and prone to bursting if the substrate is too damp. The first successful copulation in captivity occurred in 1991 at Zoo Atlanta, where incubation lasted for 106 days in a medium of peat moss, long fiber peat moss, and damp sand. For the first 35 days, the egg was incubated at a temperature of 28-30° C, and for the last 71 days, the temperature was decreased to 26-28°C.

Distribution

The spiny turtle is known from Brunei, Indonesia, Malaysia, Myanmar, the Philippines, Singapore, and Thailand.

Conservation

Labeled as “vulnerable” by the IUCN in 1996, the spiny turtle became endangered in 2000 when the supply of the species declined by a half in the Chinese food market. It is suggested that the main threat to the spiny turtle has been the destruction of natural forests to create oil palm plantations, common in southern Myanmar. The spiny turtle’s participation in the international pet trade and its use in traditional Chinese medicine has also led to its decline. However, numerous conservation efforts have been undertaken because the turtle is protected by the Philippines Wildlife Act and other initiatives. A spiny turtle hatching at the Chester Zoo in the UK in 2013 has also given hope to conservationists that the species may be retained.